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GIULIA CURIA

Professore Associato
Dipartimento di Scienze Biomediche, Metaboliche e Neuroscienze sede ex-Sc. Biomediche


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Pubblicazioni

2022 - Preface to 'Advanced neurotechnologies: Translating innovation for health and well-being' [Articolo su rivista]
Das, R.; Curia, G.; Heidari, H.
abstract


2021 - Correction to: The Future of Neuroscience: Flexible and Wireless Implantable Neural Electronics (Advanced Science, (2021), 8, 14, (2102287), 10.1002/advs.202102287) [Articolo su rivista]
Mcglynn, E.; Nabaei, V.; Ren, E.; Galeote-Checa, G.; Das, R.; Curia, G.; Heidari, H.
abstract

Adv. Sci. 2021, 8, 2002693 DOI: 10.1002/advs.202002693 In the originally published article, the funding information in the acknowledgment is not correct. Please find the correct acknowledgements here: Acknowledgements This work was supported by the European Union's Horizon 2020 Hybrid Enhanced Regenerative Medicine Systems (HERMES) project (GA n. 824164). The work of EM is also supported by the UK Engineering and Physical Sciences Research Council (EPSRC) DTP under grant number 2279645. The work of RD is also supported by the H2020 MSCA IF WiseCure (GA n. 893822).


2021 - Murine cerebral organoids develop network of functional neurons and hippocampal brain region identity [Articolo su rivista]
Ciarpella, F.; Zamfir, R. G.; Campanelli, A.; Ren, E.; Pedrotti, G.; Bottani, E.; Borioli, A.; Caron, D.; Di Chio, M.; Dolci, S.; Ahtiainen, A.; Malpeli, G.; Malerba, G.; Bardoni, R.; Fumagalli, G.; Hyttinen, J.; Bifari, F.; Palazzolo, G.; Panuccio, G.; Curia, G.; Decimo, I.
abstract

Brain organoids are in vitro three-dimensional (3D) self-organized neural structures, which can enable disease modeling and drug screening. However, their use for standardized large-scale drug screening studies is limited by their high batch-to-batch variability, long differentiation time (10–20 weeks), and high production costs. This is particularly relevant when brain organoids are obtained from human induced pluripotent stem cells (iPSCs). Here, we developed, for the first time, a highly standardized, reproducible, and fast (5 weeks) murine brain organoid model starting from embryonic neural stem cells. We obtained brain organoids, which progressively differentiated and self-organized into 3D networks of functional neurons with dorsal forebrain phenotype. Furthermore, by adding the morphogen WNT3a, we generated brain organoids with specific hippocampal region identity. Overall, our results showed the establishment of a fast, robust and reproducible murine 3D in vitro brain model that may represent a useful tool for high-throughput drug screening and disease modeling.


2021 - Synaptic reshaping and neuronal outcomes in the temporal lobe epilepsy [Articolo su rivista]
Ren, E.; Curia, G.
abstract

Temporal lobe epilepsy (TLE) is one of the most common types of focal epilepsy, character-ized by recurrent spontaneous seizures originating in the temporal lobe(s), with mesial TLE (mTLE) as the worst form of TLE, often associated with hippocampal sclerosis. Abnormal epileptiform discharges are the result, among others, of altered cell-to-cell communication in both chemical and electrical transmissions. Current knowledge about the neurobiology of TLE in human patients emerges from pathological studies of biopsy specimens isolated from the epileptogenic zone or, in a few more recent investigations, from living subjects using positron emission tomography (PET). To overcome limitations related to the use of human tissue, animal models are of great help as they allow the selection of homogeneous samples still presenting a more various scenario of the epileptic syndrome, the presence of a comparable control group, and the availability of a greater amount of tissue for in vitro/ex vivo investigations. This review provides an overview of the structural and functional alterations of synaptic connections in the brain of TLE/mTLE patients and animal models.


2021 - The Future of Neuroscience: Flexible and Wireless Implantable Neural Electronics [Articolo su rivista]
McGlynn, E.; Nabaei, V.; Ren, E.; Galeote-Checa, G.; Das, R.; Curia, G.; Heidari, H.
abstract

Neurological diseases are a prevalent cause of global mortality and are of growing concern when considering an ageing global population. Traditional treatments are accompanied by serious side effects including repeated treatment sessions, invasive surgeries, or infections. For example, in the case of deep brain stimulation, large, stiff, and battery powered neural probes recruit thousands of neurons with each pulse, and can invoke a vigorous immune response. This paper presents challenges in engineering and neuroscience in developing miniaturized and biointegrated alternatives, in the form of microelectrode probes. Progress in design and topology of neural implants has shifted the goal post toward highly specific recording and stimulation, targeting small groups of neurons and reducing the foreign body response with biomimetic design principles. Implantable device design recommendations, fabrication techniques, and clinical evaluation of the impact flexible, integrated probes will have on the treatment of neurological disorders are provided in this report. The choice of biocompatible material dictates fabrication techniques as novel methods reduce the complexity of manufacture. Wireless power, the final hurdle to truly implantable neural interfaces, is discussed. These aspects are the driving force behind continued research: significant breakthroughs in any one of these areas will revolutionize the treatment of neurological disorders.


2020 - Development of mouse hippocampal organoids [Abstract in Atti di Convegno]
Ciarpella, F; Zamfir, R; Campanelli, A; Dolci, S; Dichio, M; Patuzzo, C; Ren, E; Bardoni, R; Pedrotti, G; Mannino, L; Fumagalli, G; Ahtiainen, A; Malerba, G; Hyttinen, J; Panuccio, G; Palazzolo, G; Curia, G; Decimo, I
abstract


2020 - Implantable and Wearable Neuroengineering Education: A Review of Postgraduate Programmes [Articolo su rivista]
Ghannam, R.; Curia, G.; Brante, G.; Khosravi, S.; Fan, H.
abstract

Neurological diseases (NDs) such as epilepsy, dementia, Alzheimer's and Parkinson's disease currently affect almost two thirds of Europe's population. Furthermore, enormous financial commitments are required to deal with these diseases. Therefore, there is growing concern that countries with transitional economies may struggle to handle this financial burden, which warrants the urgent development of new technologies for early disease identification and treatment. Consequently, the aim of our article is to survey the range of postgraduate programmes that strive to nurture neuroengineering graduates who will excel in designing and developing implantable and wearable technologies for ND applications. Based on the basic building blocks of these technologies, we have identified four key areas that programmes need to cover, which include Neuroscience, Integrated Circuits, Communications and Signal Processing as well as Electronic Devices. According to our systematic review, a total of fifteen institutes satisfied our search criteria and provided the necessary neuroengineering training. The majority of these programmes are located in Europe and North America, which means that cross border and interdisciplinary efforts are required to develop educational programmes in countries most vulnerable to these diseases. We also provide recommendations for how these programmes can be delivered using non-traditional teaching approaches to ensure that graduates develop the necessary soft skills required by the constantly shifting job market.


2020 - In vitro biocompatibility screening of biopolymers for the development of neuromorphic medical devices [Abstract in Atti di Convegno]
Ren, E; Mcglynn, E; Das, R; Heidari, H; Puja, G; Curia, G
abstract


2020 - Local lesion in ventral CA3 induced by ibotenic acid [Abstract in Atti di Convegno]
Bartoletti, S; Santana Dos Santos, F; Dolci, S; Mannino, L; Decimo, I; Curia, G
abstract


2020 - Minimally invasive surgical strategies to implant cannula in CA3 ventral area [Abstract in Atti di Convegno]
Santana Dos Santos, F; Bartoletti, S; Dolci, S; Fontana, E; Decimo, I; Curia, G
abstract


2020 - Wearable Electronics for Neurological Applications: A Review of Undergraduate Engineering Programmes [Relazione in Atti di Convegno]
Ghannam, R.; Curia, G.; Brante, G.; Fan, H.; Heidari, H.
abstract

Neuroscientists accept that we are indeed faced with an overwhelming challenge in understanding how the brain works. A better understanding of the brain will ultimately enable us to appreciate how well our students have grasped their learning materials. It will also enable us to diagnose and treat neurological disorders more effectively. Designing and developing the next generation of wearable devices is an important steppingstone towards this endeavor. Consequently, interdisciplinary efforts are required in co-creating educational materials that enable future neuro-engineers to develop these new devices. The aim of this article is to present a review of current undergraduate programmes that deal with this issue. Moreover, we provide recommendations for how new programmes in this field can be organized and delivered to ensure effective benefit for transnational students.


2020 - microRNA Deficiency in VIP+ Interneurons Leads to Cortical Circuit Dysfunction [Articolo su rivista]
Qiu, Fang; Mao, Xingfeng; Liu, Penglai; Wu, Jinyun; Zhang, Yuan; Sun, Daijing; Zhu, Yueyan; Gong, Ling; Shao, Mengmeng; Fan, Keyang; Chen, Junjie; Lu, Jiangteng; Jiang, Yan; Zhang, Yubin; Curia, Giulia; Li, Anan; He, Miao
abstract

Genetically distinct GABAergic interneuron subtypes play diverse roles in cortical circuits. Previous studies revealed thatmicroRNAs (miRNAs) are differentially expressed in cortical interneuron subtypes, and are essential for the normalmigration, maturation, and survival of medial ganglionic eminence-derived interneuron subtypes. How miRNAs function invasoactive intestinal peptide expressing (VIP+) interneurons derived from the caudal ganglionic eminence remains elusive.Here, we conditionally removedDicerin postmitotic VIP+interneurons to block miRNA biogenesis. We found that theintrinsic and synaptic properties of VIP+interneurons and pyramidal neurons were concordantly affected prior to aprogressive loss of VIP+interneurons. In vivo recording further revealed elevated cortical local field potential power. Mutantmice had a shorter life span but exhibited better spatial working memory and motor coordination. Our results demonstratethat miRNAs are indispensable for the function and survival of VIP+interneurons, and highlight a key role of VIP+interneurons in cortical circuits.


2019 - Generation of 3D brain organoids to recapitulate hippocampal structure [Abstract in Atti di Convegno]
Ciarpella, F; Zamfir, R; Campanelli, A; Dichio, M; Pedrotti, G; Dolci, S; Mannino, L; Fumagalli, G; Curia, G; Panuccio, G; Palazzolo, G; Decimo, I
abstract


2019 - Use of high fidelity simulation: a two-year training project experience for third year students in Nursing Course Degree of Reggio Emilia [Relazione in Atti di Convegno]
Mecugni, Daniela; Curia, Giulia; Pisciotta, Alessandra; Amaducci, Giovanna
abstract

Nursing students at the end of their studies are supposed to own skills that allow them, in a short time, to act effectively and safely. Therefore, it is of primary importance that during the training period they have the opportunity, under protected conditions, to practice the management of scenarios realistically representative of the clinical setting. High-fidelity simulation workshops, aimed to provide adequate skills in the management of vital criticality, represent innovative and exciting learning tools, thanks to teaching method and forefront technology involved. The laboratory activities included allow the students to completely descend in simulated scenarios either by the use of computerized interactive cases and by computerized manikins. In our study both these types of simulation laboratories were proposed to 3rd year Nursing students attending the academic years 2015/2016 and 2016/2017. The survey administered to both groups at the end of the workshop revealed a highly positive feedback towards this innovative teaching approach that allowed the students to understand the correlation between pseudorealistic simulations and theoretical notions learned during lectures. The experience built through this two-year study allowed us to lay the bases for further studies on this topic.


2017 - FosB/ΔFosB and p-ERK1/2 expression respectively identified the lateral amygdala and CA1 as critical regions involved in the progressive seizure aggravation observed in mice exposed to repeated 6-Hz corneal stimulation [Abstract in Atti di Convegno]
Costa, Am; Giordano, C; Lucchi, C; Curia, G; Piat, M; Leo, G; Vinet, J; Biagini, G
abstract

FosB/ΔFosB and p-ERK1/2 expression respectively identified the lateral amygdala and CA1 as critical regions involved in the progressive seizure aggravation observed in mice exposed to repeated 6-Hz corneal stimulation


2017 - Hippocampal and neocortical dynamics at physiological or febrile temperature are not modified in the pre-epileptic period in a mouse model of Dravet syndrome. [Abstract in Atti di Convegno]
Curia, G; Lavigne, J; Mantegazza, M
abstract

Hippocampal and neocortical dynamics at physiological or febrile temperature are not modified in the pre-epileptic period in a mouse model of Dravet syndrome.


2017 - Involvement of PPARγ in the anticonvulsant activity of EP-80317, a ghrelin receptor antagonist [Articolo su rivista]
Lucchi, Chiara; Costa, ANNA MARIA; Giordano, Carmela; Curia, Giulia; Piat, Marika; Leo, Giuseppina; Vinet, Jonathan; Brunel, Luc; Fehrentz, Jean Alain; Martinez, Jean; Torsello, Antonio; Biagini, Giuseppe
abstract

Ghrelin, des-acyl ghrelin and other related peptides possess anticonvulsant activities. Although ghrelin and cognate peptides were shown to physiologically regulate only the ghrelin receptor, some of them were pharmacologically proved to activate the peroxisome proliferator-activated receptor gamma (PPARγ) through stimulation of the scavenger receptor CD36 in macrophages. In our study, we challenged the hypothesis that PPARγ could be involved in the anticonvulsant effects of EP-80317, a ghrelin receptor antagonist. For this purpose, we used the PPARγ antagonist GW9662 to evaluate the modulation of EP-80317 anticonvulsant properties in two different models. Firstly, the anticonvulsant effects of EP-80317 were studied in rats treated with pilocarpine to induce status epilepticus (SE). Secondly, the anticonvulsant activity of EP-80317 was ascertained in the repeated 6-Hz corneal stimulation model in mice. Behavioral and video electrocorticographic (ECoG) analyses were performed in both models. We also characterized levels of immunoreactivity for PPARγ in the hippocampus of 6-Hz corneally stimulated mice. EP-80317 predictably antagonized seizures in both models. Pre-treatment with GW9662 counteracted almost all EP-80317 effects both in mice and rats. Only the effects of EP-80317 on power spectra of ECoGs recorded during repeated 6-Hz corneal stimulation were practically unaffected by GW9662 administration. Moreover, GW9662 alone produced a decrease in the latency of tonic-clonic seizures and accelerated the onset of SE in rats. Finally, in the hippocampus of mice treated with EP-80317 we found increased levels of PPARγ immunoreactivity. Overall, these results support the hypothesis that PPARγ is able to modulate seizures and mediates the anticonvulsant effects of EP-80317.


2016 - MicroRNA-101 Regulates Multiple Developmental Programs to Constrain Excitation in Adult Neural Networks [Articolo su rivista]
Lippi, Giordano; Fernandes, Catarina C; Ewell, Laura A; John, Danielle; Romoli, Benedetto; Curia, Giulia; Taylor, Seth R; Frady, E.  Paxon; Jensen, Anne B; Liu, Jerry C; Chaabane, Melanie M; Belal, Cherine; Nathanson, Jason l; Zoli, Michele; Leutgeb, Jill K; Biagini, Giuseppe; Yeo, Gene W; Berg, Darwin K
abstract

A critical feature of neural networks is that they balance excitation and inhibition to prevent pathological dysfunction. How this is achieved is largely unknown, although deficits in the balance contribute to many neurological disorders. We show here that a microRNA (miR-101) is a key orchestrator of this essential feature, shaping the developing network to constrain excitation in the adult. Transient early blockade of miR-101 induces long-lasting hyper-excitability and persistent memory deficits. Using target site blockers in vivo, we identify multiple developmental programs regulated in parallel by miR-101 to achieve balanced networks. Repression of one target, NKCC1, initiates the switch in γ-aminobutyric acid (GABA) signaling, limits early spontaneous activity, and constrains dendritic growth. Kif1a and Ank2 are targeted to prevent excessive synapse formation. Simultaneous de-repression of these three targets completely phenocopies major dysfunctions produced by miR-101 blockade. Our results provide new mechanistic insight into brain development and suggest novel candidates for therapeutic intervention.


2016 - Microglia are less pro-inflammatory than myeloid infiltrates in the hippocampus of mice exposed to status epilepticus [Articolo su rivista]
Vinet, Jonathan; Vainchtein, Ilia D.; Spano, Maria Carlotta; Giordano, Carmela; Bordini, Domenico; Curia, Giulia; Dominici, Massimo; Boddeke, Hendrikus W. G. M.; Eggen, Bart J. L.; Biagini, Giuseppe
abstract

Activated microglia, astrogliosis, expression of pro-inflammatory cytokines, blood brain barrier (BBB) leakage and peripheral immune cell infiltration are features of mesial temporal lobe epilepsy. Numerous studies correlated the expression of pro-inflammatory cytokines with the activated morphology of microglia, attributing them a pro-epileptogenic role. However, microglia and myeloid cells such as macrophages have always been difficult to distinguish due to an overlap in expressed cell surface molecules. Thus, the detrimental role in epilepsy that is attributed to microglia might be shared with myeloid infiltrates. Here, we used a FACS-based approach to discriminate between microglia and myeloid infiltrates isolated from the hippocampus 24 h and 96 h after status epilepticus (SE) in pilocarpine-treated CD1 mice. We observed that microglia do not express MHCII whereas myeloid infiltrates express high levels of MHCII and CD40 96 h after SE. This antigen-presenting cell phenotype correlated with the presence of CD4pos T cells. Moreover, microglia only expressed TNFα 24 h after SE while myeloid infiltrates expressed high levels of IL-1β and TNFα. Immunofluorescence showed that astrocytes but not microglia expressed IL-1β. Myeloid infiltrates also expressed matrix metalloproteinase (MMP)-9 and 12 while microglia only expressed MMP-12, suggesting the involvement of both cell types in the BBB leakage that follows SE. Finally, both cell types expressed the phagocytosis receptor Axl, pointing to phagocytosis of apoptotic cells as one of the main functions of microglia. Our data suggests that, during early epileptogenesis, microglia from the hippocampus remain rather immune supressed whereas myeloid infiltrates display a strong inflammatory profile.


2016 - Modeling post-traumatic epilepsy for therapy development [Capitolo/Saggio]
Curia, Giulia; Eastman, C. L; Miller, J. W.; D’Ambrosio, R.
abstract

Epilepsy is the most prevalent serious neurological disorder, afflicting almost 1% of the population worldwide. It is a heterogeneous disorder, comprising numerous syndromes with a wide range of etiologies, that is defined by the manifestation of chronic spontaneous recurrent seizures (CSRSs). An epileptic seizure, in turn, is defined by the International League Against Epilepsy (ILAE) as “transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain”. Post-traumatic epilepsy (PTE) arises after mechanical damage to the brain and is diagnosed when spontaneous seizures are observed at least a week after brain injury. PTE is the most prevalent acquired epilepsy in young adults and accounts for 5% of epilepsies overall. There are currently no cures for PTE and no means to prevent the disorder in those at risk. Available treatments of PTE are symptomatic, and at least 40% of patients have seizures that cannot be controlled with any of the available drugs. This dire situation requires rethinking the development and use of animal models for the development of therapies for PTE. In this chapter we will introduce the problem and discuss several topics crucial for modeling PTE for therapy development.


2015 - Repeated 6-Hz Corneal Stimulation Progressively Increases FosB/ΔFosB Levels in the Lateral Amygdala and Induces Seizure Generalization to the Hippocampus [Articolo su rivista]
Giordano, Carmela; Vinet, Jonathan; Curia, Giulia; Biagini, Giuseppe
abstract

Exposure to repetitive seizures is known to promote convulsions which depend on specific patterns of network activity. We aimed at evaluating the changes in seizure phenotype and neuronal network activation caused by a modified 6-Hz corneal stimulation model of psychomotor seizures. Mice received up to 4 sessions of 6-Hz corneal stimulation with fixed current amplitude of 32 mA and inter-stimulation interval of 72 h. Video-electroencephalography showed that evoked seizures were characterized by a motor component and a non-motor component. Seizures always appeared in frontal cortex, but only at the fourth stimulation they involved the hippocampus, suggesting the establishment of an epileptogenic process. Duration of seizure non-motor component progressively decreased after the second session, whereas convulsive seizures remained unchanged. In addition, a more severe seizure phenotype, consisting of tonic-clonic generalized convulsions, was predominant after the second session. Immunohistochemistry and double immunofluorescence experiments revealed a significant increase in neuronal activity occurring in the lateral amygdala after the fourth session, most likely due to activity of principal cells. These findings indicate a predominant role of amygdala in promoting progressively more severe convulsions as well as the late recruitment of the hippocampus in the seizure spread. We propose that the repeated 6-Hz corneal stimulation model may be used to investigate some mechanisms of epileptogenesis and to test putative antiepileptogenic drugs.


2015 - Repeated 6-Hz corneal stimulation progressively increases FosB/∆FosB levels in the lateral amygdala and induces seizure generalization to the hippocampus. [Abstract in Atti di Convegno]
Giordano, C; Vinet, Jonathan; Curia, Giulia; Biagini, Giuseppe
abstract

Exposure to repetitive seizures is known to promote convulsions which depends on specific patterns of network activity. We aimed at evaluating the changes in seizure phenotype and neuronal network activation caused by the modified 6-Hz corneal stimulation model of psychomotor seizures. Mice received up to 4 sessions of 6-Hz corneal stimulation with fixed current amplitude of 32 mA and an inter-stimulation interval of 72 h. Video-electroencephalography showed that evoked seizures were characterized by a motor component and a non-motor component. Seizures appeared always in frontal cortex, but only at the fourth stimulation they involved the hippocampus. Duration of non-motor seizures progressively decreased after the second session, whereas convulsive seizures remained unchanged. In addition, a more severe seizure phenotype, consisting of tonic-clonic generalized convulsions, was predominant after the second session. Immunohistochemistry and double immunofluorescence experiments revealed a significant increase in neuronal activity occurring in the lateral amygdala after the fourth session most likely due to activity of principal cells. These findings suggest a predominant role of amygdala in promoting progressively more severe convulsions.


2015 - The role of seizures in the early stages of Alzheimer’s disease. [Abstract in Atti di Convegno]
Marchetti, C; Rizzello, E; Pimpinella, D; Curia, Giulia; Middei, S.
abstract

Epilepsy in Alzheimer Disease animal model and prevention of seizure by AED administration reduces cognitive deficits (compared to alzheimer animals with seizures untreated with AED)


2014 - Electrocorticography demonstrates beneficial effects of EP-80317 in a model of status epilepticus [Abstract in Atti di Convegno]
Lucchi, C; Curia, Giulia; Torsello, A; Biagini, Giuseppe
abstract

Status epilepticus (SE) is a serious life-threatening condition. Treatment of SE is based on a stage approach, going from benzodiazepines in the early stage to intensive care unit and general anesthesia in severe stages. Treatment of SE is frequently unsuccessful, and high levels of mortality and morbidity are reported. Several risk factors for SE occurrence and recurrence have been identified, making prevention of this condition a primary objective. EP-80317, a ghrelin receptor antagonist, displays anticonvulsant properties on behavioral convulsive episodes. In this study, we have characterized the ability of EP-80317 to prevent progression from non-convulsive to convulsive seizures and to SE in the pilocarpine model by video-electrocorticography. SE developed in 100% of rats pretreated with saline, but only in 50% of those pretreated with EP-80317. Seizures were similarly evoked in both groups, but different rates of convulsive vs. non-convulsive episodes were observed. In particular, the rate of convulsive seizures was 15% in EP-80317-pretreated rats that did not experience SE (EP-80317/Non-SE), whereas it was about 75% in saline-pretreated group and in EP-80317-pretreated rats that experienced SE (EP-80317/SE). Moreover, after pilocarpine administration, saline-pretreated and EP-80317/SE rats showed a worsening in behavioral manifestation and seizure duration, and a progression of the power spectrum of convulsive seizures. This progressive worsening was not observed in EP-80317/Non-SE rats. We report for the first time that EP-80317 prevents the progression from non-convulsive to convulsive seizures and to SE in pilocarpine-treated rats.


2014 - Electrographic and behavioral characterization of EP-80317 anticonvulsant effects in pilocarpine-treated rats. [Abstract in Rivista]
Curia, Giulia; Lucchi, Chiara; Torsello, A; Biagini, Giuseppe
abstract

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2014 - Pathophysiogenesis of Mesial Temporal Lobe Epilepsy: Is Prevention of Damage Antiepileptogenic? [Articolo su rivista]
Curia, Giulia; Lucchi, Chiara; Vinet, Jonathan; Gualtieri, F; Marinelli, C; Torsello, A; Costantino, Luca; Biagini, Giuseppe
abstract

Temporal lobe epilepsy (TLE) is frequently associated with hippocampal sclerosis, possibly caused by a primary brain injury that occurred a long time before the appearance of neurological symptoms. This type of epilepsy is characterized by refractoriness to drug treatment, so to require surgical resection of mesial temporal regions involved in seizure onset. Even this last therapeutic approach may fail in giving relief to patients. Although prevention of hippocampal damage and epileptogenesis after a primary event could be a key innovative approach to TLE, the lack of clear data on the pathophysiological mechanisms leading to TLE does not allow any rational therapy. Here we address the current knowledge on mechanisms supposed to be involved in epileptogenesis, as well as on the possible innovative treatments that may lead to a preventive approach. Besides loss of principal neurons and of specific interneurons, network rearrangement caused by axonal sprouting and neurogenesis are well known phenomena that are integrated by changes in receptor and channel functioning and modifications in other cellular components. In particular, a growing body of evidence from the study of animal models suggests that disruption of vascular and astrocytic components of the blood-brain barrier takes place in injured brain regions such as the hippocampus and piriform cortex. These events may be counteracted by drugs able to prevent damage to the vascular component, as in the case of the growth hormone secretagogue ghrelin and its analogues. A thoroughly investigation on these new pharmacological tools may lead to design effective preventive therapies.


2014 - Proprietà anticonvulsivanti di ligandi del recettore GHS-R1a. [Abstract in Atti di Convegno]
Biagini, Giuseppe; Giordano, Carmela; Lucchi, Chiara; Marchio', Maddalena; Bresciani, E; Torsello, A; Curia, Giulia
abstract

Status epilepticus (SE) is a serious life-threatening condition. Treatment of SE is based on a stage approach, going from benzodiazepines in the early stage to intensive care unit and general anesthesia in severe stages. Treatment of SE is frequently unsuccessful, and high levels of mortality and morbidity are reported. Several risk factors for SE occurrence and recurrence have been identified, making prevention of this condition a primary objective. EP-80317, a ghrelin receptor antagonist, displays anticonvulsant properties on behavioral convulsive episodes. In this study, we have characterized the ability of EP-80317 to prevent progression from non-convulsive to convulsive seizures and to SE in the pilocarpine model by video-electrocorticography. SE developed in 100% of rats pretreated with saline, but only in 50% of those pretreated with EP-80317. Seizures were similarly evoked in both groups, but different rates of convulsive vs. non-convulsive episodes were observed. In particular, the rate of convulsive seizures was 15% in EP-80317-pretreated rats that did not experience SE (EP-80317/Non-SE), whereas it was about 75% in saline-pretreated group and in EP-80317-pretreated rats that experienced SE (EP-80317/SE). Moreover, after pilocarpine administration, saline-pretreated and EP-80317/SE rats showed a worsening in behavioral manifestation and seizure duration, and a progression of the power spectrum of convulsive seizures. This progressive worsening was not observed in EP-80317/Non-SE rats. We report for the first time that EP-80317 prevents the progression from non-convulsive to convulsive seizures and to SE in pilocarpine-treated rats.


2013 - Neurosteroids And Epileptogenesis [Articolo su rivista]
Biagini, Giuseppe; Rustichelli, Cecilia; Curia, Giulia; Vinet, Jonathan; Lucchi, Chiara; Pugnaghi, Matteo; Meletti, Stefano
abstract

Epileptogenesis is defined as the latent period at the end of which spontaneous recurrent seizures occur. This concept has been recently re-evaluated to include exacerbation of clinically-manifested epilepsy. Thus, in patients affected by pharmacoresistant seizures, the progression toward a worse condition may be viewed as the result of a durable epileptogenic process. However, the mechanism potentially responsible for this progression remains unclear. Neuroinflammation has been consistently detected both in the latent period and in the chronic phase of epilepsy, especially when brain damage is present. This phenomenon is accompanied by glial cell reaction, leading to gliosis. We have previously described rats presenting an increased expression of the cytochrome P450 cholesterol side-chain cleavage (P450scc) enzyme, during the latent period, in glial cells of the hippocampus. The P450scc enzyme is critically involved in the synthesis of neurosteroids and its upregulation is associated with a delayed appearance of spontaneous recurrent seizures in rats that experienced status epilepticus (SE) induced by pilocarpine. Moreover, by decreasing the synthesis of neurosteroids able to promote inhibition, such as allopregnanolone, through administration of the 5α-reductase blocker finasteride, it is possible to terminate the latent period in pilocarpine-treated rats. Finasteride was also found to promote seizures in the chronic period of epileptic rats, suggesting that neurosteroids are continuously produced to counteract seizures. In humans, exacerbation of epilepsy has been also described in patients occasionally exposed to finasteride. Overall, these findings suggest a major role of neurosteroids in the progression of epilepsy and a possible antiepileptogenic role of allopregnanolone and cognate molecules.


2013 - Neurosteroids and epileptogenesis. [Abstract in Atti di Convegno]
Biagini, Giuseppe; Rustichelli, Cecilia; Curia, Giulia; Lucchi, Chiara; Pugnaghi, Matteo; Meletti, Stefano; Avoli, M.
abstract

Epileptogenesis is defined as the latent period at the end of which spontaneous recurrent seizures occur. This concept has been recently re-evaluated to include exacerbation of clinically-manifested epilepsy. Thus, in patients affected by pharmacoresistant seizures, the progression toward a worse condition may be viewed as the result of a durable epileptogenic process. However, the mechanism potentially responsible for this progression remains unclear. Neuroinflammation has been consistently detected both in the latent period and in the chronic phase of epilepsy, especially when brain damage is present. This phenomenon is accompanied by glial cell reaction, leading to gliosis. We have previously described rats presenting an increased expression of the cytochrome P450 cholesterol side-chain cleavage (P450scc) enzyme, during the latent period, in glial cells of the hippocampus. The P450scc enzyme is critically involved in the synthesis of neurosteroids and its up-regulation is associated with a delayed appearance of spontaneous recurrent seizures in rats that experienced status epilepticus induced by pilocarpine. Moreover, by decreasing the synthesis of neurosteroids able to promote inhibition, such as allopregnanolone, through the administration of the 5α-reductase blocker finasteride, it is possible to terminate the latent period in pilocarpine-treated rats. Finasteride was also found to promote seizures in the chronic period of epileptic rats, suggesting that neurosteroids are continuously produced to counteract seizures. In humans, exacerbation of epilepsy has been also described in patients occasionally exposed to finasteride. Overall, these findings suggest a major role of neurosteroids in the progression of epilepsy and a possible antiepileptogenic role of allopregnanolone and cognate molecules.


2013 - Protective but Not Anticonvulsant Effects of Ghrelin and JMV-1843 in the Pilocarpine Model of Status epilepticus. [Articolo su rivista]
Lucchi, Chiara; Curia, Giulia; Vinet, Jonathan; Gualtieri, Fabio; Bresciani, E; Locatelli, V; Torsello, A; Biagini, Giuseppe
abstract

In models of status epilepticus ghrelin displays neuroprotective effects mediated by the growth hormone secretagogue-receptor 1a (GHS-R1a). This activity may be explained by anticonvulsant properties that, however, are controversial. We further investigated neuroprotection and the effects on seizures by comparing ghrelin with a more effective GHS-R1a agonist, JMV-1843. Rats were treated either with ghrelin, JMV-1843 or saline 10 min before pilocarpine, which was used to induce status epilepticus. Status epilepticus, developed in all rats, was attenuated by diazepam. No differences were observed among the various groups in the characteristics of pilocarpine-induced seizures. In saline group the area of lesion, characterized by lack of glial fibrillary acidic protein immunoreactivity, was of 0.45±0.07 mm2 in the hippocampal stratum lacunosum-moleculare, and was accompanied by upregulation of laminin immunostaining, and by increased endothelin-1 expression. Both ghrelin (P<0.05) and JMV-1843 (P<0.01) were able to reduce the area of loss in glial fibrillary acidic protein immunostaining. In addition, JMV-1843 counteracted (P<0.05) the changes in laminin and endothelin-1 expression, both increased in ghrelin-treated rats. JMV-1843 was able to ameliorate neuronal survival in the hilus of dentate gyrus and medial entorhinal cortex layer III (P<0.05 vs saline and ghrelin groups). These results demonstrate diverse protective effects of growth hormone secretagogues in rats exposed to status epilepticus.


2013 - Protective but not anticonvulsive effects of ghrelin and JMV-1843 in the pilocarpine model of status epilepticus. [Abstract in Atti di Convegno]
Lucchi, Chiara; Curia, Giulia; Vinet, Jonathan; Gualtieri, F; Torsello, A; Biagini, Giuseppe
abstract

In models of status epilepticus ghrelin displays neuroprotective effects mediated by the growth hormone secretagogue-receptor 1a (GHS-R1a). This activity may be explained by anticonvulsant properties that, however, are controversial. We further investigated neuroprotection and the effects on seizures by comparing ghrelin with a more effective GHS-R1a agonist, JMV-1843. Rats were treated either with ghrelin, JMV-1843 or saline 10 min before pilocarpine, which was used to induce status epilepticus. Status epilepticus, developed in all rats, was attenuated by diazepam. No differences were observed among the various groups in the characteristics of pilocarpine-induced seizures. In saline group the area of lesion, characterized by lack of glial fibrillary acidic protein immunoreactivity, was of 0.45 ± 0.07 mm(2) in the hippocampal stratum lacunosum-moleculare, and was accompanied by upregulation of laminin immunostaining, and by increased endothelin-1 expression. Both ghrelin (P<0.05) and JMV-1843 (P<0.01) were able to reduce the area of loss in glial fibrillary acidic protein immunostaining. In addition, JMV-1843 counteracted (P<0.05) the changes in laminin and endothelin-1 expression, both increased in ghrelin-treated rats. JMV-1843 was able to ameliorate neuronal survival in the hilus of dentate gyrus and medial entorhinal cortex layer III (P<0.05 vs saline and ghrelin groups). These results demonstrate diverse protective effects of growth hormone secretagogues in rats exposed to status epilepticus.


2013 - Resilience to audiogenic seizures is associated with p-ERK1/2 dephosphorylation in the subiculum of Fmr1 knockout mice [Articolo su rivista]
Curia, Giulia; Gualtieri, Fabio; Bartolomeo, Regina; Riccardo, Vezzali; Biagini, Giuseppe
abstract

Young, but not adult, Fmr1 knockout (KO) mice display audiogenic seizures (AGS) that can be prevented by inhibiting extracellular signal-regulated kinases 1/2 (ERK1/2) phosphorylation. In order to identify the cerebral regions involved in these phenomena, we characterized the response to AGS in Fmr1 KO mice and wild type (WT) controls at postnatal day (P) 45 and P90. To characterize the diverse response to AGS in various cerebral regions, we evaluated the activity markers FosB/ΔFosB and phosphorylated ERK1/2 (p-ERK1/2). Wild running (100% of tested mice) followed by clonic/tonic seizures (30%) were observed in P45 Fmr1 KO mice, but not in WT mice. In P90 Fmr1 KO mice, wild running was only present in 25% of tested animals. Basal FosB/ΔFosB immunoreactivity was higher (P<0.01 vs WT) in the CA1 and subiculum of P45 Fmr1 KO mice. Following the AGS test, FosB/ΔFosB expression consistently increased in most of the analyzed regions in both groups at P45, but not at P90. Interestingly, FosB/ΔFosB immunoreactivity was significantly higher in P45 Fmr1 KO mice in the medial geniculate body (P<0.05 vs WT) and CA3 (P<0.01). Neurons presenting with immunopositivity to p-ERK1/2 were more abundant in the subiculum of Fmr1 KO mice in control condition (P<0.05 vs WT, in both age groups). In this region, p-ERK1/2-immunopositive cells significantly decreased (-75%, P<0.01) in P90 Fmr1 KO mice exposed to the AGS test, but no changes were found in P45 mice or in other brain regions. In both age groups of WT mice, p-ERK1/2-immunopositive cells increased in the subiculum after exposure to the acoustic test. Our findings illustrate that FosB/ΔFosB markers are overexpressed in the medial geniculate body and CA3 in Fmr1 KO mice experiencing AGS, and that p-ERK1/2 is markedly decreased in the subiculum of Fmr1 KO mice resistant to AGS induction. These findings suggest that resilience to AGS is associated with dephosphorylation of p-ERK1/2 in the subiculum of mature Fmr1 KO mice.


2013 - Resilience to audiogenic seizures is associated with p-ERK1/2 dephosphorylation in the subiculum of a mice model of Fragile X syndrome. [Abstract in Atti di Convegno]
Curia, Giulia; Gualtieri, F; Bartolomeo, Regina; Vezzali, R; Biagini, Giuseppe
abstract

Young, but not adult, fragile X mental retardation gene (Fmr1) knockout (KO) mice display audiogenic seizures (AGS) that can be prevented by inhibiting extracellular signal-regulated kinases 1/2 (ERK1/2) phosphorylation. In order to identify the cerebral regions involved in these phenomena, we characterized the response to AGS in Fmr1 KO mice and wild type (WT) controls at postnatal day (P) 45 and P90. To characterize the diverse response to AGS in various cerebral regions, we evaluated the activity markers FosB/ΔFosB and phosphorylated ERK1/2 (p-ERK1/2). Wild running (100% of tested mice) followed by clonic/tonic seizures (30%) were observed in P45 Fmr1 KO mice, but not in WT mice. In P90 Fmr1 KO mice, wild running was only present in 25% of tested animals. Basal FosB/ΔFosB immunoreactivity was higher (P < 0.01 vs. WT) in the CA1 and subiculum of P45 Fmr1 KO mice. Following the AGS test, FosB/ΔFosB expression consistently increased in most of the analyzed regions in both groups at P45, but not at P90. Interestingly, FosB/ΔFosB immunoreactivity was significantly higher in P45 Fmr1 KO mice in the medial geniculate body (P < 0.05 vs. WT) and CA3 (P < 0.01). Neurons presenting with immunopositivity to p-ERK1/2 were more abundant in the subiculum of Fmr1 KO mice in control condition (P < 0.05 vs. WT, in both age groups). In this region, p-ERK1/2-immunopositive cells significantly decreased (-75%, P < 0.01) in P90 Fmr1 KO mice exposed to the AGS test, but no changes were found in P45 mice or in other brain regions. In both age groups of WT mice, p-ERK1/2-immunopositive cells increased in the subiculum after exposure to the acoustic test. Our findings illustrate that FosB/ΔFosB markers are overexpressed in the medial geniculate body and CA3 in Fmr1 KO mice experiencing AGS, and that p-ERK1/2 is markedly decreased in the subiculum of Fmr1 KO mice resistant to AGS induction. These findings suggest that resilience to AGS is associated with dephosphorylation of p-ERK1/2 in the subiculum of mature Fmr1 KO mice


2012 - Increased perivascular laminin predicts damage to astrocytes in CA3 and piriform cortex following chemoconvulsive treatments. [Articolo su rivista]
Gualtieri, Fabio; Curia, Giulia; C., Marinelli; Biagini, Giuseppe
abstract

Status epilepticus (SE) induced by pilocarpine or kainate is associated with yet notsystemically investigated astrocytic and vascular injuries. To investigate their possibleassociation with neuronal damage, the changes in glial fibrillary acidic protein (GFAP),laminin and neuron-specific nuclear protein (NeuN) immunoreactivities were analyzed in ratstreated with pilocarpine (380 mg/kg) or kainate (15 mg/kg), and receiving diazepam (20mg/kg) after 10 min of SE. A different group of rats was injected with endothelin-1 (ET-1) inthe caudate putamen to reproduce the changes in GFAP and laminin immunoreactivitiesassociated with ischemia. Focal loss of GFAP immunostaining was accompanied byincreased laminin immunoreactivity in blood vessels, in all the examined groups. Regressionanalysis revealed a significant (P < 0.01) relationship between astrocytic lesion andincreased laminin immunoreactivity in the piriform cortex (Pir) of both pilocarpine (R2 = 0.88)and kainate (R2 = 0.94) groups of treatment. A significant relationship (P < 0.01; R2 = 0.81)was also present in the CA3 hippocampal region of pilocarpine-treated rats. At variance,neuronal and glial lesions were significantly related (P < 0.05, R2 = 0.74) only in thesubstantia nigra of pilocarpine-treated rats. The ratio between areas of GFAP and lamininchanges of immunoreactivity in the ET-1 group was similar to those found in pilocarpineandkainate-treated rats in specific brain regions, such as the hippocampal CA3 subfield, Pirand the anterior olfactory nucleus. The amygdala and submedius thalamic nucleus in thepilocarpine group, and the perirhinal and entorhinal cortices in the kainate group, alsopresented ischemic-like changes. These results indicate that laminin immunoreactivity isupregulated in the basal lamina of blood vessels after SE induced by pilocarpine or kainate.This phenomenon is significantly associated with lesions involving more glial than neuronalcells, in specific cerebral regions.


2011 - A blind randomized study of anti-epileptic and anti-epileptogenic effects of carisbamate on posttraumatic epilepsy in the rat. [Abstract in Rivista]
Eastman, C; Fender, J; Verley, D; Stewart, T; Curia, Giulia; Nov, E; D’Ambrosio, R.
abstract

carisbamate


2011 - Antiepileptic and Antiepileptogenic performance of Carisbamate after head injury in the rat: blind and randomized studies. [Articolo su rivista]
Eastman, Cl; Verley, Dr; Fender, Js; Stewart, Th; Nov, E; Curia, Giulia; D’Ambrosio, R.
abstract

Carisbamate (CRS) exhibits broad acute anticonvulsant activity in conventional anticonvulsant screens, genetic models of absence epilepsy and audiogenic seizures, and chronic spontaneous motor seizures arising after chemoconvulsant-induced status epilepticus. In add-on phase III trials with pharmacoresistant patients CRS induced < 30% average decreases in partial-onset seizure frequency. We assessed the antiepileptogenic and antiepileptic performance of subchronic CRS administration on posttraumatic epilepsy (PTE) induced by rostral parasaggital fluid percussion injury (rpFPI), which closely replicates human contusive closed head injury. Studies were blind and randomized, and treatment effects were assessed on the basis of sensitive electrocorticography (ECoG) recordings. Antiepileptogenic effects were assessed in independent groups of control and CRS-treated rats, at 1 and 3 months postinjury, after completion of a 2-week prophylactic treatment initiated 15 min after injury. The antiepileptic effects of 1-week CRS treatments were assessed in repeated measures experiments at 1 and 4 months postinjury. The studies were powered to detect ~50 and ~40% decreases in epilepsy incidence and frequency of seizures, respectively. Drug/vehicle treatment, ECoG analysis, and [CRS](plasma) determination all were performed blind. We detected no antiepileptogenic and an equivocal transient antiepileptic effects of CRS despite [CRS](plasma) comparable with or higher than levels attained in previous preclinical and clinical studies. These findings contrast with previous preclinical data demonstrating large efficacy of CRS, but agree with the average effect of CRS seen in clinical trials. The data support the use of rpFPI-induced PTE in the adolescent rat as a model of pharmacoresistant epilepsy for preclinical development.


2011 - Audiogenic seizures selectively activate hippocampal neurons in young mice affected by fragile X syndrome [Abstract in Atti di Convegno]
Gualtieri, F; Bartolomeo, Regina; Vezzali, R; Curia, Giulia; Biagini, Giuseppe
abstract

Young, but not adult, fragile X mental retardation gene (Fmr1) knockout (KO) mice display audiogenic seizures (AGS) that can be prevented by inhibiting extracellular signal-regulated kinases 1/2 (ERK1/2) phosphorylation. In order to identify the cerebral regions involved in these phenomena, we characterized the response to AGS in Fmr1 KO mice and wild type (WT) controls at postnatal day (P) 45 and P90. To characterize the diverse response to AGS in various cerebral regions, we evaluated the activity markers FosB/ΔFosB and phosphorylated ERK1/2 (p-ERK1/2). Wild running (100% of tested mice) followed by clonic/tonic seizures (30%) were observed in P45 Fmr1 KO mice, but not in WT mice. In P90 Fmr1 KO mice, wild running was only present in 25% of tested animals. Basal FosB/ΔFosB immunoreactivity was higher (P < 0.01 vs. WT) in the CA1 and subiculum of P45 Fmr1 KO mice. Following the AGS test, FosB/ΔFosB expression consistently increased in most of the analyzed regions in both groups at P45, but not at P90. Interestingly, FosB/ΔFosB immunoreactivity was significantly higher in P45 Fmr1 KO mice in the medial geniculate body (P < 0.05 vs. WT) and CA3 (P < 0.01). Neurons presenting with immunopositivity to p-ERK1/2 were more abundant in the subiculum of Fmr1 KO mice in control condition (P < 0.05 vs. WT, in both age groups). In this region, p-ERK1/2-immunopositive cells significantly decreased (-75%, P < 0.01) in P90 Fmr1 KO mice exposed to the AGS test, but no changes were found in P45 mice or in other brain regions. In both age groups of WT mice, p-ERK1/2-immunopositive cells increased in the subiculum after exposure to the acoustic test. Our findings illustrate that FosB/ΔFosB markers are overexpressed in the medial geniculate body and CA3 in Fmr1 KO mice experiencing AGS, and that p-ERK1/2 is markedly decreased in the subiculum of Fmr1 KO mice resistant to AGS induction. These findings suggest that resilience to AGS is associated with dephosphorylation of p-ERK1/2 in the subiculum of mature Fmr1 KO mice.


2011 - Impact of injury location and severity on posttraumatic epilepsy in the rat: role of frontal neocortex [Articolo su rivista]
Curia, Giulia; Levitt, Michael; Fender, Jason S; Miller, John W; Ojemann, Jeffrey; D'Ambrosio, Raimondo
abstract

Human posttraumatic epilepsy (PTE) is highly heterogeneous, ranging from mild remitting to progressive disabling forms. PTE results in simple partial, complex partial, and secondarily generalized seizures with a wide spectrum of durations and semiologies. PTE variability is thought to depend on the heterogeneity of head injury and patient's age, gender, and genetic background. To better understand the role of these factors, we investigated the seizures resulting from calibrated fluid percussion injury (FPI) to adolescent male Sprague-Dawley rats with video electrocorticography. We show that PTE incidence and the frequency and severity of chronic seizures depend on the location and severity of FPI. The frontal neocortex was more prone to epileptogenesis than the parietal and occipital, generating earlier, longer, and more frequent partial seizures. A prominent limbic focus developed in most animals, regardless of parameters of injury. Remarkably, even with carefully controlled injury parameters, including type, severity, and location, the duration of posttraumatic apnea and the age and gender of outbred rats, there was great subject-to-subject variability in frequency, duration, and rate of progression of seizures, indicating that other factors, likely the subjects' genetic background and physiological states, have critical roles in determining the characteristics of PTE.


2010 - Effect of carbamazepine and oxcarbazepine on wild-type and mutant neuronal nicotinic acetylcholine receptors linked to nocturnal frontal lobe epilepsy [Articolo su rivista]
Di Resta, Chiara; Ambrosi, Paola; Curia, Giulia; Becchetti, Andrea
abstract

Carbamazepine (5H-dibenz[b,f]azepine-5-carboxamide) and oxcarbazepine (10,11-dihydro-10-oxo-5H-dibenz[b,f]azepine-5-carboxamide) are widely used for the treatment of partial epilepsy. Recent work indicates that these drugs, in addition to targeting voltage-gated Na(+) channels, can modulate ligand-gated channels. These compounds appear to be particularly effective for treatment of nocturnal frontal lobe epilepsy, which can be caused by mutant neuronal nicotinic receptors. We compared the effects of carbamazepine and oxcarbazepine on heteromeric nicotinic receptors to better understand the underlying mechanism of the effect of these drugs in epileptic patients. Receptors were expressed in cell lines and studied by patch-clamp methods at -60 mV. For alpha2beta4 receptors activated with 100 microM nicotine, IC(50) for carbamazepine was 49 microM. Receptors in which alpha2 was substituted with alpha2-I279 N, linked to autosomal dominant nocturnal frontal lobe epilepsy, had an IC(50) of 21 microM. For oxcarbazepine, the IC(50) was larger than 500 microM for wild-type receptors and approximately 100 microM for mutant receptors. A similar inhibition was observed in the presence of 10 microM nicotine, indicating a non-competitive mechanism. The monohydroxy derivative (MHD) of oxcarbazepine, clinically the most relevant compound, was tested on both alpha2beta4 and alpha4beta2 receptors, to obtain a broader view of its possible physiological effects. At the typical concentration present in blood (100 microM), MHD produced an approximate 40% channel block on alpha4beta2, but no significant effect on alpha2beta4 receptors. Oxcarbazepine and MHD retarded the channel deactivation, suggesting that these compounds produce open channel block. These results may explain the particular efficacy of these drugs in nocturnal frontal lobe epilepsy.


2010 - Voltage-gated sodium channels as therapeutic targets in epilepsy and other neurological disorders [Articolo su rivista]
Mantegazza, M.; Curia, Giulia; Biagini, Giuseppe; Ragsdale, D.; Avoli, M.
abstract

Voltage-gated sodium channels (VGSCs) are key mediators of intrinsic neuronal and muscle excitability. AbnormalVGSC activity is central to the pathophysiology of epileptic seizures, and many of the most widely used antiepilepticdrugs, including phenytoin, carbamazepine, and lamotrigine, are in hibitors of VGSC function. These antiepilepticdrugs might also be effi cacious in the treatment of other nervous system disorders, such as migraine, multiplesclerosis, neurodegenerative diseases, and neuropathic pain. In this Review, we summarise the structure and functionof VGSCs and their involvement in the pathophysiology of several neurological disorders. We also describe thebiophysical and molecular bases for the mechanisms of action of antiepileptic VGSC blockers and discuss the effi cacyof these drugs in the treat ment of epileptic and non-epileptic disorders. Overall, clinical and experimental data indicatethat these drugs are effi cacious for a range of diseases, and that the development of drugs with enhanced selectivity forspecifi c VGSC isoforms might be an eff ective and novel approach for the treatment of several neurological diseases.


2009 - Downregulation of tonic GABAergic inhibition in a mouse model of fragile X syndrome [Articolo su rivista]
Curia, Giulia; Papouin, Thomas; Séguéla, Philippe; Avoli, Massimo
abstract

The absence of fragile X mental retardation protein results in the fragile X syndrome (FXS), a common form of mental retardation associated with attention deficit, autistic behavior, and epileptic seizures. The phenotype of FXS is reproduced in fragile X mental retardation 1 (fmr1) knockout (KO) mice that have region-specific altered expression of some gamma-aminobutyric acid (GABA(A)) receptor subunits. However, little is known about the characteristics of GABAergic inhibition in the subiculum of these animals. We employed patch-clamp recordings from subicular pyramidal cells in an in vitro slice preparation. In addition, semiquantitative polymerase chain reaction and western blot experiments were performed on subiculum obtained from wild-type (WT) and KO mice. We found that tonic GABA(A) currents were downregulated in fmr1 KO compared with WT neurons, whereas no significant differences were observed in phasic GABA(A) currents. Molecular biology analysis revealed that the tonic GABA(A) receptor subunits alpha5 and delta were underexpressed in the fmr1 KO mouse subiculum compared with WT. Because the subiculum plays a role in both cognitive functions and epileptic disorders, we propose that altered tonic inhibition in this structure contributes to the behavioral deficits and epileptic activity seen in FXS patients. This conclusion is in line with evidence implicating tonic GABA(A) inhibition in learning and memory.


2009 - Epileptiform synchronization in the cingulate cortex [Articolo su rivista]
Panuccio, Gabriella; Curia, Giulia; Colosimo, Alfredo; Cruccu, Giorgio; Avoli, Massimo
abstract

The anterior cingulate cortex (ACC)--which plays a role in pain, emotions and behavior--can generate epileptic seizures. To date, little is known on the neuronal mechanisms leading to epileptiform synchronization in this structure. Therefore, we investigated the role of excitatory and inhibitory synaptic transmission in epileptiform activity in this cortical area. In addition, since the ACC presents with a high density of opioid receptors, we studied the effect of opioid agonism on epileptiform synchronization in this brain region.


2009 - Frontal neocortex is more epileptogenic than parietal and parietal-occipital neocortices after fluid percussion injury in the rat [Abstract in Rivista]
Curia, Giulia; Fender, Js; D’Ambrosio, R.
abstract

PTE


2009 - Lacosamide: a new approach to target voltage-gated sodium currents in epileptic disorders [Articolo su rivista]
Curia, Giulia; Biagini, Giuseppe; E., Perucca; M., Avoli
abstract

The mechanism of action of several antiepileptic drugs (AEDs) rests on their ability tomodulate the activity of voltage-gated sodium currents that are responsible for fast action potentialgeneration. Recent data indicate that lacosamide - a compound with analgesic and anticonvulsanteffects in animal models - shares a similar mechanism. When compared with other AEDs, lacosamidehas the unique ability to interact with sodium channel slow inactivation without affecting fastinactivation. This article reviews these findings and discusses their relevance within the context ofneuronal activity seen during epileptiform discharges generated by limbic neuronal networks in thepresence of chemical convulsants. These seizure-like events are characterized by sustained dischargesof sodium-dependent action potentials supported by robust depolarizations thus providingsynchronization within neuronal networks. Generally, AEDs such as phenytoin, carbamazepine andlamotrigine block sodium channels when activated. By contrasts, lacosamide facilitates slowinactivation of sodium channels both in term of kinetics and voltage-dependency. This effect may berelatively selective for repeatedly depolarized neurons such as those participating in seizure activity inwhich the persistence of sodium currents is more pronounced and promotes neuronal excitation. Theclinical effectiveness of lacosamide has been demonstrated in randomized placebo-controlled doubleblindparallel-group, adjunctive-therapy trials in patients with refractory partial seizures. Furtherstudies should determine whether lacosamide effects in animal models and in clinical settings are fullyexplained by its selective action on sodium current slow inactivation or whether other effects (e.g.,interactions with the collapsin-response mediator protein 2) play a contributory role.


2008 - Downregulation of tonic GABAA receptor-mediated inhibition in a mouse model of Fragile X syndrome [Abstract in Atti di Convegno]
Curia, Giulia; Papouin, T; Seguela, P; Avoli, M.
abstract

The absence of fragile X mental retardation protein results in the fragile X syndrome (FXS), a common form of mental retardation associated with attention deficit, autistic behavior, and epileptic seizures. The phenotype of FXS is reproduced in fragile X mental retardation 1 (fmr1) knockout (KO) mice that have region-specific altered expression of some gamma-aminobutyric acid (GABA(A)) receptor subunits. However, little is known about the characteristics of GABAergic inhibition in the subiculum of these animals. We employed patch-clamp recordings from subicular pyramidal cells in an in vitro slice preparation. In addition, semiquantitative polymerase chain reaction and western blot experiments were performed on subiculum obtained from wild-type (WT) and KO mice. We found that tonic GABA(A) currents were downregulated in fmr1 KO compared with WT neurons, whereas no significant differences were observed in phasic GABA(A) currents. Molecular biology analysis revealed that the tonic GABA(A) receptor subunits alpha5 and delta were underexpressed in the fmr1 KO mouse subiculum compared with WT. Because the subiculum plays a role in both cognitive functions and epileptic disorders, we propose that altered tonic inhibition in this structure contributes to the behavioral deficits and epileptic activity seen in FXS patients. This conclusion is in line with evidence implicating tonic GABA(A) inhibition in learning and memory.


2008 - Downregulation of tonic GABAA receptor-mediated inhibition in a mouse model of Fragile X syndrome [Abstract in Atti di Convegno]
Curia, Giulia; Papouin, T; Seguela, P; Avoli, M.
abstract

The absence of fragile X mental retardation protein results in the fragile X syndrome (FXS), a common form of mental retardation associated with attention deficit, autistic behavior, and epileptic seizures. The phenotype of FXS is reproduced in fragile X mental retardation 1 (fmr1) knockout (KO) mice that have region-specific altered expression of some gamma-aminobutyric acid (GABA(A)) receptor subunits. However, little is known about the characteristics of GABAergic inhibition in the subiculum of these animals. We employed patch-clamp recordings from subicular pyramidal cells in an in vitro slice preparation. In addition, semiquantitative polymerase chain reaction and western blot experiments were performed on subiculum obtained from wild-type (WT) and KO mice. We found that tonic GABA(A) currents were downregulated in fmr1 KO compared with WT neurons, whereas no significant differences were observed in phasic GABA(A) currents. Molecular biology analysis revealed that the tonic GABA(A) receptor subunits alpha5 and delta were underexpressed in the fmr1 KO mouse subiculum compared with WT. Because the subiculum plays a role in both cognitive functions and epileptic disorders, we propose that altered tonic inhibition in this structure contributes to the behavioral deficits and epileptic activity seen in FXS patients. This conclusion is in line with evidence implicating tonic GABA(A) inhibition in learning and memory.


2008 - Insular excitability and characterisation of the effect of GluR5 receptors in a rodent model of temporal lobe epilepsy [Abstract in Atti di Convegno]
Bortel, A; de Guzman, P; Curia, Giulia; Avoli, M.
abstract

The insular cortex (IC) is involved in the generalization of epileptic discharges in temporal lobe epilepsy (TLE), whereas seizures originating in the IC can mimic the epileptic phenotype seen in some patients with TLE. However, few studies have addressed the changes occurring in the IC in TLE animal models. Here, we analyzed the immunohistochemical and electrophysiological properties of IC networks in non-epileptic control and pilocarpine-treated epileptic rats. Neurons identified with a neuron-specific nuclear protein antibody showed similar counts in the two types of tissue but parvalbumin- and neuropeptide Y-positive interneurons were significantly decreased (parvalbumin, approximately -35%; neuropeptide Y, approximately -38%; P < 0.01) in the epileptic IC. Non-adapting neurons were seen more frequently in the epileptic IC during intracellular injection of depolarizing current pulses. In addition, single-shock electrical stimuli elicited network-driven epileptiform responses in 87% of epileptic and 22% of non-epileptic control neurons (P < 0.01) but spontaneous postsynaptic potentials had similar amplitude, duration and intervals of occurrence in the two groups. Finally, pharmacologically isolated, GABA(A) receptor-mediated inhibitory postsynaptic potentials had more negative reversal potential (P < 0.01) and higher peak conductance (P < 0.05) in epileptic tissue. These data reveal moderate increased network excitability in the IC of pilocarpine-treated epileptic rats. We propose that this limited degree of hyperexcitability originates from the loss of parvalbumin- and neuropeptide Y-positive interneurons that is compensated by an increased drive for GABA(A) receptor-mediated inhibition.


2008 - Opioid-mediated modulation of anterior cingulated cortex networks [Abstract in Atti di Convegno]
Panuccio, G; Curia, Giulia; Colosimo, A; Avoli, M.
abstract

PURPOSE: The anterior cingulate cortex (ACC)--which plays a role in pain, emotions and behavior--can generate epileptic seizures. To date, little is known on the neuronal mechanisms leading to epileptiform synchronization in this structure. Therefore, we investigated the role of excitatory and inhibitory synaptic transmission in epileptiform activity in this cortical area. In addition, since the ACC presents with a high density of opioid receptors, we studied the effect of opioid agonism on epileptiform synchronization in this brain region. METHODS: We used field and intracellular recordings in conjunction with pharmacological manipulations to characterize the epileptiform activity generated by the rat ACC in a brain slice preparation. RESULTS: Bath-application of the convulsant 4-aminopyridine (4AP, 50 microM) induced both brief and prolonged periods of epileptiform synchronization resembling interictal- and ictal-like discharges, respectively. Interictal events could occur more frequently before the onset of ictal activity that was contributed by N-methyl-D-aspartate (NMDA) receptors. Mu-opioid receptor activation abolished 4AP-induced ictal events and markedly reduced the occurrence of the pharmacologically isolated GABAergic synchronous potentials. Ictal discharges were replaced by interictal events during GABAergic antagonism; this GABA-independent activity was influenced by subsequent mu-opioid agonist application. CONCLUSIONS: Our results indicate that both glutamatergic and GABAergic signaling contribute to epileptiform synchronization leading to the generation of electrographic ictal events in the ACC. In addition, mu-opioid receptors appear to modulate both excitatory and inhibitory mechanisms, thus influencing epileptiform synchronization in the ACC.


2008 - The pilocarpine model of temporal lobe epilepsy [Articolo su rivista]
Curia, Giulia; Longo, Daniela; Biagini, Giuseppe; R., Jones; M., Avoli
abstract

Understanding the pathophysiogenesis of temporal lobe epilepsy (TLE) largely rests on the use of modelsof status epilepticus (SE), as in the case of the pilocarpine model. The main features of TLE are: (i) epilepticfoci in the limbic system; (ii) an “initial precipitating injury”; (iii) the so-called “latent period”; and (iv)the presence of hippocampal sclerosis leading to reorganization of neuronal networks. Many of thesecharacteristics can be reproduced in rodents by systemic injection of pilocarpine; in this animal model, SEis followed by a latent period and later by the appearance of spontaneous recurrent seizures (SRSs). Theseprocesses are, however, influenced by experimental conditions such as rodent species, strain, gender, age,doses and routes of pilocarpine administration, as well as combinations with other drugs administeredbefore and/or after SE. In the attempt to limit these sources of variability,we evaluated themethodologicalprocedures used by several investigators in the pilocarpine model; in particular, we have focused on thebehavioural, electrophysiological and histopathological findings obtained with different protocols. Weaddressed the various experimental approaches published to date, by comparing mortality rates, onset ofSRSs, neuronal damage, and network reorganization. Based on the evidence reviewed here, we proposethat the pilocarpine model can be a valuable tool to investigate the mechanisms involved in TLE, and evenmore so when standardized to reduce mortality at the time of pilocarpine injection, differences in latentperiod duration, variability in the lesion extent, and SRS frequency.


2007 - Altered GABA signalling in a mouse model of fragile X syndrome. [Abstract in Atti di Convegno]
Curia, Giulia; Papouin, T; Seguela, P; Avoli, M.
abstract

The absence of fragile X mental retardation protein results in the fragile X syndrome (FXS), a common form of mental retardation associated with attention deficit, autistic behavior, and epileptic seizures. The phenotype of FXS is reproduced in fragile X mental retardation 1 (fmr1) knockout (KO) mice that have region-specific altered expression of some gamma-aminobutyric acid (GABA(A)) receptor subunits. However, little is known about the characteristics of GABAergic inhibition in the subiculum of these animals. We employed patch-clamp recordings from subicular pyramidal cells in an in vitro slice preparation. In addition, semiquantitative polymerase chain reaction and western blot experiments were performed on subiculum obtained from wild-type (WT) and KO mice. We found that tonic GABA(A) currents were downregulated in fmr1 KO compared with WT neurons, whereas no significant differences were observed in phasic GABA(A) currents. Molecular biology analysis revealed that the tonic GABA(A) receptor subunits alpha5 and delta were underexpressed in the fmr1 KO mouse subiculum compared with WT. Because the subiculum plays a role in both cognitive functions and epileptic disorders, we propose that altered tonic inhibition in this structure contributes to the behavioral deficits and epileptic activity seen in FXS patients. This conclusion is in line with evidence implicating tonic GABA(A) inhibition in learning and memory.


2007 - Altered GABAergic system in a mouse model of fragile X syndrome [Abstract in Rivista]
Curia, Giulia; Papouin, T; Seguela, P; Avoli, M.
abstract

fragile X


2007 - Antiepileptic drugs and muscarinic receptor-dependent excitation in the rat subiculum. [Articolo su rivista]
M., D'Antuono; H., Kawasaki; C., Palmieri; Curia, Giulia; Biagini, Giuseppe; M., Avoli
abstract

Field and intracellular recordings were made in an in vitro slice preparation to establish whether the antiepileptic drugs topiramate andlamotrigine modulate cholinergic excitation in the rat subiculum. Bath application of carbachol (CCh, 70e100 mM) induced: (i) spontaneousand synchronous field oscillations (duration ¼ up to 7 s) that were mirrored by intracellular depolarizations with rhythmic action potentialbursts; and (ii) depolarizing plateau potentials (DPPs, duration ¼ up to 2.5 s) associated with action potential discharge in response to brief(50e100 ms) intracellular depolarizing current pulses. Ionotropic glutamatergic receptor antagonists abolished the field oscillations withoutinfluencing DPPs, while atropine (1 mM) markedly reduced both types of activity. Topiramate (10e100 mM, n ¼ 8e13 slices) or lamotrigine(50e400 mM, n ¼ 3e12) decreased in a dose-dependent manner, and eventually abolished, CCh-induced field oscillations. During topiramateapplication, these effects were accompanied by marked DPP reduction. When these antiepileptic drugs were tested on DPPs recorded in thepresence of CCh þ ionotropic glutamatergic and GABA receptor antagonists, only topiramate reduced DPPs (n ¼ 5e19/dose; IC50 ¼ 18 mM,n ¼ 48). Similar effects were induced by topiramate during metabotropic glutamate receptor antagonism (n ¼ 5), which did not influenceDPPs. Thus, topiramate and lamotrigine reduce CCh-induced epileptiform synchronization in the rat subiculum but only topiramate is effectivein controlling DPPs. We propose that muscarinic receptor-mediated excitation represents a target for the action of some antiepileptic drugs suchas topiramate.


2007 - Phosphorylation of sodium channels mediated by protein kinase-C modulates inhibition by topiramate of tetrodotoxin-sensitive transient sodium current [Articolo su rivista]
Curia, Giulia; Aracri, P; Colombo, E; Scalmani, P; Mantegazza, M; Avanzini, G; Franceschetti, S.
abstract

Topiramate is a novel anticonvulsant known to modulate the activity of several ligand- and voltage-gated ion channels in neurons. The mechanism of action of topiramate, at a molecular level, is still unclear, but the phosphorylation state of the channel/receptor seems to be a factor that is able to influence its activity. We investigated the consequences of phosphorylation of the sodium channel on the effect of topiramate on tetrodotoxin (TTX)-sensitive transient Na(+) current (I(NaT)).


2007 - Zn(2+) slows down Ca(V)3.3 gating kinetics: implications for thalamocortical activity [Articolo su rivista]
Cataldi, M; Lariccia, V; Marzaioli, V; Cavaccini, A; Curia, Giulia; Viggiano, D; Canzoniero, L. M. T; di Renzo, G; Avoli, M; Annunziato, L.
abstract

We employed whole cell patch-clamp recordings to establish the effect of Zn(2+) on the gating the brain specific, T-type channel isoform Ca(V)3.3 expressed in HEK-293 cells. Zn(2+) (300 microM) modified the gating kinetics of this channel without influencing its steady-state properties. When inward Ca(2+) currents were elicited by step depolarizations at voltages above the threshold for channel opening, current inactivation was significantly slowed down while current activation was moderately affected. In addition, Zn(2+) slowed down channel deactivation but channel recovery from inactivation was only modestly changed. Zn(2+) also decreased whole cell Ca(2+) permeability to 45% of control values. In the presence of Zn(2+), Ca(2+) currents evoked by mock action potentials were more persistent than in its absence. Furthermore, computer simulation of action potential generation in thalamic reticular cells performed to model the gating effect of Zn(2+) on T-type channels (while leaving the kinetic parameters of voltage-gated Na(+) and K(+) unchanged) revealed that Zn(2+) increased the frequency and the duration of burst firing, which is known to depend on T-type channel activity. In line with this finding, we discovered that chelation of endogenous Zn(2+) decreased the frequency of occurrence of ictal-like epileptiform discharges in rat thalamocortical slices perfused with medium containing the convulsant 4-aminopyridine (50 microM). These data demonstrate that Zn(2+) modulates Ca(V)3.3 channel gating thus leading to increased neuronal excitability. We also propose that endogenous Zn(2+) may have a role in controlling thalamocortical oscillations.


2006 - 4-Aminopyridine induces network-driven bursting in subiculum minislices in an animal model of temporal lobe epilepsy [Abstract in Rivista]
Curia, Giulia; Benini, R; Avoli, M.
abstract

subiculum


2006 - Increased sensitivity of the alpha-2 neuronal nicotinic receptor causes familial epilepsy with nocturnal wandering and ictal fear [Abstract in Rivista]
Marini, C; Aridon, P; Di Resta, C; Brilli, E; De Fusco, M; Politi, F; Parrini, E; Manfredi, I; Pisano, T; Pruna, D; Curia, Giulia; Cianchetti, C; Pasqualetti, M; Becchetti, A; Guerrini, R; Casari, G.
abstract

nicotinic receptor


2006 - Increased sensitivity of the neuronal nicotinic receptor alpha 2 subunit causes familial epilepsy with nocturnal wandering and ictal fear [Articolo su rivista]
Aridon, Paolo; Marini, Carla; Di Resta, Chiara; Brilli, Elisa; De Fusco, Maurizio; Politi, Fausta; Parrini, Elena; Manfredi, Irene; Pisano, Tiziana; Pruna, Dario; Curia, Giulia; Cianchetti, Carlo; Pasqualetti, Massimo; Becchetti, Andrea; Guerrini, Renzo; Casari, Giorgio
abstract

Sleep has traditionally been recognized as a precipitating factor for some forms of epilepsy, although differential diagnosis between some seizure types and parasomnias may be difficult. Autosomal dominant frontal lobe epilepsy is characterized by nocturnal seizures with hyperkinetic automatisms and poorly organized stereotyped movements and has been associated with mutations of the alpha 4 and beta 2 subunits of the neuronal nicotinic acetylcholine receptor. We performed a clinical and molecular genetic study of a large pedigree segregating sleep-related epilepsy in which seizures are associated with fear sensation, tongue movements, and nocturnal wandering, closely resembling nightmares and sleep walking. We identified a new genetic locus for familial sleep-related focal epilepsy on chromosome 8p12.3-8q12.3. By sequencing the positional candidate neuronal cholinergic receptor alpha 2 subunit gene (CHRNA2), we detected a heterozygous missense mutation, I279N, in the first transmembrane domain that is crucial for receptor function. Whole-cell recordings of transiently transfected HEK293 cells expressing either the mutant or the wild-type receptor showed that the new CHRNA2 mutation markedly increases the receptor sensitivity to acetylcholine, therefore indicating that the nicotinic alpha 2 subunit alteration is the underlying cause. CHRNA2 is the third neuronal cholinergic receptor gene to be associated with familial sleep-related epilepsies. Compared with the CHRNA4 and CHRNB2 mutations reported elsewhere, CHRNA2 mutations cause a more complex and finalized ictal behavior.


2006 - Layer-specific properties of the persistent sodium current in sensorimotor cortex [Articolo su rivista]
Aracri, P; Colombo, E; Mantegazza, M; Scalmani, P; Curia, Giulia; Avanzini, G; Franceschetti, S.
abstract

We evaluated the characteristics of the persistent sodium current (I(NaP)) in pyramidal neurons of layers II/III and V in slices of rat sensorimotor cortex using whole cell patch-clamp recordings. In both layers, I(NaP) began activating around -60 mV and was half-activated at -43 mV. The I(NaP) peak amplitude and density were significantly higher in layer V. The voltage-dependent I(NaP) steady-state inactivation occurred at potentials that were significantly more positive in layer V (V(1/2): -42.3 +/- 1.1 mV) than in layer II/III (V(1/2): -46.8 +/- 1.6 mV). In both layers, a current fraction corresponding to about 25% of the maximal peak amplitude did not inactivate. The time course of I(NaP) inactivation and recovery from inactivation could be fitted with a biexponential function. In layer V pyramidal neurons the faster time constant of development of inactivation had variable values, ranging from 158.0 to 1,133.8 ms, but it was on average significantly slower than that in layer II/III (425.9 +/- 80.5 vs. 145.8 +/- 18.2 ms). In both layers, I(NaP) did not completely inactivate even with very long conditioning depolarizations (40 s at -10 mV). Recovery from inactivation was similar in the two layers. Layer V intrinsically bursting and regular spiking nonadapting neurons showed particularly prolonged depolarized plateau potentials when Ca2+ and K+ currents were blocked and slower early phase of I(NaP) development of inactivation. The biexponential kinetics characterizing the time-dependent inactivation of I(NaP) in layers II/III and V indicates a complex inactivating process that is incomplete, allowing a residual "persistent" current fraction that does not inactivate. Moreover, our data indicate that I(NaP) has uneven inactivation properties in pyramidal neurons of different layers of rat sensorimotor cortex. The higher current density, the rightward shifted voltage dependency of inactivation as well the slower kinetics of inactivation characterizing I(NaP) in layer V with respect to layer II/III pyramidal neurons may play a significant role in their ability to fire recurrent action potential bursts, as well in the high susceptibility to generate epileptic events.


2006 - Underexpression of α5 and δ subunits of tonic GABAA receptors in the subiculum of fmr1 knockout mice [Abstract in Rivista]
Papouin, T; Curia, Giulia; Seguela, P; Avoli, M.
abstract

tonic GABA


2005 - Neuronal nicotinic receptors and nocturnal frontal lobe epilepsy. [Abstract in Atti di Convegno]
Becchetti, A; Curia, Giulia; Consonni, S.
abstract

Carbamazepine (5H-dibenz[b,f]azepine-5-carboxamide) and oxcarbazepine (10,11-dihydro-10-oxo-5H-dibenz[b,f]azepine-5-carboxamide) are widely used for the treatment of partial epilepsy. Recent work indicates that these drugs, in addition to targeting voltage-gated Na(+) channels, can modulate ligand-gated channels. These compounds appear to be particularly effective for treatment of nocturnal frontal lobe epilepsy, which can be caused by mutant neuronal nicotinic receptors. We compared the effects of carbamazepine and oxcarbazepine on heteromeric nicotinic receptors to better understand the underlying mechanism of the effect of these drugs in epileptic patients. Receptors were expressed in cell lines and studied by patch-clamp methods at -60 mV. For alpha2beta4 receptors activated with 100 microM nicotine, IC(50) for carbamazepine was 49 microM. Receptors in which alpha2 was substituted with alpha2-I279 N, linked to autosomal dominant nocturnal frontal lobe epilepsy, had an IC(50) of 21 microM. For oxcarbazepine, the IC(50) was larger than 500 microM for wild-type receptors and approximately 100 microM for mutant receptors. A similar inhibition was observed in the presence of 10 microM nicotine, indicating a non-competitive mechanism. The monohydroxy derivative (MHD) of oxcarbazepine, clinically the most relevant compound, was tested on both alpha2beta4 and alpha4beta2 receptors, to obtain a broader view of its possible physiological effects. At the typical concentration present in blood (100 microM), MHD produced an approximate 40% channel block on alpha4beta2, but no significant effect on alpha2beta4 receptors. Oxcarbazepine and MHD retarded the channel deactivation, suggesting that these compounds produce open channel block. These results may explain the particular efficacy of these drugs in nocturnal frontal lobe epilepsy.


2004 - Protein-kinase C-dependent phosphorylation inhibits the effect of the antiepileptic drug topiramate on the persistent fraction of sodium currents [Articolo su rivista]
Curia, Giulia; Aracri, P; Sancini, G; Mantegazza, M; Avanzini, G; Franceschetti, S.
abstract

We investigated the interference of protein-kinase C (PKC)-dependent Na(+) channel phosphorylation on the inhibitory effect that the antiepileptic drug topiramate (TPM) has on persistent Na(+) currents (I(NaP)) by making whole cell patch-clamp and intracellular recordings of rat sensorimotor cortex neurons. The voltage-dependent activation of I(NaP) was significantly shifted in the hyperpolarizing direction when PKC was activated by 1-oleoyl-2-acetyl-sn-glycerol (OAG). TPM reduced the peak amplitude of I(NaP), but it did not counteract the OAG-induced shift in I(NaP) activation. Firing property experiments showed that the firing threshold was lowered by OAG. TPM was unable to counteract this effect, which may be due to OAG-dependent enhancement of the contribution of subthreshold I(NaP). These data suggest that PKC activation may limit the effect of the anticonvulsant TPM on the persistent fraction of Na(+) currents. The channel phosphorylation that may occur in cortical neurons as a result of physiological or pathological (e.g. epileptic) events can modulate the action of TPM on Na(+) currents.


2004 - Resveratrol derivatives and their role as potassium channels modulators [Articolo su rivista]
Orsini, F; Verotta, L; Lecchi, M; Restano, R; Curia, Giulia; Redaelli, E; Wanke, E.
abstract

A series of stilbenoid analogues of resveratrol (trans-3,4',5-trihydroxystilbene) with a stilbenic or a bibenzylic skeleton have been prepared by partial synthesis from resveratrol and dihydroresveratrol. The synthesized compounds have been evaluated for their ability to modulate voltage-gated channels.


2004 - The biophysical properties of beta2-V287L mutant neuronal nicotinic receptors linked to ADNFLE [Abstract in Rivista]
Becchetti, A; Curia, Giulia; Rampoldi, L; Casari, G; Wanke, E.
abstract

The biophysical properties of beta2-V287L mutant neuronal nicotinic receptors linked to ADNFLE


2003 - Depolarization differentially affects the secretory and migratory properties of two cell lines of immortalized luteinizing hormone-releasing hormone (LHRH) neurons [Articolo su rivista]
Pimpinelli, Federica; Redaelli, Elisa; Restano Cassulini, Rita; Curia, Giulia; Giacobini, Paolo; Cariboni, Anna; Wanke, Enzo; Bondiolotti, Gian Pietro; Piva, Flavio; Maggi, Roberto
abstract

In this report we studied and compared the biochemical and the electrophysiological characteristics of two cell lines (GT1-7 and GN11) of immortalized mouse LHRH-expressing neurons and the correlation with their maturational stage and migratory activity. In fact, previous results indicated that GN11, but not GT1-7, cells exhibit an elevated motility in vitro. The results show that the two cell lines differ in terms of immunoreactivity for tyrosine hydroxylase and nestin as well as of production and release of 3,4-dihydroxyphenylalanine (DOPA) and of intracellular distribution and release of the LHRH. Patch-clamp recordings in GN11 cells, reveal the presence of a single inward rectifier K+ current indicative of an immature neuronal phenotype (neither firing nor electrical activity). In contrast, as known from previous studies, GT1-7 cells show the characteristics of mature LHRH neurons with a high electrical activity characterized by spontaneous firing and excitatory postsynaptic potentials. K+-induced depolarization induces in GT1-7 cells, but not in GN11 cells, a strong increase in the release of LHRH in the culture medium. However, depolarization of GN11 cells significantly decreases their chemomigratory response. In conclusion, these results indicate that GT1-7 and GN11 cells show different biochemical and electrophysiological characteristics and are representative of mature and immature LHRH neurons, respectively. The early stage of maturation of GN11 cells, as well as the low electrical activity detected in these cells, appears to correlate with their migratory activity in vitro.


2003 - Na+-activated K+ current contributes to postexcitatory hyperpolarization in neocortical intrinsically bursting neurons [Articolo su rivista]
Franceschetti, Silvana; Lavazza, Tatiana; Curia, Giulia; Aracri, Patrizia; Panzica, Ferruccio; Sancini, Giulio; Avanzini, Giuliano; Magistretti, Jacopo
abstract

The ionic mechanisms underlying the termination of action-potential (AP) bursts and postburst afterhyperpolarization (AHP) in intrinsically bursting (IB) neocortical neurons were investigated by performing intracellular recordings in thin slices of rat sensorimotor cortex. The blockade of Ca(2+)-activated K(+) currents enhanced postburst depolarizing afterpotentials, but had inconsistent and minor effects on the amplitude and duration of AHPs. On the contrary, experimental conditions resulting in reduction of voltage-dependent Na(+) entry into the cells caused a significant decrease of AHP amplitude. Slice perfusion with a modified artificial cerebrospinal fluid in which LiCl (40 mM) partially replaced NaCl had negligible effects on the properties of individual APs, whereas it consistently increased burst length and led to an approximately 30% reduction in the amplitude of AHPs following individual bursts or short trains of stimulus-induced APs. Experiments performed by partially replacing Na(+) ions with choline revealed a comparable reduction in AHP amplitude associated with an inhibition of bursting activity. Moreover, in voltage-clamp experiments carried out in both in situ and acutely isolated neurons, partial substitution of extracellular NaCl with LiCl significantly and reversibly reduced the amplitude of K(+) currents evoked by depolarizing stimuli above-threshold for Na(+)-current activation. The above effect of Na(+)-to-Li(+) substitution was not seen when voltage-gated Na(+) currents were blocked with TTX, indicating the presence of a specific K(+)-current component activated by voltage-dependent Na(+) (but not Li(+)) influx. The above findings suggest that a Na(+)-activated K(+) current recruited by the Na(+) entry secondary to burst discharge significantly contributes to AHP generation and the maintenance of rhythmic burst recurrence during sustained depolarizations in neocortical IB neurons.


2003 - Nicotinic acetylcholine receptors and nocturnal frontal lobe epilepsy [Abstract in Atti di Convegno]
Becchetti, A; Curia, Giulia; Wanke, E; Rampoldi, L; Casari, G.
abstract

Sleep has traditionally been recognized as a precipitating factor for some forms of epilepsy, although differential diagnosis between some seizure types and parasomnias may be difficult. Autosomal dominant frontal lobe epilepsy is characterized by nocturnal seizures with hyperkinetic automatisms and poorly organized stereotyped movements and has been associated with mutations of the alpha 4 and beta 2 subunits of the neuronal nicotinic acetylcholine receptor. We performed a clinical and molecular genetic study of a large pedigree segregating sleep-related epilepsy in which seizures are associated with fear sensation, tongue movements, and nocturnal wandering, closely resembling nightmares and sleep walking. We identified a new genetic locus for familial sleep-related focal epilepsy on chromosome 8p12.3-8q12.3. By sequencing the positional candidate neuronal cholinergic receptor alpha 2 subunit gene (CHRNA2), we detected a heterozygous missense mutation, I279N, in the first transmembrane domain that is crucial for receptor function. Whole-cell recordings of transiently transfected HEK293 cells expressing either the mutant or the wild-type receptor showed that the new CHRNA2 mutation markedly increases the receptor sensitivity to acetylcholine, therefore indicating that the nicotinic alpha 2 subunit alteration is the underlying cause. CHRNA2 is the third neuronal cholinergic receptor gene to be associated with familial sleep-related epilepsies. Compared with the CHRNA4 and CHRNB2 mutations reported elsewhere, CHRNA2 mutations cause a more complex and finalized ictal behavior.


2002 - Contribution of Na+-activated K+ current to post-excitatory hyperpolarisation in neocortical IB neurons [Abstract in Atti di Convegno]
Franceschetti, S; Curia, Giulia; Aracri, P; Lavazza, T; Magistretti, J; Panzica, F; Sancini, G; Avanzini, G.
abstract

We evaluated the characteristics of the persistent sodium current (I(NaP)) in pyramidal neurons of layers II/III and V in slices of rat sensorimotor cortex using whole cell patch-clamp recordings. In both layers, I(NaP) began activating around -60 mV and was half-activated at -43 mV. The I(NaP) peak amplitude and density were significantly higher in layer V. The voltage-dependent I(NaP) steady-state inactivation occurred at potentials that were significantly more positive in layer V (V(1/2): -42.3 +/- 1.1 mV) than in layer II/III (V(1/2): -46.8 +/- 1.6 mV). In both layers, a current fraction corresponding to about 25% of the maximal peak amplitude did not inactivate. The time course of I(NaP) inactivation and recovery from inactivation could be fitted with a biexponential function. In layer V pyramidal neurons the faster time constant of development of inactivation had variable values, ranging from 158.0 to 1,133.8 ms, but it was on average significantly slower than that in layer II/III (425.9 +/- 80.5 vs. 145.8 +/- 18.2 ms). In both layers, I(NaP) did not completely inactivate even with very long conditioning depolarizations (40 s at -10 mV). Recovery from inactivation was similar in the two layers. Layer V intrinsically bursting and regular spiking nonadapting neurons showed particularly prolonged depolarized plateau potentials when Ca2+ and K+ currents were blocked and slower early phase of I(NaP) development of inactivation. The biexponential kinetics characterizing the time-dependent inactivation of I(NaP) in layers II/III and V indicates a complex inactivating process that is incomplete, allowing a residual "persistent" current fraction that does not inactivate. Moreover, our data indicate that I(NaP) has uneven inactivation properties in pyramidal neurons of different layers of rat sensorimotor cortex. The higher current density, the rightward shifted voltage dependency of inactivation as well the slower kinetics of inactivation characterizing I(NaP) in layer V with respect to layer II/III pyramidal neurons may play a significant role in their ability to fire recurrent action potential bursts, as well in the high susceptibility to generate epileptic events.


2002 - Isolation of a long-lasting eag-related gene-type K+ current in MMQ lactotrophs and its accommodating role during slow firing and prolactin release [Articolo su rivista]
Lecchi, Marzia; Redaelli, Elisa; Rosati, Barbara; Gurrola, Georgina; Florio, Tullio; Crociani, Olivia; Curia, Giulia; Cassulini, Rita Restano; Masi, Alessio; Arcangeli, Annarosa; Olivotto, Massimo; Schettini, Gennaro; Possani, Lourival D; Wanke, Enzo
abstract

Native rat lactotrophs express thyrotrophin-releasing hormone-dependent K+ currents consisting of fast and slow deactivating components that are both sensitive to the class III anti-arrhythmic drugs that block the eag-related gene (ERG) K+ current (I(ERG)). Here we describe in MMQ prolactin-releasing pituitary cells the isolation of the slowly deactivating long-lasting component (I(ERGS)), which, unlike the fast component (I(ERGF)), is insensitive to verapamil 2 microm but sensitive to a novel scorpion toxin (ErgTx-2) that hardly affects I(ERGF). The time constants of I(ERGS) activation, deactivation, and recovery from inactivation are more than one order of magnitude greater than in I(ERGF), and the voltage-dependent inactivation is left-shifted by approximately 25 mV. The very slow MMQ firing frequency (approximately 0.2 Hz) investigated in perforated patch is increased approximately four times by anti-arrhythmic agents, by ErgTx-2, and by the abrupt I(ERGS) deactivation. Prolactin secretion in the presence of anti-arrhythmics is three- to fourfold higher in comparison with controls. We provide evidence from I(ERGS) and I(ERGF) simulations in a firing model cell to indicate that only I(ERGS) has an accommodating role during the experimentally observed very slow firing. Thus, we suggest that I(ERGS) potently modulates both firing and prolactin release in lactotroph cells.


2002 - PKC-dependent channel phosphorylation modulates the effect of the anticonvulsant topiramate (TPM) on sodium current. [Abstract in Atti di Convegno]
Aracri, P; Curia, Giulia; Sancini, G; Franceschetti, S; Spreafico, R; Mantegazza, M; Avanzini, G.
abstract

We investigated the interference of protein-kinase C (PKC)-dependent Na(+) channel phosphorylation on the inhibitory effect that the antiepileptic drug topiramate (TPM) has on persistent Na(+) currents (I(NaP)) by making whole cell patch-clamp and intracellular recordings of rat sensorimotor cortex neurons. The voltage-dependent activation of I(NaP) was significantly shifted in the hyperpolarizing direction when PKC was activated by 1-oleoyl-2-acetyl-sn-glycerol (OAG). TPM reduced the peak amplitude of I(NaP), but it did not counteract the OAG-induced shift in I(NaP) activation. Firing property experiments showed that the firing threshold was lowered by OAG. TPM was unable to counteract this effect, which may be due to OAG-dependent enhancement of the contribution of subthreshold I(NaP). These data suggest that PKC activation may limit the effect of the anticonvulsant TPM on the persistent fraction of Na(+) currents. The channel phosphorylation that may occur in cortical neurons as a result of physiological or pathological (e.g. epileptic) events can modulate the action of TPM on Na(+) currents.


2001 - ERG-like current is expressed in GT1-7 hypothalamic neurons. [Abstract in Atti di Convegno]
Restano Cassulini, R; Lecchi, M; Redaelli, E; Curia, Giulia; Rosati, B; Maggi, R; Wanke, E.
abstract

In this report we studied and compared the biochemical and the electrophysiological characteristics of two cell lines (GT1-7 and GN11) of immortalized mouse LHRH-expressing neurons and the correlation with their maturational stage and migratory activity. In fact, previous results indicated that GN11, but not GT1-7, cells exhibit an elevated motility in vitro. The results show that the two cell lines differ in terms of immunoreactivity for tyrosine hydroxylase and nestin as well as of production and release of 3,4-dihydroxyphenylalanine (DOPA) and of intracellular distribution and release of the LHRH. Patch-clamp recordings in GN11 cells, reveal the presence of a single inward rectifier K+ current indicative of an immature neuronal phenotype (neither firing nor electrical activity). In contrast, as known from previous studies, GT1-7 cells show the characteristics of mature LHRH neurons with a high electrical activity characterized by spontaneous firing and excitatory postsynaptic potentials. K+-induced depolarization induces in GT1-7 cells, but not in GN11 cells, a strong increase in the release of LHRH in the culture medium. However, depolarization of GN11 cells significantly decreases their chemomigratory response. In conclusion, these results indicate that GT1-7 and GN11 cells show different biochemical and electrophysiological characteristics and are representative of mature and immature LHRH neurons, respectively. The early stage of maturation of GN11 cells, as well as the low electrical activity detected in these cells, appears to correlate with their migratory activity in vitro.


2001 - Isolation of a long-lasting toxin-sensitive and verapamil-insensitive erg-type K+ current in MMQ rat lactotrophs [Abstract in Atti di Convegno]
Lecchi, M; Redaelli, E; Curia, Giulia; Restano Cassulini, R; Rosati, B; Gurrola, G; Crociani, O; Masi, A; Arcangeli, A; Olivotto, M; Possani, Ld; Wanke, E.
abstract

Native rat lactotrophs express thyrotrophin-releasing hormone-dependent K+ currents consisting of fast and slow deactivating components that are both sensitive to the class III anti-arrhythmic drugs that block the eag-related gene (ERG) K+ current (I(ERG)). Here we describe in MMQ prolactin-releasing pituitary cells the isolation of the slowly deactivating long-lasting component (I(ERGS)), which, unlike the fast component (I(ERGF)), is insensitive to verapamil 2 microm but sensitive to a novel scorpion toxin (ErgTx-2) that hardly affects I(ERGF). The time constants of I(ERGS) activation, deactivation, and recovery from inactivation are more than one order of magnitude greater than in I(ERGF), and the voltage-dependent inactivation is left-shifted by approximately 25 mV. The very slow MMQ firing frequency (approximately 0.2 Hz) investigated in perforated patch is increased approximately four times by anti-arrhythmic agents, by ErgTx-2, and by the abrupt I(ERGS) deactivation. Prolactin secretion in the presence of anti-arrhythmics is three- to fourfold higher in comparison with controls. We provide evidence from I(ERGS) and I(ERGF) simulations in a firing model cell to indicate that only I(ERGS) has an accommodating role during the experimentally observed very slow firing. Thus, we suggest that I(ERGS) potently modulates both firing and prolactin release in lactotroph cells.


2001 - Modulating effect of PKC-dependent channel phosphorylation on sodium current inhibition operated by the antiepileptic drug topiramate. [Abstract in Atti di Convegno]
Curia, Giulia; Aracri, P; Sancini, G; Franceschetti, S; Avanzini, G.
abstract

BACKGROUND AND PURPOSE: Topiramate is a novel anticonvulsant known to modulate the activity of several ligand- and voltage-gated ion channels in neurons. The mechanism of action of topiramate, at a molecular level, is still unclear, but the phosphorylation state of the channel/receptor seems to be a factor that is able to influence its activity. We investigated the consequences of phosphorylation of the sodium channel on the effect of topiramate on tetrodotoxin (TTX)-sensitive transient Na(+) current (I(NaT)). EXPERIMENTAL APPROACH: I(NaT) was recorded in dissociated neurons of rat sensorimotor cortex using whole-cell patch-clamp configuration. KEY RESULTS: We found that topiramate (100 microM) significantly shifted the steady-state I(NaT) inactivation curve in a hyperpolarized direction. In neurons pre-treated with a PKC-activator, 1-oleoyl-2-acetyl-sn-glycerol (OAG; 2 microM), the net effect of topiramate on steady-state I(NaT) inactivation was significantly decreased. In addition, OAG also slightly shifted the I(NaT) activation curve in a hyperpolarized direction, while perfusion with topiramate had no effect on the parameters of I(NaT) activation. CONCLUSIONS AND IMPLICATIONS: These data show that PKC-activation can modulate the effect of topiramate on I(NaT). This suggests that channel phosphorylation in physiological or pathological conditions (such as epiliepsy), can alter the action of topiramate on sodium currents.


2000 - ERG potassium current in hypothalamic LHRH-secreting neurons [Abstract in Rivista]
Rosati, B; Lecchi, M; Curia, Giulia; Redaelli, E; Restano Cassulini, R; Arcangeli, A; Olivotto, M; Wanke, E.
abstract

ERG potassium current in hypothalamic LHRH-secreting neurons


2000 - Tamoxifen blocks ERG potassium channels in DRG X neuroblastoma F11 cells. [Abstract in Rivista]
Lecchi, M; Rosati, B; Becchetti, A; Redaelli, E; Curia, Giulia; Restano Cassulini, R; Aracri, P; Colombo, E; Gullo, F; Arcangeli, A; Olivotto, M; Wanke, E.
abstract

Italian Society of Physiology


1999 - A novel erg-like potassium channel in pituitary cells [Abstract in Atti di Convegno]
Rosati, B; Cuccuru, D; Lecchi, M; Redaelli, E; Restano, R; Curia, Giulia; Anselmi, A; Arcangeli, A; Crociani, O; Olivotto, M; Wanke, E.
abstract

In this report we studied and compared the biochemical and the electrophysiological characteristics of two cell lines (GT1-7 and GN11) of immortalized mouse LHRH-expressing neurons and the correlation with their maturational stage and migratory activity. In fact, previous results indicated that GN11, but not GT1-7, cells exhibit an elevated motility in vitro. The results show that the two cell lines differ in terms of immunoreactivity for tyrosine hydroxylase and nestin as well as of production and release of 3,4-dihydroxyphenylalanine (DOPA) and of intracellular distribution and release of the LHRH. Patch-clamp recordings in GN11 cells, reveal the presence of a single inward rectifier K+ current indicative of an immature neuronal phenotype (neither firing nor electrical activity). In contrast, as known from previous studies, GT1-7 cells show the characteristics of mature LHRH neurons with a high electrical activity characterized by spontaneous firing and excitatory postsynaptic potentials. K+-induced depolarization induces in GT1-7 cells, but not in GN11 cells, a strong increase in the release of LHRH in the culture medium. However, depolarization of GN11 cells significantly decreases their chemomigratory response. In conclusion, these results indicate that GT1-7 and GN11 cells show different biochemical and electrophysiological characteristics and are representative of mature and immature LHRH neurons, respectively. The early stage of maturation of GN11 cells, as well as the low electrical activity detected in these cells, appears to correlate with their migratory activity in vitro.


1999 - ERG potassium current in hypotalamic LHRH-secreting neurons [Abstract in Atti di Convegno]
Rosati, B; Lecchi, M; Curia, Giulia; Redaelli, E; Restano Cassulini, R; Arcangeli, A; Crociani, O; Olivotto, M; Wanke, E.
abstract

In this report we studied and compared the biochemical and the electrophysiological characteristics of two cell lines (GT1-7 and GN11) of immortalized mouse LHRH-expressing neurons and the correlation with their maturational stage and migratory activity. In fact, previous results indicated that GN11, but not GT1-7, cells exhibit an elevated motility in vitro. The results show that the two cell lines differ in terms of immunoreactivity for tyrosine hydroxylase and nestin as well as of production and release of 3,4-dihydroxyphenylalanine (DOPA) and of intracellular distribution and release of the LHRH. Patch-clamp recordings in GN11 cells, reveal the presence of a single inward rectifier K+ current indicative of an immature neuronal phenotype (neither firing nor electrical activity). In contrast, as known from previous studies, GT1-7 cells show the characteristics of mature LHRH neurons with a high electrical activity characterized by spontaneous firing and excitatory postsynaptic potentials. K+-induced depolarization induces in GT1-7 cells, but not in GN11 cells, a strong increase in the release of LHRH in the culture medium. However, depolarization of GN11 cells significantly decreases their chemomigratory response. In conclusion, these results indicate that GT1-7 and GN11 cells show different biochemical and electrophysiological characteristics and are representative of mature and immature LHRH neurons, respectively. The early stage of maturation of GN11 cells, as well as the low electrical activity detected in these cells, appears to correlate with their migratory activity in vitro.