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Nelson JA, Knupp KG. Lennox-Gastaut Syndrome: Current Treatments, Novel Therapeutics, and Future Directions. Neurotherapeutics 2023; 20:1255-1262. [PMID: 37353676 PMCID: PMC10480363 DOI: 10.1007/s13311-023-01397-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2023] [Indexed: 06/25/2023] Open
Abstract
Lennox-Gastaut syndrome is a severe drug-resistant developmental and epileptic encephalopathy with slow spike and wave on EEG (DEE-SSW) composing about 1-2% of epilepsy patients. Seizures in DEE-SSW are caused by a variety of etiologies, and there is a large unmet treatment need as seizures are usually treatment-resistant and individuals are often unable to function independently. The updated definition by the International League Against Epilepsy has established formal diagnostic criteria allowing for more uniform diagnosis. This article provides a review of typical medication management and treatment strategies, including new and developing surgical approaches. Future directions in treatment include expanding genetic testing with the potential for gene therapy and continuously improving surgical options with the goal to prevent progression to DEE-SSW.
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Affiliation(s)
- Julie A Nelson
- Section of Child Neurology, Children's Hospital Colorado, Anschutz School of Medicine, University of Colorado, Aurora, CO, USA.
| | - Kelly G Knupp
- Section of Child Neurology, Children's Hospital Colorado, Anschutz School of Medicine, University of Colorado, Aurora, CO, USA
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Sills GJ. Pharmacological diversity amongst approved and emerging antiseizure medications for the treatment of developmental and epileptic encephalopathies. Ther Adv Neurol Disord 2023; 16:17562864231191000. [PMID: 37655228 PMCID: PMC10467199 DOI: 10.1177/17562864231191000] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 07/13/2023] [Indexed: 09/02/2023] Open
Abstract
Developmental and epileptic encephalopathies (DEEs) are rare neurodevelopmental disorders characterised by early-onset and often intractable seizures and developmental delay/regression, and include Dravet syndrome and Lennox-Gastaut syndrome (LGS). Rufinamide, fenfluramine, stiripentol, cannabidiol and ganaxolone are antiseizure medications (ASMs) with diverse mechanisms of action that have been approved for treating specific DEEs. Rufinamide is thought to suppress neuronal hyperexcitability by preventing the functional recycling of voltage-gated sodium channels from the inactivated to resting state. It is licensed for adjunctive treatment of seizures associated with LGS. Fenfluramine increases extracellular serotonin levels and may reduce seizures via activation of specific serotonin receptors and positive modulation of the sigma-1 receptor. Fenfluramine is licensed for adjunctive treatment of seizures associated with Dravet syndrome and LGS. Stiripentol is a positive allosteric modulator of type-A gamma-aminobutyric acid (GABAA) receptors. As a broad-spectrum inhibitor of cytochrome P450 enzymes, its antiseizure effects may additionally arise through pharmacokinetic interactions with co-administered ASMs. Stiripentol is licensed for treating seizures associated with Dravet syndrome in patients taking clobazam and/or valproate. The mechanism(s) of action of cannabidiol remains largely unclear although multiple targets have been proposed, including transient receptor potential vanilloid 1, G protein-coupled receptor 55 and equilibrative nucleoside transporter 1. Cannabidiol is licensed as adjunctive treatment in conjunction with clobazam for seizures associated with Dravet syndrome and LGS, and as adjunctive treatment of seizures associated with tuberous sclerosis complex. Like stiripentol, ganaxolone is a positive allosteric modulator at GABAA receptors. It has recently been licensed in the USA for the treatment of seizures associated with cyclin-dependent kinase-like 5 deficiency disorder. Greater understanding of the causes of DEEs has driven research into the potential use of other novel and repurposed agents. Putative ASMs currently in clinical development for use in DEEs include soticlestat, carisbamate, verapamil, radiprodil, clemizole and lorcaserin.
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Affiliation(s)
- Graeme J. Sills
- School of Life Sciences, University of Glasgow, Room 341, Sir James Black Building, Glasgow G12 8QQ, UK
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Hung TY, Wu SN, Huang CW. Concerted suppressive effects of carisbamate, an anti-epileptic alkyl-carbamate drug, on voltage-gated Na + and hyperpolarization-activated cation currents. Front Cell Neurosci 2023; 17:1159067. [PMID: 37293624 PMCID: PMC10244622 DOI: 10.3389/fncel.2023.1159067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/02/2023] [Indexed: 06/10/2023] Open
Abstract
Carisbamate (CRS, RWJ-333369) is a new anti-seizure medication. It remains unclear whether and how CRS can perturb the magnitude and/or gating kinetics of membrane ionic currents, despite a few reports demonstrating its ability to suppress voltage-gated Na+ currents. In this study, we observed a set of whole-cell current recordings and found that CRS effectively suppressed the voltage-gated Na+ (INa) and hyperpolarization-activated cation currents (Ih) intrinsically in electrically excitable cells (GH3 cells). The effective IC50 values of CRS for the differential suppression of transient (INa(T)) and late INa (INa(L)) were 56.4 and 11.4 μM, respectively. However, CRS strongly decreased the strength (i.e., Δarea) of the nonlinear window component of INa (INa(W)), which was activated by a short ascending ramp voltage (Vramp); the subsequent addition of deltamethrin (DLT, 10 μM) counteracted the ability of CRS (100 μM, continuous exposure) to suppress INa(W). CRS strikingly decreased the decay time constant of INa(T) evoked during pulse train stimulation; however, the addition of telmisartan (10 μM) effectively attenuated the CRS (30 μM, continuous exposure)-mediated decrease in the decay time constant of the current. During continued exposure to deltamethrin (10 μM), known to be a pyrethroid insecticide, the addition of CRS resulted in differential suppression of the amplitudes of INa(T) and INa(L). The amplitude of Ih activated by a 2-s membrane hyperpolarization was diminished by CRS in a concentration-dependent manner, with an IC50 value of 38 μM. For Ih, CRS altered the steady-state I-V relationship and attenuated the strength of voltage-dependent hysteresis (Hys(V)) activated by an inverted isosceles-triangular Vramp. Moreover, the addition of oxaliplatin effectively reversed the CRS-mediated suppression of Hys(V). The predicted docking interaction between CRS and with a model of the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel or between CRS and the hNaV1.7 channel reflects the ability of CRS to bind to amino acid residues in HCN or hNaV1.7 channel via hydrogen bonds and hydrophobic interactions. These findings reveal the propensity of CRS to modify INa(T) and INa(L) differentially and to effectively suppress the magnitude of Ih. INa and Ih are thus potential targets of the actions of CRS in terms of modulating cellular excitability.
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Affiliation(s)
- Te-Yu Hung
- Department of Pediatrics, Chi Mei Medical Center, Tainan, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- College of Medicine, Institute of Basic Medical Sciences, National Cheng Kung University, Tainan, Taiwan
- School of Medicine, College of Medicine, National Sun Yat-sen University, Kaohsiung City, Taiwan
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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Lu C, Zheng J, Cao Y, Bresnahan R, Martin-McGill KJ. Carisbamate add-on therapy for drug-resistant focal epilepsy. Cochrane Database Syst Rev 2021; 12:CD012121. [PMID: 34870321 PMCID: PMC8647098 DOI: 10.1002/14651858.cd012121.pub2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND Epilepsy is one of the most common neurological disorders. Many people with epilepsy are drug-resistant and require add-on therapy, meaning that they concomitantly take multiple antiepileptic drugs. Carisbamate is a drug which is taken orally and inhibits voltage-gated sodium channels. Carisbamate may be useful for drug-resistant focal epilepsy. OBJECTIVES To evaluate the efficacy and tolerability of carisbamate when used as an add-on therapy for drug-resistant focal epilepsy. SEARCH METHODS We searched the following databases on 8 April 2021: Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid) 1946 to April 07, 2021. CRS Web includes randomised or quasi-randomised controlled trials from PubMed, Embase, ClinicalTrials.gov, WHO ICTRP, the Cochrane Central Register of Controlled Trials (CENTRAL), and the specialised registers of Cochrane review groups including Epilepsy. We also searched ongoing trials registers, checked reference lists, and contacted authors of the included trials. SELECTION CRITERIA Double-blind randomised controlled trials (RCTs) comparing carisbamate versus placebo or another antiepileptic drug, as add-on therapy for drug-resistant focal epilepsy. Trials could have a parallel-group or cross-over design. DATA COLLECTION AND ANALYSIS Two review authors independently selected the trials for inclusion, assessed trial quality, and extracted data. The primary outcome was 50% or greater reduction in seizure frequency (responder rate). The secondary outcomes were: seizure freedom, treatment withdrawal (for any reason and due to adverse events); adverse events, and quality of life. We analysed data using the Mantel-Haenszel statistical method and according to the intention-to-treat population. We presented results as risk ratios (RRs) with 95% confidence intervals (CIs). MAIN RESULTS We included four RCTs involving a total of 2211 participants. All four trials compared carisbamate with placebo for drug-resistant focal epilepsy. Participants in all trials were over 16 years of age and received at least one other antiepileptic drug concomitantly. We detected substantial risk of bias across the included trials. All four trials were at high risk of attrition bias due to the incomplete reporting of attrition and the high treatment withdrawal rates noted, especially with higher doses. All four trials also had unclear risk of detection bias, as they did not specify whether outcome assessors were blinded. Meta-analysis suggested that carisbamate produced a higher responder rate compared to placebo (RR 1.36, 95% CI 1.14 to 1.62; 4 studies; moderate-certainty evidence). More participants in the carsibamate group achieved seizure freedom (RR 2.43, 95% CI 0.84 to 7.03; 1 study); withdrew from treatment for any reason (RR 1.32, 95% CI 0.82 to 2.12; 4 studies); and withdrew from treatment due to adverse events (RR 1.80, 95% CI 0.78 to 4.17; 4 studies) than in the placebo group. However, the evidence for the three outcomes was very low-certainty. There was no difference between treatment groups for the proportion of participants experiencing at least one adverse event (RR 1.10, 95% CI 0.93 to 1.30; 2 studies; low-certainty evidence). More participants in the carisbamate group than in the placebo group developed dizziness (RR 2.06, 95% CI 1.23 to 3.44; 4 studies; very low-certainty evidence) and somnolence (RR 1.82, 95% CI 1.28 to 2.58; 4 studies; low-certainty evidence), but not fatigue (RR 1.11, 95% CI 0.73 to 1.68; 3 studies); headache (RR 1.13, 95% CI 0.92 to 1.38; 4 studies); or nausea (RR 1.19, 95% CI 0.81 to 1.75; 3 studies). None of the included trials reported quality of life. AUTHORS' CONCLUSIONS The results suggest that carisbamate may demonstrate efficacy and tolerability as an add-on therapy for drug-resistant focal epilepsy. Importantly, the evidence for all outcomes except responder rate was of low to very low certainty, therefore we are uncertain of the accuracy of the reported effects. The certainty of the evidence is limited by the significant risk of bias associated with the included studies, as well as the statistical heterogeneity detected for some outcomes. Consequently, it is difficult for these findings to inform clinical practice. The studies were all of short duration and only included adult study populations. There is a need for further RCTs with more clear methodology, long-term follow-up, more clinical outcomes, more seizure types, and a broader range of participants.
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Affiliation(s)
- Chuansen Lu
- Department of Neurology, Hainan General Hospital, Hainan Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China
- Department of Neurology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Jinou Zheng
- Department of Neurology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Yue Cao
- Department of Neurology, First Affiliated Hospital, Guangxi Medical University, Nanning, China
| | - Rebecca Bresnahan
- Department of Pharmacology and Therapeutics, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
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Löscher W, Sills GJ, White HS. The ups and downs of alkyl-carbamates in epilepsy therapy: How does cenobamate differ? Epilepsia 2021; 62:596-614. [PMID: 33580520 DOI: 10.1111/epi.16832] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/13/2022]
Abstract
Since 1955, several alkyl-carbamates have been developed for the treatment of anxiety and epilepsy, including meprobamate, flupirtine, felbamate, retigabine, carisbamate, and cenobamate. They have each enjoyed varying levels of success as antiseizure drugs; however, they have all been plagued by the emergence of serious and sometimes life-threatening adverse events. In this review, we compare and contrast their predominant molecular mechanisms of action, their antiseizure profile, and where possible, their clinical efficacy. The preclinical, clinical, and mechanistic profile of the prototypical γ-aminobutyric acidergic (GABAergic) modulator phenobarbital is included for comparison. Like phenobarbital, all of the clinically approved alkyl-carbamates share an ability to enhance inhibitory neurotransmission through modulation of the GABAA receptor, although the specific mechanism of interaction differs among the different drugs discussed. In addition, several alkyl-carbamates have been shown to interact with voltage-gated ion channels. Flupirtine and retigabine share an ability to activate K+ currents mediated by KCNQ (Kv7) K+ channels, and felbamate, carisbamate, and cenobamate have been shown to block Na+ channels. In contrast to other alkyl-carbamates, cenobamate seems to be unique in its ability to preferentially attenuate the persistent rather than transient Na+ current. Results from recent randomized controlled clinical trials with cenobamate suggest that this newest antiseizure alkyl-carbamate possesses a degree of efficacy not witnessed since felbamate was approved in 1993. Given that ceno-bamate's mechanistic profile is unique among the alkyl-carbamates, it is not clear whether this impressive efficacy reflects an as yet undescribed mechanism of action or whether it possesses a unique synergy between its actions at the GABAA receptor and on persistent Na+ currents. The high efficacy of cenobamate is, however, tempered by the risk of serious rash and low tolerability at higher doses, meaning that further safety studies and clinical experience are needed to determine the true clinical value of cenobamate.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany.,Center for Systems Neuroscience Hannover, Hannover, Germany
| | - Graeme J Sills
- School of Life Sciences, University of Glasgow, Glasgow, UK
| | - H Steve White
- Department of Pharmacy, School of Pharmacy, University of Washington, Seattle, Washington, USA
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Selvy M, Cuménal M, Kerckhove N, Courteix C, Busserolles J, Balayssac D. The safety of medications used to treat peripheral neuropathic pain, part 1 (antidepressants and antiepileptics): review of double-blind, placebo-controlled, randomized clinical trials. Expert Opin Drug Saf 2020; 19:707-733. [PMID: 32363948 DOI: 10.1080/14740338.2020.1764934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Peripheral neuropathic pain is a highly disabling condition for patients and a challenge for neurologists and pain physicians. Although many drugs have been assessed in scientific studies, few have demonstrated a clear clinical efficacy against neuropathic pain. Moreover, the paucity of data regarding their safety raised the question on the benefit-risk ratio when used in patients experiencing peripheral neuropathies. AREAS COVERED The authors conducted a review of double-blind, placebo-controlled, randomized clinical trials to assess the safety of medications used to treat neuropathic pain. This first review was focused on antidepressant and antiepileptic medications. The aim was to provide an overview of the treatment-emergent adverse events (≥10%) and the serious adverse effects described in clinical trials. EXPERT OPINION Among antiepileptics and antidepressants, duloxetine appeared to have the most detailed safety for the treatment of peripheral neuropathic pain. Over all studies, the most commonly reported adverse effects were dizziness, drowsiness, nausea, and constipation. Only 20.0% of the included studies (N = 90) presented a good description of adverse effects that included a statistical comparison vers usa placebo group. Important methodological improvements must be made to improve the assessment of medication safety in future clinical trials.
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Affiliation(s)
- Marie Selvy
- Université Clermont Auvergne, CHU Clermont-Ferrand, Service de chirurgie digestive, INSERM, NEURO-DOL , Clermont-Ferrand, France
| | - Mélissa Cuménal
- Université Clermont Auvergne, INSERM NEURO-DOL , Clermont-Ferrand, France
| | - Nicolas Kerckhove
- Université Clermont Auvergne, CHU Clermont-Ferrand, Service de pharmacologie médicale, INSERMNEURO-DOL, Institut Analgesia , Clermont-Ferrand, France
| | - Christine Courteix
- Université Clermont Auvergne, INSERM NEURO-DOL , Clermont-Ferrand, France
| | - Jérôme Busserolles
- Université Clermont Auvergne, INSERM NEURO-DOL , Clermont-Ferrand, France
| | - David Balayssac
- Université Clermont Auvergne, CHU Clermont-Ferrand, Délégation à la recherche clinique et à l'innovation, INSERM, NEURO-DOL , Clermont-Ferrand, France
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Neurochemical Changes and c-Fos Mapping in the Brain after Carisbamate Treatment of Rats Subjected to Lithium-Pilocarpine-Induced Status Epilepticus. Pharmaceuticals (Basel) 2017; 10:ph10040085. [PMID: 29104261 PMCID: PMC5748642 DOI: 10.3390/ph10040085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/20/2017] [Accepted: 10/27/2017] [Indexed: 12/03/2022] Open
Abstract
The administration of lithium–pilocarpine (LiPilo) in adult rats is a validated model reproducing the main clinical and neuropathological features of temporal lobe epilepsy (TLE). Previous studies have shown that carisbamate (CRS) has the property of modifying epileptogenesis in this model. When treated with CRS, about 50% of rats undergoing LiPilo status epilepticus (SE) develop non-convulsive seizures (NCS) instead of convulsive ones (commonly observed in TLE). The goal of this work was to determine some of the early changes that occur after CRS administration, as they could be involved in the insult- and epileptogenesis-modifying effects of CRS. Thus, we performed high-performance liquid chromatography (HPLC) to quantify levels of amino acids and monoamines, and c-Fos immunohistochemical labeling to map cerebral activation during seizures. Comparing rats treated one hour after SE onset with saline (CT), CRS, or diazepam (DZP), HPLC showed that 4 h after SE onset, dopamine (DA), norepinephrine (NE), and GABA levels were normal, whereas serotonin levels were increased. Using c-Fos labeling, we demonstrated increased activity in thalamic mediodorsal (MD) and laterodorsal (LD) nuclei in rats treated with CRS. In summary, at early times, CRS seems to modulate excitability by acting on some monoamine levels and increasing activity of MD and LD thalamic nuclei, suggesting a possible involvement of these nuclei in insult- and/or epileptogenesis-modifying effects of CRS.
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Marques-Carneiro JE, Persike DS, Litzahn JJ, Cassel JC, Nehlig A, Fernandes MJDS. Hippocampal Proteome of Rats Subjected to the Li-Pilocarpine Epilepsy Model and the Effect of Carisbamate Treatment. Pharmaceuticals (Basel) 2017; 10:ph10030067. [PMID: 28758946 PMCID: PMC5620611 DOI: 10.3390/ph10030067] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 12/17/2022] Open
Abstract
In adult rats, the administration of lithium–pilocarpine (LiPilo) reproduces most clinical and neuropathological features of human temporal lobe epilepsy (TLE). Carisbamate (CRS) possesses the property of modifying epileptogenesis in this model. Indeed, about 50% of rats subjected to LiPilo status epilepticus (SE) develop non-convulsive seizures (NCS) instead of motor seizures when treated with CRS. However, the mechanisms underlying these effects remain unknown. The aim of this study was to perform a proteomic analysis in the hippocampus of rats receiving LiPilo and developing motor seizures or NCS following CRS treatment. Fifteen adult male Sprague–Dawley rats were used. SE was induced by LiPilo injection. CRS treatment was initiated at 1 h and 9 h after SE onset and maintained for 7 days, twice daily. Four groups were studied after video-EEG control of the occurrence of motor seizures: a control group receiving saline (CT n = 3) and three groups that underwent SE: rats treated with diazepam (DZP n = 4), rats treated with CRS displaying NCS (CRS-NCS n = 4) or motor seizures (CRS-TLE n = 4). Proteomic analysis was conducted by 2D-SDS-PAGE. Twenty-four proteins were found altered. In the CRS-NCS group, proteins related to glycolysis and ATP synthesis were down-regulated while proteins associated with pyruvate catabolism were up-regulated. Moreover, among the other proteins differentially expressed, we found proteins related to inflammatory processes, protein folding, tissue regeneration, response to oxidative stress, gene expression, biogenesis of synaptic vesicles, signal transduction, axonal transport, microtubule formation, cell survival, and neuronal plasticity. Our results suggest a global reduction of glycolysis and cellular energy production that might affect brain excitability. In addition, CRS seems to modulate proteins related to many other pathways that could significantly participate in the epileptogenesis-modifying effect observed.
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Affiliation(s)
- José Eduardo Marques-Carneiro
- Departamento de Neurologia e Neurocirurgia, Disciplina Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP 04039-032 São Paulo, Brazil.
- Unistra, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, Université de Strasbourg, 67000 Strasbourg, France.
- CNRS, UMR 7364, LNCA, 12 rue Goethe, 67000 Strasbourg, France.
| | - Daniele Suzete Persike
- Departamento de Neurologia e Neurocirurgia, Disciplina Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP 04039-032 São Paulo, Brazil.
| | - Julia Julie Litzahn
- Departamento de Neurologia e Neurocirurgia, Disciplina Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP 04039-032 São Paulo, Brazil.
| | - Jean-Christophe Cassel
- Unistra, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Faculté de Psychologie, Université de Strasbourg, 67000 Strasbourg, France.
- CNRS, UMR 7364, LNCA, 12 rue Goethe, 67000 Strasbourg, France.
| | - Astrid Nehlig
- INSERM U 1129 "Infantile Epilepsies and Brain Plasticity", 75015 Paris, France.
- Université Paris Descartes, Sorbonne Paris Cité, CEA, 91990 Gif sur Yvette, France.
| | - Maria José da Silva Fernandes
- Departamento de Neurologia e Neurocirurgia, Disciplina Neurociência, Escola Paulista de Medicina, Universidade Federal de São Paulo, SP 04039-032 São Paulo, Brazil.
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Kim DY, Zhang FX, Nakanishi ST, Mettler T, Cho IH, Ahn Y, Hiess F, Chen L, Sullivan PG, Chen SRW, Zamponi GW, Rho JM. Carisbamate blockade of T-type voltage-gated calcium channels. Epilepsia 2017; 58:617-626. [PMID: 28230232 DOI: 10.1111/epi.13710] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2017] [Indexed: 01/23/2023]
Abstract
OBJECTIVES Carisbamate (CRS) is a novel monocarbamate compound that possesses antiseizure and neuroprotective properties. However, the mechanisms underlying these actions remain unclear. Here, we tested both direct and indirect effects of CRS on several cellular systems that regulate intracellular calcium concentration [Ca2+ ]i . METHODS We used a combination of cellular electrophysiologic techniques, as well as cell viability, Store Overload-Induced Calcium Release (SOICR), and mitochondrial functional assays to determine whether CRS might affect [Ca2+ ]i levels through actions on the endoplasmic reticulum (ER), mitochondria, and/or T-type voltage-gated Ca2+ channels. RESULTS In CA3 pyramidal neurons, kainic acid induced significant elevations in [Ca2+ ]i and long-lasting neuronal hyperexcitability, both of which were reversed in a dose-dependent manner by CRS. Similarly, CRS suppressed spontaneous rhythmic epileptiform activity in hippocampal slices exposed to zero-Mg2+ or 4-aminopyridine. Treatment with CRS also protected murine hippocampal HT-22 cells against excitotoxic injury with glutamate, and this was accompanied by a reduction in [Ca2+ ]i . Neither kainic acid nor CRS alone altered the mitochondrial membrane potential (ΔΨ) in intact, acutely isolated mitochondria. In addition, CRS did not affect mitochondrial respiratory chain activity, Ca2+ -induced mitochondrial permeability transition, and Ca2+ release from the ER. However, CRS significantly decreased Ca2+ flux in human embryonic kidney tsA-201 cells transfected with Cav 3.1 (voltage-dependent T-type Ca2+ ) channels. SIGNIFICANCE Our data indicate that the neuroprotective and antiseizure activity of CRS likely results in part from decreased [Ca2+ ]i accumulation through blockade of T-type Ca2+ channels.
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Affiliation(s)
- Do Young Kim
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital & Medical Center, Phoenix, Arizona, U.S.A
| | - Fang-Xiong Zhang
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Stan T Nakanishi
- Department of Biology, University of Hawaii at Hilo, Hilo, Hawaii, U.S.A
| | - Timothy Mettler
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital & Medical Center, Phoenix, Arizona, U.S.A
| | - Ik-Hyun Cho
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital & Medical Center, Phoenix, Arizona, U.S.A
| | - Younghee Ahn
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Florian Hiess
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Lina Chen
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Patrick G Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, U.S.A
| | - S R Wayne Chen
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jong M Rho
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
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Affiliation(s)
- Chuansen Lu
- First Affiliated Hospital, Guangxi Medical University; Department of Neurology; 6 Shuangyong road Nanning P.R. China China 530021
| | - Jinou Zheng
- First Affiliated Hospital, Guangxi Medical University; Department of Neurology; 6 Shuangyong road Nanning P.R. China China 530021
| | - Yue Cao
- First Affiliated Hospital, Guangxi Medical University; Department of Neurology; 6 Shuangyong road Nanning P.R. China China 530021
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Król M, Ufnal M, Szulczyk B, Podsadni P, Drapała A, Turło J, Dawidowski M. Characterization of Disopyramide derivative ADD424042 as a non-cardiotoxic neuronal sodium channel blocker with broad-spectrum anticonvulsant activity in rodent seizure models. Eur J Pharm Sci 2016; 81:42-51. [DOI: 10.1016/j.ejps.2015.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 09/28/2015] [Accepted: 10/02/2015] [Indexed: 12/13/2022]
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12
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Hadera MG, Faure JB, Berggaard N, Tefera TW, Nehlig A, Sonnewald U. The anticonvulsant actions of carisbamate associate with alterations in astrocyte glutamine metabolism in the lithium-pilocarpine epilepsy model. J Neurochem 2014; 132:532-545. [PMID: 25345404 DOI: 10.1111/jnc.12977] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 09/30/2014] [Accepted: 10/13/2014] [Indexed: 01/18/2023]
Abstract
As reported previously, in the lithium-pilocarpine model of temporal lobe epilepsy (TLE), carisbamate (CRS) produces strong neuroprotection, leads to milder absence-like seizures, and prevents behavioral impairments in a subpopulation of rats. To understand the metabolic basis of these effects, here we injected 90 mg/kg CRS or vehicle twice daily for 7 days starting 1 h after status epilepticus (SE) induction in rats. Two months later, we injected [1-13 C]glucose and [1,2-13 C]acetate followed by head microwave fixation after 15 min. 13 C incorporation into metabolites was analyzed using 13 C magnetic resonance spectroscopy. We found that SE reduced neuronal mitochondrial metabolism in the absence but not in the presence of CRS. Reduction in glutamate level was prevented by CRS and aspartate levels were similar to controls only in rats displaying absence-like seizures after treatment [CRS-absence-like epilepsy (ALE)]. Glutamine levels in CRS-ALE rats were higher compared to controls in hippocampal formation and limbic structures while unchanged in rats displaying motor spontaneous recurrent seizures after treatment (CRS-TLE). Astrocytic mitochondrial metabolism was reduced in CRS-TLE, and either enhanced or unaffected in CRS-ALE rats, which did not affect the transfer of glutamine from astrocytes to neurons. In conclusion, CRS prevents reduction in neuronal mitochondrial metabolism but its effect on astrocytes is likely key in determining outcome of treatment in this model. To understand the metabolic basis of the strong neuroprotection and reduction in seizure severity caused by carisbamate (CRS) in the lithium-pilocarpine (Li-Pilo) model of temporal lobe epilepsy (TLE), we injected CRS for 7 days starting 1 h after status epilepticus and 2 months later [1-13 C]glucose and [1,2-13 C]acetate. 13 C Magnetic resonance spectroscopy analysis was performed on brain extracts and we found that CRS prevented reduction in neuronal mitochondrial metabolism but its effect on astrocytes was likely key in determining outcome of treatment in this model. ALE = absence like epilepsy; acetyl CoA = acetyl coenzyme A; GS = glutamine synthetase; PAG = phosphate activated glutaminase; PC = pyruvate carboxylase; OAA = oxaloacetate; TCA cycle = tricarboxylic acid cycle.
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Affiliation(s)
- Mussie Ghezu Hadera
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jean-Baptiste Faure
- Faculty of Medicine, INSERM U 666, University of Strasbourg, Strasbourg, France.,Laboratory of Cognitive and Adaptive Neuroscience (LNCA), Faculty of Psychology, UMR 7364, University of Strasbourg-CNRS, Strasbourg, France
| | - Nina Berggaard
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Tesfaye Wolde Tefera
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Astrid Nehlig
- Faculty of Medicine, INSERM U 666, University of Strasbourg, Strasbourg, France
| | - Ursula Sonnewald
- Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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Faure JB, Marques-Carneiro JE, Akimana G, Cosquer B, Ferrandon A, Herbeaux K, Koning E, Barbelivien A, Nehlig A, Cassel JC. Attention and executive functions in a rat model of chronic epilepsy. Epilepsia 2014; 55:644-653. [PMID: 24621352 DOI: 10.1111/epi.12549] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Temporal lobe epilepsy is a relatively frequent, invalidating, and often refractory neurologic disorder. It is associated with cognitive impairments that affect memory and executive functions. In the rat lithium-pilocarpine temporal lobe epilepsy model, memory impairment and anxiety disorder are classically reported. Here we evaluated sustained visual attention in this model of epilepsy, a function not frequently explored. METHODS Thirty-five Sprague-Dawley rats were subjected to lithium-pilocarpine status epilepticus. Twenty of them received a carisbamate treatment for 7 days, starting 1 h after status epilepticus onset. Twelve controls received lithium and saline. Five months later, attention was assessed in the five-choice serial reaction time task, a task that tests visual attention and inhibitory control (impulsivity/compulsivity). Neuronal counting was performed in brain regions of interest to the functions studied (hippocampus, prefrontal cortex, nucleus basalis magnocellularis, and pedunculopontine tegmental nucleus). RESULTS Lithium-pilocarpine rats developed motor seizures. When they were able to learn the task, they exhibited attention impairment and a tendency toward impulsivity and compulsivity. These disturbances occurred in the absence of neuronal loss in structures classically related to attentional performance, although they seemed to better correlate with neuronal loss in hippocampus. Globally, rats that received carisbamate and developed motor seizures were as impaired as untreated rats, whereas those that did not develop overt motor seizures performed like controls, despite evidence for hippocampal damage. SIGNIFICANCE This study shows that attention deficits reported by patients with temporal lobe epilepsy can be observed in the lithium-pilocarpine model. Carisbamate prevents the occurrence of motor seizures, attention impairment, impulsivity, and compulsivity in a subpopulation of neuroprotected rats.
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Affiliation(s)
- Jean-Baptiste Faure
- Laboratory of Cognitive and Adaptive Neuroscience (LNCA), Faculty of Psychology, UMR 7364 University of Strasbourg - CNRS, Strasbourg, France; Faculty of Medicine, INSERM U 666, Strasbourg, France
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14
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Waszkielewicz AM, Gunia A, Szkaradek N, Słoczyńska K, Krupińska S, Marona H. Ion channels as drug targets in central nervous system disorders. Curr Med Chem 2013; 20:1241-85. [PMID: 23409712 PMCID: PMC3706965 DOI: 10.2174/0929867311320100005] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 01/14/2013] [Accepted: 01/18/2013] [Indexed: 12/27/2022]
Abstract
Ion channel targeted drugs have always been related with either the central nervous system (CNS), the peripheral nervous system, or the cardiovascular system. Within the CNS, basic indications of drugs are: sleep disorders, anxiety, epilepsy, pain, etc. However, traditional channel blockers have multiple adverse events, mainly due to low specificity of mechanism of action. Lately, novel ion channel subtypes have been discovered, which gives premises to drug discovery process led towards specific channel subtypes. An example is Na(+) channels, whose subtypes 1.3 and 1.7-1.9 are responsible for pain, and 1.1 and 1.2 - for epilepsy. Moreover, new drug candidates have been recognized. This review is focusing on ion channels subtypes, which play a significant role in current drug discovery and development process. The knowledge on channel subtypes has developed rapidly, giving new nomenclatures of ion channels. For example, Ca(2+)s channels are not any more divided to T, L, N, P/Q, and R, but they are described as Ca(v)1.1-Ca(v)3.3, with even newer nomenclature α1A-α1I and α1S. Moreover, new channels such as P2X1-P2X7, as well as TRPA1-TRPV1 have been discovered, giving premises for new types of analgesic drugs.
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Affiliation(s)
- A M Waszkielewicz
- Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland.
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15
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Shim S, El Mansari M, Blier P. Modulation of the Antidepressant-Like Effects of Sustained Administration of Carisbamate and Lamotrigine on Monoaminergic Systems: Electrophysiological Studies in the Rat Brain. J Pharmacol Exp Ther 2013; 347:487-96. [DOI: 10.1124/jpet.113.203315] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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16
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Faure JB, Akimana G, Carneiro JEM, Cosquer B, Ferrandon A, Geiger K, Koning E, Penazzi L, Cassel JC, Nehlig A. A comprehensive behavioral evaluation in the lithium-pilocarpine model in rats: Effects of carisbamate administration during status epilepticus. Epilepsia 2013; 54:1203-13. [DOI: 10.1111/epi.12219] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Jean-Baptiste Faure
- Faculty of Medicine; INSERM U 666; Strasbourg France
- Laboratory of Cognitive and Adaptive Neuroscience; CNRS-UDS UMR 7364; Strasbourg France
| | - Gladys Akimana
- Faculty of Medicine; INSERM U 666; Strasbourg France
- Laboratory of Cognitive and Adaptive Neuroscience; CNRS-UDS UMR 7364; Strasbourg France
| | - José E. M. Carneiro
- Faculty of Medicine; INSERM U 666; Strasbourg France
- Laboratory of Cognitive and Adaptive Neuroscience; CNRS-UDS UMR 7364; Strasbourg France
| | - Brigitte Cosquer
- Laboratory of Cognitive and Adaptive Neuroscience; CNRS-UDS UMR 7364; Strasbourg France
| | | | - Karin Geiger
- Laboratory of Cognitive and Adaptive Neuroscience; CNRS-UDS UMR 7364; Strasbourg France
| | | | - Lorène Penazzi
- Laboratory of Cognitive and Adaptive Neuroscience; CNRS-UDS UMR 7364; Strasbourg France
| | | | - Astrid Nehlig
- Faculty of Medicine; INSERM U 666; Strasbourg France
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17
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Moore K, Zannikos P, Solanki B, Greenspan A, Verhaeghe T, Brashear HR. Effect of Mild and Moderate Hepatic Impairment on the Pharmacokinetics and Safety of Carisbamate. J Clin Pharmacol 2013; 52:738-46. [DOI: 10.1177/0091270011403313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Guo F, Xu X, Cai J, Hu H, Sun W, He G, Shao D, Wang L, Chen T, Shaw C, Zhu T, Hao L. The up-regulation of voltage-gated sodium channels subtypes coincides with an increased sodium current in hippocampal neuronal culture model. Neurochem Int 2013; 62:287-95. [DOI: 10.1016/j.neuint.2013.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/06/2012] [Accepted: 01/06/2013] [Indexed: 01/24/2023]
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Cognitive effects of carisbamate in randomized, placebo-controlled, healthy-volunteer, multidose studies. Epilepsy Behav 2011; 22:324-30. [PMID: 21849260 DOI: 10.1016/j.yebeh.2011.07.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 07/07/2011] [Accepted: 07/08/2011] [Indexed: 11/24/2022]
Abstract
Adverse cognitive effects are an important concern for drugs that influence the central nervous system. Carisbamate is a novel drug in development for treatment of seizures and neuropathic pain. Information on its cognitive effects is limited. Three controlled, multiple-dose, crossover studies with treatment durations of 5-9 days were designed to examine the cognitive effects of carisbamate on healthy volunteers. In one study, apparent dose-dependent effects on response, vigilance, and recognition speed were observed (1000 mg and 1500 mg/day). Carisbamate did not differ from placebo for most variables in the other two studies, but increased reaction time and reduced Sternberg memory were seen at higher dosages. Carisbamate did not produce clinically significant adverse effects on cognitive performance at doses <1000 mg/day. Effects were mild to modest at the higher doses tested.
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20
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Lee CY, Lee ML, Shih CC, Liou HH. Carisbamate (RWJ-333369) inhibits glutamate transmission in the granule cell of the dentate gyrus. Neuropharmacology 2011; 61:1239-47. [PMID: 21824485 DOI: 10.1016/j.neuropharm.2011.07.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 07/08/2011] [Accepted: 07/09/2011] [Indexed: 11/26/2022]
Abstract
Carisbamate (CRS, RWJ-333369) is a novel antiepileptic drug awaiting approval for use in the treatment of partial and generalized seizures. Our aim was to determine whether CRS modulates synaptic transmission in the dentate gyrus (DG) and the underlying mechanism. The whole-cell patch-clamp method was used to record AMPA receptor- and NMDA receptor-mediated excitatory postsynaptic currents (EPSC(AMPA) and EPSC(NMDA)) and GABA(A) receptor-mediated inhibitory postsynaptic currents (IPSCs) in granule cells of the DG in brain slices prepared from 3- to 5-week-old male Wistar rats. CRS (30-300 μM) inhibited the evoked EPSC(AMPA) and EPSC(NMDA) by the same extent (20%) with significantly altered CV(-2), suggesting presynaptic modulation. It did not significantly change the inward currents induced by AMPA application. The inhibitory effect of CRS on the evoked EPSC(AMPA) was not occluded by selective voltage-gated Ca(2+) channel blockers, ruling out the involvement of presynaptic Ca(2+) channels. The frequency, but not the amplitude, of spontaneous EPSC(AMPA) was significantly reduced by CRS. However, CRS did not alter either the frequency or the amplitude of TTX-insensitive miniature EPSC(AMPA), indicating an action potential-dependent mechanism was involved. In addition, CRS (100 or 300 μM) did not significantly change the amplitude of the evoked IPSCs. To summarize, our results suggest that CRS reduces glutamatergic transmission by an action potential-dependent presynaptic mechanism and consequently inhibits excitatory synaptic strength in the DG without affecting GABAergic transmission. This effect may contribute to the antiepileptic action observed clinically at therapeutic concentrations of CRS.
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Affiliation(s)
- Chun-Yao Lee
- Department of Pharmacology, College of Medicine, National Taiwan University, Taiwan
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21
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Ono T, Moshé SL, Galanopoulou AS. Carisbamate acutely suppresses spasms in a rat model of symptomatic infantile spasms. Epilepsia 2011; 52:1678-84. [PMID: 21770922 DOI: 10.1111/j.1528-1167.2011.03173.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE Infantile spasms are the signature seizures of West syndrome. The conventional treatments for infantile spasms, such as adrenocorticotropic hormone (ACTH) and vigabatrin, are not always effective, especially in symptomatic infantile spasms (SIS). We tested the efficacy of carisbamate, a novel neurotherapeutic drug, to suppress spasms in the multiple-hit rat model of SIS, and compared it with phenytoin to determine if its effect is via sodium-channel blockade. METHODS Sprague-Dawley rats received right intracerebral infusions of doxorubicin and lipopolysaccharide at postnatal day 3 (PN3) and intraperitoneal p-chlorophenylalanine at PN5. A single intraperitoneal injection of carisbamate was administered at PN4, after the onset of spasms, at the following doses: 10 mg/kg (CRS-10), 30 mg/kg (CRS-30), and 60 mg/kg (CRS-60), and was compared to vehicle-injected group (VEH). Video-monitoring of PN6-7 CRS-60 or VEH-injected pups was also done. KEY FINDINGS Carisbamate acutely reduced both behavioral spasms (CRS-30 and CRS-60 groups only) and electroclinical spasms during the first 2-3 postinjection hours, without detectable toxicity or mortality. In contrast, phenytoin (20 or 50 mg/kg) failed to suppress spasms. SIGNIFICANCE Our findings provide preclinical evidence that carisbamate displays acute anticonvulsive effect on spasms through a sodium channel-independent mechanism. Because spasms in the multiple-hit rat model are refractory to ACTH and transiently sensitive to vigabatrin, carisbamate may constitute a candidate new therapy for SIS, including the ACTH-refractory spasms. Further confirmation with clinical studies is needed.
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Affiliation(s)
- Tomonori Ono
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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22
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Liu Y, Beck EJ, Flores CM. Validation of a patch clamp screening protocol that simultaneously measures compound activity in multiple states of the voltage-gated sodium channel Nav1.2. Assay Drug Dev Technol 2011; 9:628-34. [PMID: 21675872 DOI: 10.1089/adt.2011.0375] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Hyperactivity of voltage-gated sodium channels underlies, at least in part, a range of pathological states, including pain and epilepsy. Selective blockers of these channels may offer effective treatment of such disorders. Currently employed methods to screen for sodium channel blockers, however, are inadequate to rationally identify mechanistically diverse blockers, limiting the potential range of indications that may be treated by such agents. Here, we describe an improved patch clamp screening assay that increases the mechanistic diversity of sodium channel blockers being identified. Using QPatch HT, a medium-throughput, automated patch clamp system, we tested three common sodium channel blockers (phenytoin, lidocaine, and tetrodotoxin) with distinct mechanistic profiles at Nav1.2. The single-voltage protocol employed in this assay simultaneously measured the compound activity in multiple states, including the slow inactivated state, of the channel. A long compound incubation period (10 s) was introduced during channel inactivation to increase the probability of identifying "slow binders." As such, phenytoin, which preferentially binds with slow kinetics to the fast inactivated state, exhibited significantly higher potency than that obtained from a brief exposure (100 ms) used in typical assays. This assay also successfully detected the use-dependent block of tetrodotoxin, a well-documented property of this molecule yet unobserved in typical patch clamp protocols. These results indicate that the assay described here can increase the likelihood of identification and mechanistic diversity of sodium channel blockers from a primary screen. It can also be used to efficiently guide the in vitro optimization of leads that retain the desired mechanistic properties.
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Affiliation(s)
- Yi Liu
- Drug Discovery, Johnson & Johnson Pharmaceutical Research and Development, Spring House, Pennsylvania, USA.
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23
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François J, Germe K, Ferrandon A, Koning E, Nehlig A. Carisbamate has powerful disease-modifying effects in the lithium-pilocarpine model of temporal lobe epilepsy. Neuropharmacology 2011; 61:313-28. [PMID: 21539848 DOI: 10.1016/j.neuropharm.2011.04.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Revised: 04/13/2011] [Accepted: 04/15/2011] [Indexed: 11/30/2022]
Abstract
Lithium-pilocarpine, a relevant model of temporal lobe epilepsy was used to test the neuroprotective and antiepileptogenic effects of carisbamate. Status epilepticus (SE) was induced in adult rats by lithium and pilocarpine. Carisbamate (30, 60, 90, and 120 mg/kg) was injected at 1 and 9 h after SE onset and continued twice daily for 6 additional days. The reference groups received diazepam instead of carisbamate. Neuroprotection was assessed during the first 24 h of SE with Fluoro-Jade B and after 14 days with thionine staining. SE severity and epileptic outcome were assessed by video, and surface and depth electroencephalographic recordings. At the two highest doses, carisbamate treatment reduced SE severity; produced strong neuroprotection of hippocampus, ventral cortices, thalamus, and amygdala; prevented mossy fiber sprouting in the dentate gyrus of the hippocampus; and delayed or suppressed the occurrence of spontaneous motor seizures. Rats with no spontaneous motor seizures displayed spike-and-wave discharges that share all the characteristics of absence seizures. In conclusion, carisbamate is able to induce strong neuroprotection and affect the nature of epileptogenic events occurring during and after lithium-pilocarpine status epilepticus, reflecting marked insult- and disease-modifying effects.
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Affiliation(s)
- Jennifer François
- InsermU666, University Louis Pasteur; Faculty of Medicine, 11 rue Humann, 67085 Strasbourg Cedex, France.
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McCusker EC, D'Avanzo N, Nichols CG, Wallace BA. Simplified bacterial "pore" channel provides insight into the assembly, stability, and structure of sodium channels. J Biol Chem 2011; 286:16386-91. [PMID: 21454659 PMCID: PMC3091244 DOI: 10.1074/jbc.c111.228122] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Eukaryotic sodium channels are important membrane proteins involved in ion
permeation, homeostasis, and electrical signaling. They are long, multidomain
proteins that do not express well in heterologous systems, and hence,
structure/function and biochemical studies on purified sodium channel proteins
have been limited. Bacteria produce smaller, homologous tetrameric single domain
channels specific for the conductance of sodium ions. They consist of N-terminal
voltage sensor and C-terminal pore subdomains. We designed a functional
pore-only channel consisting of the final two transmembrane helices, the
intervening P-region, and the C-terminal extramembranous region of the sodium
channel from the marine bacterium Silicibacter pomeroyi. This
sodium “pore” channel forms a tetrameric, folded structure that is
capable of supporting sodium flux in phospholipid vesicles. The pore-only
channel is more thermally stable than its full-length counterpart, suggesting
that the voltage sensor subdomain may destabilize the full-length channel. The
pore subdomains can assemble, fold, and function independently from the voltage
sensor and exhibit similar ligand-blocking characteristics as the intact
channel. The availability of this simple pore-only construct should enable
high-level expression for the testing of potential new ligands and enhance our
understanding of the structural features that govern sodium selectivity and
permeability.
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Affiliation(s)
- Emily C McCusker
- Department of Crystallography, Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, United Kingdom
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Therisa KK, Desai PV. Study of epileptiform activity in cerebral ganglion of mud crab Scylla serrata. INVERTEBRATE NEUROSCIENCE 2011; 11:21-7. [PMID: 21249512 DOI: 10.1007/s10158-011-0114-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 01/05/2011] [Indexed: 10/18/2022]
Abstract
An attempt is made to induce in mud crab (Scylla serrata) epileptiform activities that resemble the generalized epileptic seizures. Cerebral ganglion of crab was exposed in situ, to a convulsant drug pentylenetetrazole (PTZ) 100 mM, for induction of seizures. Also, crabs were pretreated with antiepileptic drug viz sodium valproate (120 μmol/l) to inhibit epileptiform activities. The surface electrical discharges of cerebral ganglion were recorded using Unkelscope (MIT, USA) in control as well as experimental animals. The cerebral ganglion of crab showed a pattern of high cerebral electrical discharges after PTZ treatment compared to control. The sodium valproate promoted sedative action in control and prevented PTZ-mediated epileptiform discharges. Glutamate and GABA contents in cerebral ganglion were assayed. Glutamate level increased (31.45%) during PTZ treatment with concomitant decrease (43.93%) in GABA. Sodium valproate had no effect on glutamate concentration, but it decreased GABA by 24.75%. The present study shows that epileptiform activities can be induced in crabs.
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Affiliation(s)
- K K Therisa
- Department of Zoology, Goa University, Taleigao Plateau, India
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Progress report on new antiepileptic drugs: A summary of the Tenth Eilat Conference (EILAT X). Epilepsy Res 2010; 92:89-124. [DOI: 10.1016/j.eplepsyres.2010.09.001] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 08/25/2010] [Accepted: 09/12/2010] [Indexed: 01/09/2023]
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Löscher W, Brandt C. Prevention or modification of epileptogenesis after brain insults: experimental approaches and translational research. Pharmacol Rev 2010; 62:668-700. [PMID: 21079040 PMCID: PMC3014230 DOI: 10.1124/pr.110.003046] [Citation(s) in RCA: 288] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Diverse brain insults, including traumatic brain injury, stroke, infections, tumors, neurodegenerative diseases, and prolonged acute symptomatic seizures, such as complex febrile seizures or status epilepticus (SE), can induce "epileptogenesis," a process by which normal brain tissue is transformed into tissue capable of generating spontaneous recurrent seizures. Furthermore, epileptogenesis operates in cryptogenic causes of epilepsy. In view of the accumulating information about cellular and molecular mechanisms of epileptogenesis, it should be possible to intervene in this process before the onset of seizures and thereby either prevent the development of epilepsy in patients at risk or increase the potential for better long-term outcome, which constitutes a major clinical need. For identifying pharmacological interventions that prevent, interrupt or reverse the epileptogenic process in people at risk, two groups of animal models, kindling and SE-induced recurrent seizures, have been recommended as potentially useful tools. Furthermore, genetic rodent models of epileptogenesis are increasingly used in assessing antiepileptogenic treatments. Two approaches have been used in these different model categories: screening of clinically established antiepileptic drugs (AEDs) for antiepileptogenic or disease-modifying potential, and targeting the key causal mechanisms that underlie epileptogenesis. The first approach indicated that among various AEDs, topiramate, levetiracetam, carisbamate, and valproate may be the most promising. On the basis of these experimental findings, two ongoing clinical trials will address the antiepileptogenic potential of topiramate and levetiracetam in patients with traumatic brain injury, hopefully translating laboratory discoveries into successful therapies. The second approach has highlighted neurodegeneration, inflammation and up-regulation of immune responses, and neuronal hyperexcitability as potential targets for antiepileptogenesis or disease modification. This article reviews these areas of progress and discusses the challenges associated with discovery of antiepileptogenic therapies.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology and Pharmacy, University of Veterinary Medicine, Bünteweg 17, Hannover, Germany.
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Elble RJ, Biondi DM, Ascher S, Wiegand F, Hulihan J. Carisbamate in essential tremor: Brief report of a proof of concept study. Mov Disord 2010; 25:634-8. [DOI: 10.1002/mds.22872] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Sperling MR, Greenspan A, Cramer JA, Kwan P, Kälviäinen R, Halford JJ, Schmitt J, Yuen E, Cook T, Haas M, Novak G. Carisbamate as adjunctive treatment of partial onset seizures in adults in two randomized, placebo-controlled trials. Epilepsia 2010; 51:333-43. [DOI: 10.1111/j.1528-1167.2009.02318.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bialer M, White HS. Key factors in the discovery and development of new antiepileptic drugs. Nat Rev Drug Discov 2010; 9:68-82. [PMID: 20043029 DOI: 10.1038/nrd2997] [Citation(s) in RCA: 374] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Since the early 1990s, many new antiepileptic drugs (AEDs) that offer appreciable advantages in terms of their favourable pharmacokinetics, improved tolerability and lower potential for drug-drug interactions have entered the market. However, despite the therapeutic arsenal of old and new AEDs, approximately 30% of patients with epilepsy still suffer from seizures. Thus, there remains a substantial need for the development of more efficacious AEDs for patients with refractory seizures. Here, we briefly review the emerging knowledge on the pathological basis of epilepsy and how it might best be used in the design of new therapeutics. We also discuss the current approach to AED discovery and highlight some of the unique features of newer models of pharmacoresistance and epileptogenesis that have emerged in recent years.
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Affiliation(s)
- Meir Bialer
- Institute of Drug Research, School of Pharmacy, Faculty of Medicine, and the David R. Bloom Centre for Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel.
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