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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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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: 33] [Impact Index Per Article: 11.0] [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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9
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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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Chou MY, Lee CY, Liou HH, Pan CY. Phenytoin attenuates the hyper-exciting neurotransmission in cultured embryonic cortical neurons. Neuropharmacology 2014; 83:54-61. [PMID: 24721626 DOI: 10.1016/j.neuropharm.2014.03.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 03/17/2014] [Accepted: 03/22/2014] [Indexed: 11/26/2022]
Abstract
Phenytoin is an effective anti-epileptic drug that inhibits Na(+) channel activities; however, how phenytoin modulates synaptic transmission to soothe epileptic symptoms is not clear. To characterize the effects of phenytoin regulation on neurotransmission, we studied the electrophysical properties of cultured embryonic cortical neurons. Phenytoin inhibited the inward Na(+) current in a dose-dependent manner with an IC50 of 16.8 μM, and at 100 μM, the inhibitory effect of phenytoin on the Na(+) current was proportional to the frequency applied. In cultured neurons, phenytoin significantly decreased the action potential firing rate and the peak potential. To study the effect of phenytoin in neurotransmission, we measured the Ca(2+) responses from stimulated target neurons and their neighboring neurons. Phenytoin significantly suppressed the Ca(2+) responses evoked by strong stimulations in the target and neighboring neurons, and exerted a decreased inhibitory effect under moderate stimulation. Picrotoxin, a GABAA receptor antagonist, enhanced the recorded spontaneous excitatory postsynaptic current activities. After picrotoxin-induced enhancement, phenytoin had a more pronounced effect on the suppression of the spontaneous hyper-exciting excitatory postsynaptic current (>100 pA), but it only mildly inhibited the general excitatory postsynaptic current. Our results demonstrate that phenytoin suppresses the efficacy of neurotransmission especially for the high-frequency stimulation by reducing the Na(+) channel activity and can potentially alleviate epileptiform activity.
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Affiliation(s)
- Ming-Yi Chou
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Chun-Yao Lee
- Department of Pharmacology and Neurology, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Horng-Huei Liou
- Department of Pharmacology and Neurology, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan.
| | - Chien-Yuan Pan
- Department of Life Science, National Taiwan University, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan.
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11
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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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