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Seiffert S, Pendziwiat M, Hedrich UBS, Helbig I, Weber Y, Schwarz N. KCNC2 variants of uncertain significance are also associated to various forms of epilepsy. Front Neurol 2023; 14:1212079. [PMID: 37360341 PMCID: PMC10289024 DOI: 10.3389/fneur.2023.1212079] [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: 04/25/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
Recently, de novo variants in KCNC2, coding for the potassium channel subunit KV3.2, have been described as causative for various forms of epilepsy including genetic generalized epilepsy (GGE) and developmental and epileptic encephalopathy (DEE). Here, we report the functional characteristics of three additional KCNC2 variants of uncertain significance and one variant classified as pathogenic. Electrophysiological studies were performed in Xenopus laevis oocytes. The data presented here support that KCNC2 variants with uncertain significance may also be causative for various forms of epilepsy, as they show changes in the current amplitude and activation and deactivation kinetics of the channel, depending on the variant. In addition, we investigated the effect of valproic acid on KV3.2, as several patients carrying pathogenic variants in the KCNC2 gene achieved significant seizure reduction or seizure freedom with this drug. However, in our electrophysiological investigations, no change on the behavior of KV3.2 channels could be observed, suggesting that the therapeutic effect of VPA may be explained by other mechanisms.
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Affiliation(s)
- Simone Seiffert
- Department of Human Genetics, University Hospital Ulm, Ulm, Germany
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Manuela Pendziwiat
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Kiel, Germany
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Christian-Albrechts-University, Kiel, Germany
| | - Ulrike B. S. Hedrich
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Ingo Helbig
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Christian-Albrechts-University, Kiel, Germany
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Yvonne Weber
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Epileptology and Neurology, University of Aachen, Aachen, Germany
| | - Niklas Schwarz
- Department of Neurology and Epileptology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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The Anti-Epileptic Drugs Lamotrigine and Valproic Acid Reduce the Cardiac Sodium Current. Biomedicines 2023; 11:biomedicines11020477. [PMID: 36831014 PMCID: PMC9953282 DOI: 10.3390/biomedicines11020477] [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: 01/03/2023] [Revised: 01/24/2023] [Accepted: 01/31/2023] [Indexed: 02/10/2023] Open
Abstract
Anti-epileptic drugs (AEDs) are associated with increased risk of sudden cardiac death. To establish whether gabapentin, lamotrigine, levetiracetam, pregabalin, and valproic acid reduce the Nav1.5 current, we conducted whole-cell patch-clamp studies to study the effects of the five AEDs on currents of human cardiac Nav1.5 channels stably expressed in HEK293 cells, and on action potential (AP) properties of freshly isolated rabbit ventricular cardiomyocytes. Lamotrigine and valproic acid exhibited inhibitory effects on the Nav1.5 current in a concentration-dependent manner with an IC50 of 142 ± 36 and 2022 ± 25 µM for lamotrigine and valproic acid, respectively. In addition, these drugs caused a hyperpolarizing shift of steady-state inactivation and a delay in recovery from inactivation. The changes on the Nav1.5 properties were reflected by a reduction in AP upstroke velocity (43.0 ± 6.8% (lamotrigine) and 23.7 ± 10.6% (valproic acid) at 1 Hz) and AP amplitude; in contrast, AP duration was not changed. Gabapentin, levetiracetam, and pregabalin had no effect on the Nav1.5 current. Lamotrigine and valproic acid reduce the Nav1.5 current density and affect its gating properties, resulting in a decrease of the AP upstroke velocity. Gabapentin, levetiracetam, and pregabalin have no effects on the Nav1.5 current.
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Kuanyshbek A, Wang M, Andersson Å, Tuifua M, Palmer EE, Sachdev RK, Mu TW, Vetter I, Keramidas A. Anti-seizure mechanisms of midazolam and valproate at the β2(L51M) variant of the GABA A receptor. Neuropharmacology 2022; 221:109295. [PMID: 36257447 PMCID: PMC9981329 DOI: 10.1016/j.neuropharm.2022.109295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022]
Abstract
Genetic sequencing is identifying an expanding number of variants of GABAA receptors associated with human epilepsies. We identified a new de novo variant of the β2 subunit (β2L51M) of the inhibitory GABAA receptor associated with seizures. Our analysis determined the pathogenicity of the variant and the effects of anti-seizure medications. Our data demonstrates that the variant reduced cell surface trafficking and peak GABA-gated currents. Synaptic currents mediated by variant-containing receptors decayed faster than wild-type and single receptor currents showed that the variant shortened the duration of receptor activity by decreasing receptor open times. We tested the effects of the anti-seizure medications, midazolam, carbamazepine and valproate and found that all three enhance variant receptor surface expression. Additionally, midazolam restored receptor function by increasing single receptor active periods and synaptic current decay times towards wild-type levels. By contrast, valproate increased synaptic peak currents, event frequency and promoted synaptic bursting. Our study identifies a new disease-causing variant to the GABAA receptor, profiles its pathogenic effects and demonstrates how anti-seizure drugs correct its functional deficits.
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Affiliation(s)
- Alibek Kuanyshbek
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Meng Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Åsa Andersson
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Marie Tuifua
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Elizabeth E Palmer
- Sydney Children's Hospital Network, Randwick Sydney Australia and School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, NSW, Australia
| | - Rani K Sachdev
- Sydney Children's Hospital Network, Randwick Sydney Australia and School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, NSW, Australia
| | - Ting-Wei Mu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, Queensland, 4102, Australia
| | - Angelo Keramidas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia.
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Mohammadkhani R, Ghahremani R, Salehi I, Safari S, Karimi SA, Zarei M. Impairment in social interaction and hippocampal long-term potentiation at perforant pathway-dentate gyrus synapses in a prenatal valproic acid-induced rat model of autism. Brain Commun 2022; 4:fcac221. [PMID: 36092302 PMCID: PMC9453432 DOI: 10.1093/braincomms/fcac221] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 07/02/2022] [Accepted: 09/01/2022] [Indexed: 11/30/2022] Open
Abstract
It is well established that prenatal valproic acid exposure in rats leads to autism-like behaviours and social deficits. Long-term potentiation changes in the brain have been proposed as a potential mechanism in the development of autistic behaviour. However, there are controversies regarding the effect of in utero valproic acid exposure on long-term potentiation. This study examined the social interaction and long-term potentiation induction in perforant pathway-dentate gyrus synapses in male offspring of a rat model of autism induced by prenatal exposure to valproic acid. On Embryonic Day 12.5, the pregnant dams received an injection of 500 mg/kg valproic acid (intraperitoneal) to produce the autism model. The sociability test was performed between Postnatal Days 37 and 40. The offsprings were urethane-anaesthetized and placed into a stereotaxic apparatus for surgery, electrode implantation and field potential recording on Postnatal Days 45–55. In the dentate gyrus region, excitatory postsynaptic potential slope and population spike amplitude were measured. Valproic acid-exposed offspring showed significantly impaired social interaction. The birth weight in valproic acid-exposed rats was significantly lower than in control rats. The ability of dentate gyrus synapses to induce long-term potentiation was hampered by valproic acid exposure. The decreasing excitatory postsynaptic potential slope and population spike amplitude of long-term potentiation provide evidence in favour of this notion. It is widely supposed that the hippocampus plays a central role in the process of learning and memory as well as social interaction and social memory. Therefore, deficiencies in hippocampal synaptic plasticity may be responsible, at least in part, for the social interaction deficits in valproic acid-exposed rats.
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Affiliation(s)
- Reihaneh Mohammadkhani
- Neurophysiology Research Center, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
| | - Reza Ghahremani
- Neurophysiology Research Center, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
- Department of Exercise Physiology, Faculty of Sport Sciences, University of Birjand , Birjand 9717434765 , Iran
| | - Iraj Salehi
- Neurophysiology Research Center, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
| | - Samaneh Safari
- Neurophysiology Research Center, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
- Department of Neuroscience, School of Science and Advanced Technologies in Medicine, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
| | - Seyed Asaad Karimi
- Neurophysiology Research Center, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
- Department of Neuroscience, School of Science and Advanced Technologies in Medicine, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
| | - Mohammad Zarei
- Neurophysiology Research Center, Hamadan University of Medical Sciences , Hamadan 65178/518 , Iran
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Mishra MK, Kukal S, Paul PR, Bora S, Singh A, Kukreti S, Saso L, Muthusamy K, Hasija Y, Kukreti R. Insights into Structural Modifications of Valproic Acid and Their Pharmacological Profile. MOLECULES (BASEL, SWITZERLAND) 2021; 27:molecules27010104. [PMID: 35011339 PMCID: PMC8746633 DOI: 10.3390/molecules27010104] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 11/16/2022]
Abstract
Valproic acid (VPA) is a well-established anticonvulsant drug discovered serendipitously and marketed for the treatment of epilepsy, migraine, bipolar disorder and neuropathic pain. Apart from this, VPA has potential therapeutic applications in other central nervous system (CNS) disorders and in various cancer types. Since the discovery of its anticonvulsant activity, substantial efforts have been made to develop structural analogues and derivatives in an attempt to increase potency and decrease adverse side effects, the most significant being teratogenicity and hepatotoxicity. Most of these compounds have shown reduced toxicity with improved potency. The simple structure of VPA offers a great advantage to its modification. This review briefly discusses the pharmacology and molecular targets of VPA. The article then elaborates on the structural modifications in VPA including amide-derivatives, acid and cyclic analogues, urea derivatives and pro-drugs, and compares their pharmacological profile with that of the parent molecule. The current challenges for the clinical use of these derivatives are also discussed. The review is expected to provide necessary knowledgebase for the further development of VPA-derived compounds.
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Affiliation(s)
- Manish Kumar Mishra
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi 110007, India; (M.K.M.); (S.K.); (P.R.P.); (S.B.)
- Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India;
| | - Samiksha Kukal
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi 110007, India; (M.K.M.); (S.K.); (P.R.P.); (S.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Priyanka Rani Paul
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi 110007, India; (M.K.M.); (S.K.); (P.R.P.); (S.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Shivangi Bora
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi 110007, India; (M.K.M.); (S.K.); (P.R.P.); (S.B.)
- Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India;
| | - Anju Singh
- Nucleic Acids Research Lab, Department of Chemistry, University of Delhi (North Campus), Delhi 110007, India; (A.S.); (S.K.)
- Department of Chemistry, Ramjas College, University of Delhi (North Campus), Delhi 110007, India
| | - Shrikant Kukreti
- Nucleic Acids Research Lab, Department of Chemistry, University of Delhi (North Campus), Delhi 110007, India; (A.S.); (S.K.)
| | - Luciano Saso
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy;
| | - Karthikeyan Muthusamy
- Department of Bioinformatics, Alagappa University, Karaikudi 630004, Tamil Nadu, India;
| | - Yasha Hasija
- Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India;
| | - Ritushree Kukreti
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Mall Road, Delhi 110007, India; (M.K.M.); (S.K.); (P.R.P.); (S.B.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
- Correspondence: or ; Tel.: +91-11-27662202; Fax: +91-11-27667471
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Singh D, Gupta S, Verma I, Morsy MA, Nair AB, Ahmed ASF. Hidden pharmacological activities of valproic acid: A new insight. Biomed Pharmacother 2021; 142:112021. [PMID: 34463268 DOI: 10.1016/j.biopha.2021.112021] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 07/28/2021] [Accepted: 08/07/2021] [Indexed: 12/24/2022] Open
Abstract
Valproic acid (VPA) is an approved drug for managing epileptic seizures, bipolar disorders, and migraine. VPA has been shown to elevate the level of gamma-aminobutyric acid (GABA) in the brain through competitive inhibition of GABA transaminase, thus promoting the availability of synaptic GABA and facilitating GABA-mediated responses. VPA, which is a small chain of fatty acids, prevents histone deacetylases (HDACs). HDACs play a crucial role in chromatin remodeling and gene expression through posttranslational changes of chromatin-associated histones. Recent studies reported a possible effect of VPA against particular types of cancers. This effect was partially attributed to its role in regulating epigenetic modifications through the inhibition of HDACs, which affect the expression of genes associated with cell cycle control, cellular differentiation, and apoptosis. In this review, we summarize the current information on the actions of VPA in diseases such as diabetes mellitus, kidney disorders, neurodegenerative diseases, muscular dystrophy, and cardiovascular disorders.
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Affiliation(s)
- Dhirendra Singh
- Department of Pharmacology, M.M. College of Pharmacy, M.M. (Deemed to be University), Mullana, Ambala, Haryana, India
| | - Sumeet Gupta
- Department of Pharmacology, M.M. College of Pharmacy, M.M. (Deemed to be University), Mullana, Ambala, Haryana, India.
| | - Inderjeet Verma
- Department of Pharmacology, M.M. College of Pharmacy, M.M. (Deemed to be University), Mullana, Ambala, Haryana, India
| | - Mohamed A Morsy
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa, Saudi Arabia; Department of Pharmacology, Faculty of Medicine, Minia University, El-Minia, Egypt
| | - Anroop B Nair
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa, Saudi Arabia
| | - Al-Shaimaa F Ahmed
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Minia University, El-Minia, Egypt
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Mishra P, Sinha JK, Rajput SK. Efficacy of Cicuta virosa medicinal preparations against pentylenetetrazole-induced seizures. Epilepsy Behav 2021; 115:107653. [PMID: 33358679 DOI: 10.1016/j.yebeh.2020.107653] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/03/2020] [Accepted: 11/19/2020] [Indexed: 12/15/2022]
Abstract
Epileptic seizures are characterized by imbalanced inhibition-excitation cycle that triggers biochemical alterations responsible for jeopardized neuronal integrity. Conventional antiepileptic drugs (AEDs) have been the mainstay option for treatment and control; however, symptomatic control and potential to exacerbate the seizure condition calls for viable alternative to these chemical agents. In this context, natural product-based therapies have accrued great interest in recent years due to competent disease management potential and lower associated adversities. Cicuta virosa (CV) is one such herbal remedy that is used in traditional system of medicine against myriad of disorders including epilepsy. Homeopathic medicinal preparations (HMPs) of CV were assessed for their efficacy in pentylenetetrazole (PTZ)-induced acute and kindling models of epilepsy. CV HMPs increased the latency and reduced the duration of tonic-clonic phase in acute model while lowering the kindling score in the kindling model that signified their role in modulating GABAergic neurotransmission and potassium conductance. Kindling-induced impairment of cognition, memory, and motor coordination was ameliorated by the CV HMPs that substantiated their efficacy in imparting sustained neuronal fortification. Furthermore, biochemical evaluation showed attenuated oxidative stress load through reduced lipid peroxidation and strengthened free radical scavenging mechanism. Taken together, CV HMPs exhibited promising results in acute and kindling models and must be further assessed through molecular and epigenomic studies.
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Affiliation(s)
- Priya Mishra
- Amity Institute of Neuropsychology and Neurosciences (AINN), Amity University, Uttar Pradesh, Noida 201303, India.
| | - Jitendra Kumar Sinha
- Amity Institute of Neuropsychology and Neurosciences (AINN), Amity University, Uttar Pradesh, Noida 201303, India.
| | - Satyendra Kumar Rajput
- Department of Pharmaceutical Sciences, Gurukul Kangri (deemed to be University), Haridwar, Uttrakhand, 249404, India.
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Mekky G, Seeds M, Diab AEAA, Shehata AM, Ahmed-Farid OAH, Alzebdeh D, Bishop C, Atala A. The potential toxic effects of magnesium oxide nanoparticles and valproate on liver tissue. J Biochem Mol Toxicol 2020; 35:e22676. [PMID: 33315275 DOI: 10.1002/jbt.22676] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/24/2020] [Accepted: 12/03/2020] [Indexed: 02/02/2023]
Abstract
The liver is the main organ responsible for drug and xenobiotic metabolism and detoxification in the body. There are many antiepileptic drugs and nanoparticles that have been reported to cause serious untoward biological responses and hepatotoxicity. The aim of this study is to investigate the potential toxic effect of aspartic acid-coated magnesium oxide nanoparticles (Mg nano) and valproate (valp) using an in vitro three-dimensional (3D) human liver organoid model and an in vivo pentylenetetrazole (PTZ)-induced convulsion model in rats. Here, 3D human liver organoids were treated with valp or valp + Mg nano for 24 h and then incubated with PTZ for an extra 24 h. As the in vivo model, rats were treated with valp, Mg nano, or valp + Mg nano for 4 weeks and then they were treated with PTZ for 24 h. Toxicity in the liver organoids was demonstrated by reduced cell viability, decreased ATP, and increased reactive oxygen species. In the rat convulsion model, results revealed elevated serum alanine aminotransferase and aspartate aminotransferase levels. Both the in vitro and in vivo data demonstrated the potential toxic effects of valp + Mg nano on the liver tissues.
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Affiliation(s)
- Gehad Mekky
- Zoology Department, Faculty of Science, Zagazige, Egypt.,Wake Forest Institute for Regenerative Medicine, Winston-Salem, North Carolina, USA
| | - Michael Seeds
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, North Carolina, USA
| | | | - Ahmed M Shehata
- Physiology Department, National Organization for Drug Control and Research (NODCAR), Giza, Egypt
| | - Omar A-H Ahmed-Farid
- Physiology Department, National Organization for Drug Control and Research (NODCAR), Giza, Egypt
| | - Dalia Alzebdeh
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, North Carolina, USA
| | - Colin Bishop
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, North Carolina, USA
| | - Anthony Atala
- Wake Forest Institute for Regenerative Medicine, Winston-Salem, North Carolina, USA
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Valproate Sodium Protects Blood Brain Barrier Integrity in Intracerebral Hemorrhage Mice. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:8884320. [PMID: 33224434 PMCID: PMC7676278 DOI: 10.1155/2020/8884320] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/28/2020] [Accepted: 10/15/2020] [Indexed: 01/04/2023]
Abstract
Valproate sodium (VPA) is a traditional antiepileptic drug with a neuroprotective role in cerebrovascular disease. After intracerebral hemorrhage (ICH), mechanical compression by hematoma, neuroinflammation, oxidative stress, and cytotoxicity of hematoma lysates caused the destruction of the blood brain barrier (BBB). Targeting BBB is a major therapeutic method for patients with ICH. The purpose of the present study was to explore the role of VPA in preserving BBB integrity in the ICH model and investigate the underlying molecular mechanisms. One hundred and thirty-six adult male CD1 mice were randomly divided into five groups in the study. Mice subjected to ICH were administered intraperitoneally with VPA at 3, 24, and 48 h post-ICH, respectively. Neurobehavioral assessments, BBB permeability, Evans blue fluorescence, hematoma volume, and protein expression were evaluated. The administration of VPA reduced BBB permeability and improved the neurobehavior significantly post-ICH. VPA administration significantly decreased the expression of phosphorylated nuclear factor-kappa B (p-NFκB), matrix metalloproteinases 9 (MMP9), tumor necrosis factorα (TNFα), and interleukin-6 (IL-6), while it enhanced the expression of claudin 5 and occludin in the brain. In conclusion, VPA administration maintained the integrity of BBB after experimental ICH, thus reducing brain edema and improving the neurological outcomes. Therefore, VPA administration might be a new therapeutic method to protect BBB integrity for patients with ICH.
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Abstract
Myoclonus can cause significant disability for patients. Myoclonus has a strikingly diverse array of underlying etiologies, clinical presentations, and pathophysiological mechanisms. Treatment of myoclonus is vital to improving the quality of life of patients with these disorders. The optimal treatment strategy for myoclonus is best determined based upon careful evaluation and consideration of the underlying etiology and neurophysiological classification. Electrophysiological testing including EEG (electroencephalogram) and EMG (electromyogram) data is helpful in determining the neurophysiological classification of myoclonus. The neurophysiological subtypes of myoclonus include cortical, cortical-subcortical, subcortical-nonsegmental, segmental, and peripheral. Levetiracetam, valproic acid, and clonazepam are often used to treat cortical myoclonus. In cortical-subcortical myoclonus, treatment of myoclonic seizures is prioritized, valproic acid being the mainstay of therapy. Subcortical-nonsegmental myoclonus may be treated with clonazepam, though numerous agents have been used depending on the etiology. Segmental and peripheral myoclonus are often resistant to treatment, but anticonvulsants and botulinum toxin injections may be of utility depending upon the case. Pharmacological treatments are often hampered by scarce evidence-based knowledge, adverse effects, and variable efficacy of medications.
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Affiliation(s)
- Ashley B. Pena
- Department of Neurology, Mayo Clinic Florida, 4500 San Pablo Rd S, Jacksonville, Florida 32224 USA
| | - John N. Caviness
- Department of Neurology, Mayo Clinic Arizona, 13400 East Shea Blvd., Scottsdale, Arizona 85259 USA
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An investigation on the effects of carbamazepine and sodium valproate on neuromuscular transmission. Acta Neurol Belg 2020; 120:545-548. [PMID: 28940165 DOI: 10.1007/s13760-017-0839-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
The aim of this study was to investigate the effects of sodium valproate (SV) and carbamazepine (CBZ) on neuromuscular transmission using single-fibre electromyography (SFEMG) in patients with epilepsy. We performed SFEMG during the voluntary contraction of extensor digitorum communis muscle. 30 epileptic patients taking SV, 25 epileptic patients taking CBZ, and 25 age-matched healthy volunteers were included in the study. Mean jitter values (MCD) of subjects taking SV and CBZ were compared with normal controls. MCD values of subjects taking SV and CBZ were statistically significantly higher than those of control group. Review of the correlation between disease duration and MCD values of patients showed that MCD values were increased with the prolonged use of drugs, and thus, indicated a positive relationship between these two parameters. These results suggest that both SV and CBZ reduce neuromuscular transmission in patients without a neuromuscular junction disease.
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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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Valproic acid interactions with the NavMs voltage-gated sodium channel. Proc Natl Acad Sci U S A 2019; 116:26549-26554. [PMID: 31822620 DOI: 10.1073/pnas.1909696116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Valproic acid (VPA) is an anticonvulsant drug that is also used to treat migraines and bipolar disorder. Its proposed biological targets include human voltage-gated sodium channels, among other membrane proteins. We used the prokaryotic NavMs sodium channel, which has been shown to be a good exemplar for drug binding to human sodium channels, to examine the structural and functional interactions of VPA. Thermal melt synchrotron radiation circular dichroism spectroscopic binding studies of the full-length NavMs channel (which includes both pore and voltage sensor domains), and a pore-only construct, undertaken in the presence and absence of VPA, indicated that the drug binds to and destabilizes the channel, but not the pore-only construct. This is in contrast to other antiepileptic compounds that have previously been shown to bind in the central hydrophobic core of the pore region of the channel, and that tend to increase the thermal stability of both pore-only constructs and full-length channels. Molecular docking studies also indicated that the VPA binding site is associated with the voltage sensor, rather than the hydrophobic cavity of the pore domain. Electrophysiological studies show that VPA influences the block and inactivation rates of the NavMs channel, although with lower efficacy than classical channel-blocking compounds. It thus appears that, while VPA is capable of binding to these voltage-gated sodium channels, it has a very different mode and site of action than other anticonvulsant compounds.
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Buch D, Chabriat H. Lamotrigine in the Prevention of Migraine With Aura: A Narrative Review. Headache 2019; 59:1187-1197. [PMID: 31468532 DOI: 10.1111/head.13615] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2019] [Indexed: 01/03/2023]
Abstract
BACKGROUND Lamotrigine is not recommended in the prevention of migraine in general but some reports suggest that it might be effective for treating specifically migraine with aura (MA). This review aims to summarize the related data from the literature and to better understand this discrepancy. METHODS All reports from the literature related to the use of lamotrigine in migraine with or without aura published prior to February 2019 found using PUBMED and the 2 keywords "migraine" AND "lamotrigine" were reviewed. Original studies, published in full, systematic reviews, and all case reports were synthetized. We also examined the risk profile, pharmacokinetics, and mode of action of lamotrigine in view of the presumed mechanism of MA. RESULTS Lamotrigine was tested in different populations of migraineurs, but previous studies had small sample sizes (n < 35) and might not have been powered enough for detecting a potential benefit of lamotrigine in MA. Accumulating data suggest that the drug can reduce both the frequency and severity of aura symptoms in multiple conditions and is well tolerated. CONCLUSION Lamotrigine appears promising for treating attacks of MA and related clinical manifestations because of its high potential of efficacy, low-risk profile, and cost. Additional studies are needed for testing lamotrigine in patients with MA.
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Affiliation(s)
- Dan Buch
- Neurology Department, DHU Neuro-Vasc, Hopital Lariboisière, Paris, France
| | - Hugues Chabriat
- Neurology Department, DHU Neuro-Vasc, Hopital Lariboisière, Paris, France.,INSERM U1161, Université Denis Diderot, Paris, France
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Exploring the Drug Repurposing Versatility of Valproic Acid as a Multifunctional Regulator of Innate and Adaptive Immune Cells. J Immunol Res 2019; 2019:9678098. [PMID: 31001564 PMCID: PMC6437734 DOI: 10.1155/2019/9678098] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/30/2018] [Accepted: 01/02/2019] [Indexed: 12/11/2022] Open
Abstract
Valproic acid (VPA) is widely recognized for its use in the control of epilepsy and other neurological disorders in the past 50 years. Recent evidence has shown the potential of VPA in the control of certain cancers, owed in part to its role in modulating epigenetic changes through the inhibition of histone deacetylases, affecting the expression of genes involved in the cell cycle, differentiation, and apoptosis. The direct impact of VPA in cells of the immune system has only been explored recently. In this review, we discuss the effects of VPA in the suppression of some activation mechanisms in several immune cells that lead to an anti-inflammatory response. As expected, immune cells are not exempt from the effect of VPA, as it also affects the expression of genes of the cell cycle and apoptosis through epigenetic modifications. In addition to inhibiting histone deacetylases, VPA promotes RNA interference, activates histone methyltransferases, or represses the activation of transcription factors. However, during the infectious process, the effectiveness of VPA is subject to the biological nature of the pathogen and the associated immune response; this is because VPA can promote the control or the progression of the infection. Due to its various effects, VPA is a promising alternative for the control of autoimmune diseases and hypersensitivity and needs to be further explored.
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16
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The pharmacogenomics of valproic acid. J Hum Genet 2017; 62:1009-1014. [PMID: 28878340 DOI: 10.1038/jhg.2017.91] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 08/02/2017] [Accepted: 08/02/2017] [Indexed: 11/08/2022]
Abstract
Valproic acid is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder. Adverse effects of valproic acid are rare, but hepatotoxicity is severe in particular in those younger than 2 years old and polytherapy. During valproic acid treatment, it is difficult for prescribers to predict its individual response. Recent advances in the field of pharmacogenomics have indicated variants of candidate genes that affect valproic acid efficacy and safety. In this review, a large number of candidate genes that influence valproic acid pharmacokinetics and pharmacodynamics are discussed, including metabolic enzymes, drug transporters, neurotransmitters and drug targets. Furthermore, pharmacogenomics is an important tool not only in further understanding of interindividual variability but also to assess the therapeutic potential of such variability in drug individualization and therapeutic optimization.
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Powell KL, Cain SM, Snutch TP, O'Brien TJ. Low threshold T-type calcium channels as targets for novel epilepsy treatments. Br J Clin Pharmacol 2015; 77:729-39. [PMID: 23834404 DOI: 10.1111/bcp.12205] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 07/02/2013] [Indexed: 12/21/2022] Open
Abstract
Low voltage-activated T-type calcium channels were originally cloned in the 1990s and much research has since focused on identifying the physiological roles of these channels in health and disease states. T-type calcium channels are expressed widely throughout the brain and peripheral tissues, and thus have been proposed as therapeutic targets for a variety of diseases such as epilepsy, insomnia, pain, cancer and hypertension. This review discusses the literature concerning the role of T-type calcium channels in physiological and pathological processes related to epilepsy. T-type calcium channels have been implicated in pathology of both the genetic and acquired epilepsies and several anti-epileptic drugs (AEDs) in clinical use are known to suppress seizures via inhibition of T-type calcium channels. Despite the fact that more than 15 new AEDs have become clinically available over the past 20 years at least 30% of epilepsy patients still fail to achieve seizure control, and many patients experience unwanted side effects. Furthermore there are no treatments that prevent the development of epilepsy or mitigate the epileptic state once established. Therefore there is an urgent need for the development of new AEDs that are effective in patients with drug resistant epilepsy, are anti-epileptogenic and are better tolerated. We also review the mechanisms of action of the current AEDs with known effects on T-type calcium channels and discuss novel compounds that are being investigated as new treatments for epilepsy.
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Affiliation(s)
- Kim L Powell
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
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Kimura A, Namekata K, Guo X, Noro T, Harada C, Harada T. Valproic acid prevents NMDA-induced retinal ganglion cell death via stimulation of neuronal TrkB receptor signaling. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 185:756-64. [PMID: 25542970 DOI: 10.1016/j.ajpath.2014.11.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 11/04/2014] [Accepted: 11/10/2014] [Indexed: 12/27/2022]
Abstract
Valproic acid (VPA) is widely prescribed for treatment of epilepsy, mood disorders, migraines, and neuropathic pain. It exerts its therapeutic benefits through multiple mechanisms, including enhancement of GABAergic activity, activation of prosurvival protein kinases, and inhibition of histone deacetylase. Increasing evidence suggests that VPA possesses neuroprotective properties. We examined neuroprotective effects of VPA in an N-methyl-d-aspartate (NMDA) excitotoxicity model, which mimics some of the pathological features of glaucoma. In vivo retinal imaging using optical coherence tomography revealed that NMDA-induced retinal degeneration was suppressed in the VPA-treated retina, and histological analyses confirmed that VPA reduced retinal ganglion cell death. In vivo electrophysiological analyses demonstrated that visual impairment was prevented in the VPA-treated retina, clearly establishing both histological and functional effects of VPA. Brain-derived neurotrophic factor (BDNF) expression was up-regulated in Müller glial cells, and neuroprotective effects of VPA on retinal ganglion cells were significantly reduced in a conditional knockout mouse strain with deletion of tropomyosin receptor kinase B (TrkB), a receptor for BDNF from retinal ganglion cells. The results show that VPA stimulates BDNF up-regulation in Müller glial cells and provides direct evidence that neuronal TrkB is important in VPA-mediated neuroprotection. Also, VPA suppresses oxidative stress induced by NMDA in the retina. Our findings raise intriguing possibilities that the widely prescribed drug VPA may be useful for treatment of glaucoma.
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Affiliation(s)
- Atsuko Kimura
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Xiaoli Guo
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takahiko Noro
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takayuki Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
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Trécul A, Morceau F, Gaigneaux A, Schnekenburger M, Dicato M, Diederich M. Valproic acid regulates erythro-megakaryocytic differentiation through the modulation of transcription factors and microRNA regulatory micro-networks. Biochem Pharmacol 2014; 92:299-311. [DOI: 10.1016/j.bcp.2014.07.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 07/10/2014] [Accepted: 07/14/2014] [Indexed: 10/24/2022]
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Abstract
Myoclonus creates significant disability for patients. This symptom or sign can have many different etiologies, presentations, and pathophysiological mechanisms. A thorough evaluation for the myoclonus etiology is critical for developing a treatment strategy. The best etiological classification scheme is a modified version from that proposed by Marsden et al. in 1982. Clinical neurophysiology, as assessed by electromyography and electroencephalography, can be used to classify the pathophysiology of the myoclonus using a neurophysiology classification scheme. If the etiology of the myoclonus cannot be reversed or treated, then symptomatic treatment of the myoclonus itself may be warranted. Unfortunately, there are few controlled studies for myoclonus treatments. The treatment strategy for the myoclonus is best derived from the neurophysiology classification scheme categories: 1) cortical, 2) cortical-subcortical, 3) subcortical-nonsegmental, 4) segmental, and 5) peripheral. A cortical physiology classification is most common. Levetiracetam is suggested as first-line treatment for cortical myoclonus, but valproic acid and clonazepam are commonly used. Cortical-subcortical myoclonus is the physiology demonstrated by myoclonic seizures, such as in primary epileptic myoclonus (e.g., juvenile myoclonic epilepsy). Valproic acid has demonstrated efficacy in such epileptic syndromes with other medications providing an adjunctive role. Clonazepam is used for subcortical-nonsegmental myoclonus, but other treatments, depending on the syndrome, have been used for this physiological type of myoclonus. Segmental myoclonus is difficult to treat, but clonazepam and botulinum toxin are used. Botulinum toxin is used for focal examples of peripheral myoclonus. Myoclonus treatment is commonly not effective and/or limited by side effects.
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Affiliation(s)
- John N Caviness
- Department of Neurology, Mayo Clinic Arizona, 13400 East Shea Blvd., Scottsdale, AZ, 85259, USA,
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Valproate Disturbs the Balance Between Branched and Aromatic Amino Acids in Rats. Neurotox Res 2013; 25:358-68. [DOI: 10.1007/s12640-013-9441-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 11/05/2013] [Accepted: 11/06/2013] [Indexed: 10/26/2022]
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Moldrich RX, Leanage G, She D, Dolan-Evans E, Nelson M, Reza N, Reutens DC. Inhibition of histone deacetylase in utero causes sociability deficits in postnatal mice. Behav Brain Res 2013; 257:253-64. [DOI: 10.1016/j.bbr.2013.09.049] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 09/23/2013] [Accepted: 09/27/2013] [Indexed: 01/08/2023]
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23
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Tonk ECM, Robinson JF, Verhoef A, Theunissen PT, Pennings JLA, Piersma AH. Valproic acid-induced gene expression responses in rat whole embryo culture and comparison across in vitro developmental and non-developmental models. Reprod Toxicol 2013; 41:57-66. [PMID: 23811354 DOI: 10.1016/j.reprotox.2013.06.069] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 05/31/2013] [Accepted: 06/07/2013] [Indexed: 11/26/2022]
Abstract
Transcriptomic evaluations may improve toxicity prediction of in vitro-based developmental models. In this study, transcriptomics was used to identify VPA-induced gene expression changes in rat whole embryo culture (WEC). Furthermore, VPA-induced responses were compared across in vitro-based developmental models, such as the cardiac and neural embryonic stem cells (ESTc and ESTn, respectively) and the zebrafish embryotoxicity model. VPA-induced gene regulation in WEC corresponded with observed morphological effects and previously suggested mechanisms of toxicity. Gene Ontology term-directed analysis showed conservation of VPA-induced gene expression changes across in vitro-based developmental models, with ESTc and ESTn exhibiting complementary responses. Furthermore, comparison of in vitro-based developmental and non-developmental models revealed that more generalized VPA-induced effects can be detected using non-developmental models whereas developmental models provide added value when assessing developmental-specific effects. These analyses can be used to optimize test batteries for the detection of developmental toxicants in vitro.
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Affiliation(s)
- Elisa C M Tonk
- Centre for Health Protection, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.
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The kynurenine pathway: A missing piece in the puzzle of valproate action? Neuroscience 2013; 234:135-45. [DOI: 10.1016/j.neuroscience.2012.12.052] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/17/2012] [Accepted: 12/21/2012] [Indexed: 11/18/2022]
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Christian Machado Ximenes J, Crisóstomo Lima Verde E, da Graça Naffah-Mazzacoratti M, Socorro de Barros Viana G. Valproic Acid, a Drug with Multiple Molecular Targets Related to Its Potential Neuroprotective Action. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/nm.2012.31016] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Porter RJ, Dhir A, Macdonald RL, Rogawski MA. Mechanisms of action of antiseizure drugs. HANDBOOK OF CLINICAL NEUROLOGY 2012; 108:663-681. [PMID: 22939059 DOI: 10.1016/b978-0-444-52899-5.00021-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Roger J Porter
- Department of Neurology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Valproic acid antagonizes the capacity of other histone deacetylase inhibitors to activate the Epstein-barr virus lytic cycle. J Virol 2011; 85:5628-43. [PMID: 21411522 DOI: 10.1128/jvi.02659-10] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Diverse stimuli reactivate the Epstein-Barr virus (EBV) lytic cycle in Burkitt lymphoma (BL) cells. In HH514-16 BL cells, two histone deacetylase (HDAC) inhibitors, sodium butyrate (NaB) and trichostatin A (TSA), and the DNA methyltransferase inhibitor azacytidine (AzaCdR) promote lytic reactivation. Valproic acid (VPA), which, like NaB, belongs to the short-chain fatty acid class of HDAC inhibitors, fails to induce the EBV lytic cycle in these cells. Nonetheless, VPA behaves as an HDAC inhibitor; it causes hyperacetylation of histone H3 (J. K. Countryman, L. Gradoville, and G. Miller, J. Virol. 82:4706-4719, 2008). Here we show that VPA blocked the induction of EBV early lytic proteins ZEBRA and EA-D in response to NaB, TSA, or AzaCdR. The block in lytic activation occurred prior to the accumulation of BZLF1 transcripts. Reactivation of EBV in Akata cells, in response to anti-IgG, and in Raji cells, in response to tetradecanoyl phorbol acetate (TPA), was also inhibited by VPA. MS-275 and apicidin, representing two additional classes of HDAC inhibitors, and suberoylanilide hydroxamic acid (SAHA) reactivated EBV in HH514-16 cells; this activity was also inhibited by VPA. Although VPA potently blocked the expression of viral lytic-cycle transcripts, it did not generally block the transcription of cellular genes and was not toxic. The levels and kinetics of specific cellular transcripts, such as Stat3, Frmd6, Mad1, Sepp1, c-fos, c-jun, and egr1, which were activated by NaB and TSA, were similar in HH514-16 cells treated with VPA. When combined with NaB or TSA, VPA did not inhibit the activation of these cellular genes. Changes in cellular gene expression in response to VPA, NaB, or TSA were globally similar as assessed by human genome arrays; however, VPA selectively stimulated the expression of some cellular genes, such as MEF2D, YY1, and ZEB1, that could repress the EBV lytic cycle. We describe a novel example of functional antagonism between HDAC inhibitors.
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Englund M, Hyllienmark L, Brismar T. Effect of valproate, lamotrigine and levetiracetam on excitability and firing properties of CA1 neurons in rat brain slices. Cell Mol Neurobiol 2011; 31:645-52. [PMID: 21336651 DOI: 10.1007/s10571-011-9660-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Accepted: 02/02/2011] [Indexed: 11/27/2022]
Abstract
The purpose of this study was to analyze the rapid effects of the antiepileptic drugs valproate, lamotrigine, and levetiracetam on excitability and firing properties of hippocampal neurons. The drug effects on resting potential, action potential, and repetitive firing properties were studied in whole-cell current-clamp recordings of CA1 neurons in rat brain slices. Lamotrigine changed action potential rising slope by -24 ± 38 V/s (mean ± SD), peak amplitude by -6.8 ± 5.0 mV, and maximum firing frequency by -60 ± 13%. Lamotrigine thereto increased the voltage threshold by 4.3 ± 4.2 mV and augmented the action potential attenuation during repetitive firing. All effects were significant (P < 0.01 to P < 0.0002) compared to control cells. Valproate and levetiracetam showed no significant effects on these parameters. None of the tested drugs had a significant effect on the resting potential. The lamotrigine effects are consistent with sodium channel blocking which may explain or contribute to the antiepileptic mode of action. Valproate and levetiracetam did not show these effects and the mechanism of their antiepileptic action need to be different. These findings (valproate) differ in some respects from findings reported in cultured or dissociated neurons. In a slice where the neurons have largely preserved connections, drug effects are likely to be more similar to the therapeutic action in the brain.
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Affiliation(s)
- Marita Englund
- Department of Clinical Neuroscience, Section of Clinical Neurophysiology, Karolinska Institutet, 171 76, Stockholm, Sweden
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Molecular and therapeutic potential and toxicity of valproic acid. J Biomed Biotechnol 2010; 2010. [PMID: 20798865 PMCID: PMC2926634 DOI: 10.1155/2010/479364] [Citation(s) in RCA: 280] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 05/03/2010] [Accepted: 06/06/2010] [Indexed: 12/13/2022] Open
Abstract
Valproic acid (VPA), a branched short-chain fatty acid, is widely used as an antiepileptic drug and a mood stabilizer. Antiepileptic properties have been attributed to inhibition of Gamma Amino Butyrate (GABA) transaminobutyrate and of ion channels. VPA was recently classified among the Histone Deacetylase Inhibitors, acting directly at the level of gene transcription by inhibiting histone deacetylation and making transcription sites more accessible. VPA is a widely used drug, particularly for children suffering from epilepsy. Due to the increasing number of clinical trials involving VPA, and interesting results obtained, this molecule will be implicated in an increasing number of therapies. However side effects of VPA are substantially described in the literature whereas they are poorly discussed in articles focusing on its therapeutic use. This paper aims to give an overview of the different clinical-trials involving VPA and its side effects encountered during treatment as well as its molecular properties.
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Wu P, Jiang L, Chen H. Sodium valproate at the therapeutic concentration inhibits the induction but not the maintenance phase of long-term potentiation in rat hippocampal CA1 area. Biochem Biophys Res Commun 2010; 391:582-6. [DOI: 10.1016/j.bbrc.2009.11.102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Accepted: 11/17/2009] [Indexed: 11/26/2022]
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Yong W, Zhang MM, Wang S, Ruan DY. Effects of sodium valproate on synaptic transmission and neuronal excitability in rat hippocampus. Clin Exp Pharmacol Physiol 2009; 36:1062-7. [PMID: 19413604 DOI: 10.1111/j.1440-1681.2009.05186.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Valproate (VPA) has long been used in the treatment of both generalized and partial seizures. However, its cellular mechanisms of action remain unclear. 2. In the present study, the effects of VPA on synaptic transmission and neuronal excitability were examined in the hippocampal CA1 region using whole-cell patch clamp recordings. 3. Perfusion with VPA, at therapeutically attainable concentrations (i.e. 0.3 and 0.6 mmol/L), significantly increased the frequency (112 +/- 2 and 133 +/- 2% of control, respectively; n = 5; both P < 0.05), but not the average amplitude, of miniature inhibitory post-synaptic currents (mIPSCs). Perfusion with VPA had no effect on either the amplitude or the frequency of miniature excitatory post-synaptic currents (mEPSCs). 4. In acutely dissociated CA1 pyramidal neurons, VPA had no effect on 10 micromol/L GABA-induced currents. Furthermore, following the administration of 0.3 and 0.6 mmol/L VPA, the frequency of action potential firing was significantly reduced from 18.0 +/- 1.1 to 15.3 +/- 0.9 and from 18.6 +/- 0.9 to 12.6 +/- 0.6, respectively (n = 8; both P < 0.05). In contrast, 0.3 and 0.6 mmol/L VPA significantly increased spike frequency adaptation from 4.02 +/- 0.47 to 4.72 +/- 0.55 and from 3.47 +/- 0.41 to 4.48 +/- 0.58, respectively (n = 8; P < 0.05). 5. The results of the present study suggest that VPA presynaptically increases inhibitory synaptic activity without modifying excitatory synaptic transmission and reduces neuronal excitability. Any or all of these effects may contribute to its anticonvulsant action.
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Affiliation(s)
- Wu Yong
- Department of Neurobiology and Biophysics, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, PR China
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From ion channels to complex networks: Magic bullet versus magic shotgun approaches to anticonvulsant pharmacotherapy. Med Hypotheses 2009; 72:297-305. [PMID: 19046822 DOI: 10.1016/j.mehy.2008.09.049] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2008] [Revised: 08/05/2008] [Accepted: 09/18/2008] [Indexed: 01/15/2023]
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Hamed SA. The aspects and mechanisms of cognitive alterations in epilepsy: the role of antiepileptic medications. CNS Neurosci Ther 2009; 15:134-56. [PMID: 19254331 PMCID: PMC6494068 DOI: 10.1111/j.1755-5949.2008.00062.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Epilepsy is a major health problem. Several studies suggest a significant influence of epilepsy and its treatment on dynamic and functional properties of brain activity. Epilepsy can adversely affect mental development, cognition, and behavior. Epileptic patients may experience reduced intelligence, attention, and problems in memory, language, and frontal executive functions. Neuropsychological, functional, and quantitative neuroimaging studies revealed that epilepsy affect the brain as a whole. Mechanisms of epilepsy-related cognitive dysfunction are poorly delineated. Cognitive deficits with epilepsy may be transient, persistent, or progressive. Transient disruption of cognitive encoding processes may occur with paroxysmal focal or generalized epileptic discharges, whereas epileptogenesis-related neuronal plasticity, reorganization, sprouting, and impairment of cellular metabolism are fundamental determinants for progressive cognitive deterioration. Also antiepileptic drugs (AEDs) have differential, reversible, and sometimes cumulative cognitive adverse consequences. AEDs not only reduce neuronal irritability but also may impair neuronal excitability, neurotransmitter release, enzymes, and factors critical for information processing and memory. The present article serves as an overview of recent studies in adult and childhood epilepsy literatures present in PubMed that highlighted cognitive evaluation in epilepsy field (publications till 2008 were checked). We also checked the reference lists of the retrieved studies for additional reports of relevant studies, in addition to our experience in this field. Our search revealed that although the aspects of cognitive dysfunction, risk factors, and consequences have been explored in many studies; however, the mechanisms of contribution of epilepsy-related variables, including AEDs, to patients' cognition are largely unexplored. In this review, we discussed the differential effect of AEDs in mature and immature brains and the known mechanisms underlying epilepsy and AEDs adverse effects on cognition. The nature, timing, course, and mechanisms of cognitive alteration with epilepsy and its medications are of considerable clinical and research implications.
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Affiliation(s)
- Sherifa A Hamed
- Department of Neurology and Psychiatry, Assiut University Hospital, Assiut, Egypt.
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Shehata GA, Bateh AEAM, Hamed SA, Rageh TA, Elsorogy YB. Neuropsychological effects of antiepileptic drugs (carbamazepine versus valproate) in adult males with epilepsy. Neuropsychiatr Dis Treat 2009; 5:527-33. [PMID: 19898666 PMCID: PMC2773283 DOI: 10.2147/ndt.s5903] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Indexed: 11/23/2022] Open
Abstract
PURPOSE To evaluate the effect of antiepileptic drugs (AEDs) on cognition and behavior in adult epileptic males controlled on treatment with conventional antiepileptic medications. METHODS Cognitive, mood, behavior and personality traits were assessed in 45 epileptic patients treated with carbamazepine and/or valproate and free of seizures for >/=1 year. Thirty-four newly diagnosed or untreated patients with epilepsy and 58 matched healthy subjects were also included for comparison. A battery of psychometric tests was utilized including Stanford-Binet (4th edition), Beck Inventory for Depression, Aggressive Scale and Eysenck Personality Questionnaire. RESULTS Compared to matched control subjects, treated and untreated epileptic patients had poor performance in different cognitive and behavioral functions testing. Treated patients had worse scores in memory for digits forward and backward, total short-term memory, extroversion and psychosis. The duration of AEDs intake was correlated with memory of objects (r = -0.323; P = 0.030), bead memory (r = -0.314; P = 0.036) and total nonverbal short-term memory (r = -0.346; P = 0.020). Treated and untreated epileptic patients had poor performance of similar extent in behavioral functions testing (depression, aggression and neurosis). The dose of AEDs was correlated with testing scores for neurosis (r = 0.307; P = 0.040), verbal aggression (r = 0.483; P = 0.001) and nonverbal aggression (r = 0.526; P = 0.000), and duration of drug intake was correlated with scores for depression (r = 0.384; P = 0.009), psychosis (r = 0.586; P = 0.0001) and nonverbal aggression (r = 0.300; P = 0.045). CONCLUSIONS This study provides support for the notion that AEDs can impair performance in cognition, mood and behavior. Duration of drug intake and the number of the utilized AEDs are the main confounding variables. This study did not provide clues on how to exclude the effect of epilepsy itself and psychosocial variables as additional important confounding variables.
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Affiliation(s)
- Ghaydaa A Shehata
- Department of Neurology and Psychiatry, Faculty of Medicine, Assiut University, Egypt.
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Evaluation of conduction properties of somatic and sympathetic sudomotor fibers in patients with epilepsy. J Clin Neurophysiol 2008; 25:287-92. [PMID: 18791477 DOI: 10.1097/wnp.0b013e318182d32c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
To assess the function of fast somatic nerve fibers and sympathetic sudomotor system in patients with partial or generalized seizures, receiving various therapeutic regimes. The authors studied 60 patients (mean age 36.7 +/- 12.5 years) and 60 matched healthy controls by clinical, conventional nerve conduction study, and sympathetic skin responses (SSR) from hand and foot. Compared with controls, patients showed a tendency, occasional reaching significant level, to conduction slowing and amplitude reduction in the sensory and less often in the motor nerve study. Clinical signs of neuropathy were disclosed in 8.3% of patients, whereas at least one abnormal sensory parameter was evident in 18.3%. Mean SSR latencies in the patients were significantly prolonged. At least one SSR abnormality was shown in 20 (33.3%) patients; six of these had absent SSR from the hand or/and the foot. Polytherapy (vs. monotherapy) and topiramate, but not any other particular drug, seemed to have a negative effect on SSR measurements. The results suggested that despite the insignificant clinical manifestations of neuropathy, an electrophysiological examination was able to demonstrate some subclinical abnormalities of the fast somatic fibers in the peripheral nerves and of the sympathetic sudomotor function in a considerable number of epileptic patients.
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Lithium inhibits function of voltage-dependent sodium channels and catecholamine secretion independent of glycogen synthase kinase-3 in adrenal chromaffin cells. Neuropharmacology 2007; 53:881-9. [DOI: 10.1016/j.neuropharm.2007.08.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 07/31/2007] [Accepted: 08/20/2007] [Indexed: 01/09/2023]
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Bourin M, Prica C. The role of mood stabilisers in the treatment of the depressive facet of bipolar disorders. Neurosci Biobehav Rev 2007; 31:963-75. [PMID: 17462734 DOI: 10.1016/j.neubiorev.2007.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 03/02/2007] [Accepted: 03/06/2007] [Indexed: 11/17/2022]
Abstract
It was previously shown that available mood stabilisers are used to treat bipolar depression. As part of the natural course of illness, patients with bipolar disorder often suffer from episodes of depression more frequently and for longer durations than mania. A major challenge in the treatment of bipolar depression is the tendency for antidepressant medications, particularly tricyclic antidepressants, to precipitate episodes of mania, or to increase cycle frequency or symptom intensity. Thus, exploring the utility of mood stabilisers as monotherapy for bipolar depression is important. The aim of this review it to collate data involving the effects of some mood stabilisers like lithium, carbamazepine, valproate and lamotrigine in depressive aspects of bipolar disorder, but as well using an animal model of depression, to understand their mechanism of action.
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Affiliation(s)
- Michel Bourin
- EA 3256 Neurobiologie de l'anxiété et de la dépression, Faculté de Médecine 1, rue Gaston Veil BP 53508, 44035 Nantes cedex 01, France.
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White HS, Smith MD, Wilcox KS. Mechanisms of action of antiepileptic drugs. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 81:85-110. [PMID: 17433919 DOI: 10.1016/s0074-7742(06)81006-8] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The management of seizures in the patient with epilepsy relies heavily on antiepileptic drug (AED) therapy. Fortunately, for a large percentage of patients, AEDs provide excellent seizure control at doses that do not adversely affect normal function. At the molecular level, the majority of AEDs are thought to modify excitatory and inhibitory neurotransmission through effects on voltage-gated ion channels (e.g., sodium and calcium) and gamma-aminobutyric acid (GABA)(A) receptors, respectively. In addition to these effects, two of the "second-generation" AEDs have been found to limit glutamate-mediated excitatory neurotransmission (i.e., felbamate and topiramate). Not surprisingly, those AEDs with broad spectrum clinical activity are often found to exert an action at more than one molecular target. Emerging evidence suggests that receptor and voltage-gated subunits are modified by chronic seizures. Thus, attempts to understand the relationship between target and effect continue to provide important information about the neuropathology of the epileptic network and to facilitate the development of novel therapies for the treatment of refractory epilepsy.
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Affiliation(s)
- H Steve White
- Anticonvulsant Drug Development Program, Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah 84108, USA
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Li CL, Zhang JH, Yang BF, Jiao JD, Wang L, Wu CF. ANEPIII, a new recombinant neurotoxic polypeptide derived from scorpion peptide, inhibits delayed rectifier, but not A-type potassium currents in rat primary cultured hippocampal and cortical neurons. ACTA ACUST UNITED AC 2006; 133:74-81. [PMID: 16229905 DOI: 10.1016/j.regpep.2005.09.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Accepted: 09/13/2005] [Indexed: 11/26/2022]
Abstract
A new recombinant neurotoxic polypeptide ANEPIII (BmK ANEPIII) derived from Scorpion peptide, which was demonstrated with antineuroexcitation properties in animal models, was examined for its action on K+ currents in primary cultured rat hippocampal and cortical neurons using the patch clamp technique in the whole-cell configuration. The delayed rectifier K+ current (I(k)) was inhibited by externally applied recombinant BmK ANEPIII, while the transient A-current (I(A)) remained virtually unaffected. BmK ANEPIII 3 microM, reduced the delayed rectifier current by 28.2% and 23.6% in cultured rat hippocampal and cortical neurons, respectively. The concentration of half-maximal block was 155.1 nM for hippocampal neurons and 227.2 nM for cortical neurons, respectively. These results suggest that BmK ANEPIII affect K+ currents, which may lead to a reduction in neuronal excitability.
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Affiliation(s)
- Chun-Li Li
- Department of Pharmacology, Shenyang Pharmaceutical University, Shenyang 110016, PR China
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Martín E, Pozo M. Animal models for the development of new neuropharmacological therapeutics in the status epilepticus. Curr Neuropharmacol 2006; 4:33-40. [PMID: 18615135 PMCID: PMC2430677 DOI: 10.2174/157015906775203002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2005] [Revised: 07/06/2005] [Accepted: 09/30/2005] [Indexed: 11/22/2022] Open
Abstract
Status epilepticus (SE) is a major medical emergency associated with significant morbidity and mortality. SE is best defined as a continuous, generalized, convulsive seizure lasting > 5 min, or two or more seizures during which the patient does not return to baseline consciousness. The relative efficacy and safety of different drugs in the treatment of human SE should be determined in a prospective, randomized, blinded study. However, complementary animal models of SE are required to answer important questions concerning the treatment of SE because of the obvious difficulties of setting up such studies in clinical emergency conditions. This review offers an overview of the implementation and characteristics of some of the most prevalent animal models of SE currently in use. A description is also provide about how animal models of SE may facilitate the use of neurobiological techniques to successfully address critical questions in the drug treatment of SE. In particular, the experience with recently introduced drugs such as intravenous valproate will be addressed. Finally, the importance of some animal models and pharmacological approaches is explained and we discuss their impact in the development of therapeutic strategies to improve pharmacological treatment for SE is discussed.
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Affiliation(s)
- Ed Martín
- Unidad Asociada Neurodeath, UCLM-CSIC, Departamento de Ciencias Médicas, Universidad de Castilla-La Mancha, Avda. de Almansa s/n, 02006, Albacete, Spain.
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Martín ED, Pozo MA. Valproate reduced synaptic activity increase induced by 4-aminopyridine at the hippocampal CA3-CA1 synapse. Epilepsia 2004; 45:436-40. [PMID: 15101824 DOI: 10.1111/j.0013-9580.2004.58303.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE We investigated the effects of valproate (VPA) on excitatory synaptic transmission changes induced by 4-aminopyridine (4-AP) to determine whether the antiepileptic effects shown by VPA can be ascribed to a modulation of spontaneous excitatory postsynaptic currents (sEPSCs) in the CA3-CA1 synapse. METHODS Rat hippocampal slices were prepared and maintained in vitro with standard methods. Whole-cell current and voltage-clamp recordings were obtained from CA1 pyramidal neurons by using the "blind" patch-clamp technique in an immersion recording chamber. Increase in the spontaneous excitatory synaptic activity was induced by addition of 4-AP to the medium. RESULTS Perfusion with VPA significantly counteracted the increase of frequency and amplitude of the sEPSCs induced by application of 4-AP and suppressed the epileptiform activity. CONCLUSIONS We conclude that VPA decreases the 4-AP-induced enhancement of excitatory synaptic activity at the CA3-CA1 synapse, and that this reduction of excitation input to CA1 contributes to the anticonvulsant effects of VPA.
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Affiliation(s)
- Eduardo D Martín
- Brain Mapping Unit, Pluridisciplinary Institute, UCM, Madrid, Spain.
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Martín ED, Pozo MA. Valproate reduced excitatory postsynaptic currents in hippocampal CA1 pyramidal neurons. Neuropharmacology 2004; 46:555-61. [PMID: 14975679 DOI: 10.1016/j.neuropharm.2003.10.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2003] [Revised: 07/24/2003] [Accepted: 09/11/2003] [Indexed: 12/21/2022]
Abstract
Valproate (VPA) is one of the most widely used antiepileptic drugs, and it is also increasingly used for the treatment of neuropsychological disorders and neuropathic pain, as well as migraine prophylaxis. However, the underlying cellular mechanisms of VPA on the synaptic physiology remain unclear. We investigated the effects of VPA on synaptic transmission using the in vitro rat hippocampal slice technique and whole-cell patch clamp recordings from CA1 pyramidal neurons. Perfusion with VPA, at therapeutically attainable concentrations, decreased the amplitude of excitatory postsynaptic currents (EPSCs) evoked by Schaffer collateral stimulation, without modifying inhibitory postsynaptic currents (IPSCs). Furthermore, VPA induced a significant reduction of the non-NMDA EPSC (non-NMDA(EPSC)) component, without modifying the NMDA EPSC (NMDA(EPSC)) component. Paired pulse facilitation and EPSC variance were not significantly affected by VPA, indicating that VPA did not decrease transmitter release probability, which suggests a postsynaptic mechanism of action. We therefore conclude that VPA decreases excitatory synaptic activity through the modulation of postsynaptic non-NMDA receptors, without modifying synaptic inhibition, and that this reduction of excitation is, at least in part, responsible for the effects of VPA.
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Affiliation(s)
- Eduardo D Martín
- Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Avda Almansa s/n, 02071 Albacete, Spain.
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Zhang MM, Xiao C, Yu K, Ruan DY. Effects of sodium valproate on synaptic plasticity in the CA1 region of rat hippocampus. Food Chem Toxicol 2003; 41:1617-23. [PMID: 12963015 DOI: 10.1016/s0278-6915(03)00195-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Sodium valproate (VPA) is currently one of the major anticonvulsant drug in clinical use and has a wide spectrum of antiepileptic activity. Previous studies have reported that VPA impairs long-term potentiation (LTP). In the present study, we used two forms of synaptic plasticity, LTP and long-term depression (LTD) of field excitatory postsynaptic potential (fEPSP) to investigate the effects of VPA on synaptic plasticity in rat hippocampal slices. Paired-pulse facilitation (PPF) and field EPSP were recorded in the CA1 area of hippocampal slices exposed to VPA. The results showed that: (1) three different concentrations of VPA (0.6, 1 and 5 mM) all induced a significant impairment of PPF at 20-150 ms inter-pulse intervals (IPI) (P<0.05). (2) acute VPA exposure (0.6 mM) inhibited the induction of LTP (Control: 171 +/- 20%, n=8; VPA-exposed: 117 +/- 16%, n=9, P<0.01) and LTD (Control: 86 +/- 13%, n=8; VPA-exposed: 98 +/- 8%, n=10, P<0.01); and (3) GABA(A) receptor antagonist picrotoxin (PTX) (10 microM) reversed VPA-induced deficits of LTP (VPA-exposed: 117 +/- 16%, n=9; VPA-exposed+PTX: 153 +/- 20%, n=8, P<0.01). However, PTX had no significant effect on impairment of LTD (VPA-exposed: 98 +/- 8%, n=10; VPA-exposed+PTX: 97 +/- 3%, n=8, P>0.05). These results suggested that VPA impaired LTP and LTD. Furthermore, VPA-induced impairment of LTP could be correlated with the enhancement of inhibitory neurotransmission mediated by gamma-aminobutyric acid (GABA) receptor.
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Affiliation(s)
- Min-Min Zhang
- School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230027, PR China
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Zhang MM, Yu K, Xiao C, Ruan DY. The influence of developmental periods of sodium valproate exposure on synaptic plasticity in the CA1 region of rat hippocampus. Neurosci Lett 2003; 351:165-8. [PMID: 14623132 DOI: 10.1016/j.neulet.2003.08.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effects of chronic sodium valproate (VPA) exposure during different developmental periods on synaptic plasticity were studied in the hippocampal CA1 area. Rats were exposed to VPA (300 mg/kg per day, intraperitoneal) over different developmental intervals: (1). prenatal exposure (PR group); (2). from parturition to weaning (PW group); (3). from pregnancy day 1 to weaning (PRW group). At postnatal day 22-28, field excitatory postsynaptic potentials were recorded in the CA1 area of hippocampal slices. We found that VPA exposure in the PR and PRW groups significantly impaired long-term potentiation (LTP), long-term depression (LTD) and paired-pulse facilitation (PPF). However, exposure during lactation (PW group) only impaired LTP and had no significant effect on LTD and PPF. These results suggested that VPA exposure during lactation had the least deficits on synaptic plasticity, while VPA exposure in the PR and PRW groups seriously impaired synaptic plasticity and should be avoided.
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Affiliation(s)
- Min-Min Zhang
- School of Life Science, University of Science and Technology of China, Hefei, Anhui, 230027, PR China
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45
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Madeja M, Margineanu DG, Gorji A, Siep E, Boerrigter P, Klitgaard H, Speckmann EJ. Reduction of voltage-operated potassium currents by levetiracetam: a novel antiepileptic mechanism of action? Neuropharmacology 2003; 45:661-71. [PMID: 12941379 DOI: 10.1016/s0028-3908(03)00248-x] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Levetiracetam (ucb L059; Keppra) is a novel antiepileptic drug. Its effects on action potential generation and voltage-operated potassium currents were studied in acutely isolated hippocampal CA1 neurones from rat and guinea pig, using the patch-clamp technique in the whole-cell configuration. (i) Levetiracetam reduced repetitive action potential generation and affected the single action potential. Levetiracetam, 100 microM, decreased the total number of action potentials and reduced the total depolarisation area of repetitive action potentials by 21%. Furthermore, levetiracetam increased the duration of the first action potential slightly, prolonged that of the second action potential by 13% and decreased the slope of rise by 23%. (ii) Levetiracetam decreased the voltage-operated potassium current. Without effect on sodium and A-type potassium currents, levetiracetam, 100 microM, reduced the delayed rectifier current by 26%. The concentration of half-maximal block was 47 microM for guinea pig and 6 microM for rat neurones. Thus, the reduction of repetitive action potential generation by levetiracetam can be attributed, unexpectedly, to a moderate reduction of the delayed rectifier potassium current, as supported by a simulation of action potential generation. This suggests that a reduction of potassium currents may contribute to the antiepileptic effect(s) of levetiracetam.
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Affiliation(s)
- Michael Madeja
- Institute for Physiology, University Münster, Robert-Koch-Str. 27A, 48149 Münster, Germany.
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Abstract
Animal experiments, and particularly functional investigations on human chronically epileptic tissue as well as genetic studies in epilepsy patients and their families strongly suggest that some forms of epilepsy may share a pathogenetic mechanism: an alteration of voltage-gated sodium channels. This review summarizes recent data on changes of sodium channel expression, molecular structure and function associated with epilepsy, as well as on the interaction of new and established antiepileptic drugs with sodium currents. Although it remains to be determined precisely how and to what extent altered sodium-channel functions play a role in different epilepsy syndromes, future promising therapy approaches may include drugs modulating sodium currents, and particularly substances changing their inactivation characteristics.
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Affiliation(s)
- Rüdiger Köhling
- Institut für Physiologie, Westfälische Wilhelms-Universität Münster, Münster, Germany.
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Gebhardt C, Breustedt JM, Nöldner M, Chatterjee SS, Heinemann U. The antiepileptic drug losigamone decreases the persistent Na+ current in rat hippocampal neurons. Brain Res 2001; 920:27-31. [PMID: 11716808 DOI: 10.1016/s0006-8993(01)02863-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The tetronic acid derivative losigamone is a new anticonvulsant drug with a mechanism of action that was previously unknown. The drug decreases the frequency of spontaneous action potentials and suppresses repetitive firing of neurons. Here we tested the hypothesis that losigamone suppresses the persistent Na+ current (I(NaP)) in hippocampal neurons of rat brain slices and in cultured hippocampal neurons. Whole-cell voltage clamp recordings from neurons of juvenile rats (P15-P25) were performed with pipettes filled with Cs-gluconate or CsF. After pharmacological block of K+ and Ca2+ currents I(NaP) was revealed by applying slow depolarizing voltage ramps from -70 to 0 mV. Losigamone (100-200 microM) was dissolved in DMSO (0.1%) and was applied by bath application or local pressure application. Losigamone induced a decrease in amplitude of I(NaP) at depolarized membrane potentials which was reversible in cultured neurons. When tetrodotoxin (TTX) was added to the bath, I(NaP) was blocked and only a residual non-specific outward cation current (I(cat)) remained. Losigamone had no obvious effect on responses to voltage ramps under these conditions. Thus, losigamone did not affect I(cat) or induce any additional currents. The data suggest that losigamone decreases neuronal excitability via a decrease in I(NaP).
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Affiliation(s)
- C Gebhardt
- Johannes-Mueller-Institute of Physiology, Charité, Humboldt-University, Tucholskystr. 2, 10117, Berlin, Germany.
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Abstract
In the past decade, nine new drugs have been licensed for the treatment of epilepsy. With limited clinical experience of these agents, the mechanisms of action of antiepileptic drugs may be an important criterion in the selection of the most suitable treatment regimens for individual patients. At the cellular level, three basic mechanisms are recognised: modulation of voltage-dependent ion channels, enhancement of inhibitory neurotransmission, and attenuation of excitatory transmission. In this review, we will attempt to introduce the concepts of ion channel and neurotransmitter modulation and, thereafter, group currently used antiepileptic drugs according to their principal mechanisms of action.
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Affiliation(s)
- P Kwan
- Epilepsy Unit, University Department of Medicine and Therapeutics, Western Infirmary, Glasgow G11 6NT, Scotland, UK
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Abstract
Valproate is currently one of the major antiepileptic drugs with efficacy for the treatment of both generalized and partial seizures in adults and children. Furthermore, the drug is increasingly used for therapy of bipolar and schizoaffective disorders, neuropathic pain and for prophylactic treatment of migraine. These various therapeutic effects are reflected in preclinical models, including a variety of animal models of seizures or epilepsy. The incidence of toxicity associated with the clinical use of valproate is low, but two rare toxic effects, idiosyncratic fatal hepatotoxicity and teratogenicity, necessitate precautions in risk patient populations. Studies from animal models on structure-relationships indicate that the mechanisms leading to hepatotoxicity and teratogenicity are distinct and also differ from the mechanisms of anticonvulsant action of valproate. Because of its wide spectrum of anticonvulsant activity against different seizure types, it has repeatedly been suggested that valproate acts through a combination of several mechanisms. As shown in this review, there is substantial evidence that valproate increases GABA synthesis and release and thereby potentiates GABAergic functions in some specific brain regions, such as substantia nigra, thought to be involved in the control of seizure generation and propagation. Furthermore, valproate seems to reduce the release of the epileptogenic amino acid gamma-hydroxybutyric acid and to attenuate neuronal excitation induced by NMDA-type glutamate receptors. In addition to effects on amino acidergic neurotransmission, valproate exerts direct effects on excitable membranes, although the importance of this action is equivocal. Microdialysis data suggest that valproate alters dopaminergic and serotonergic functions. Valproate is metabolized to several pharmacologically active metabolites, but because of the low plasma and brain concentrations of these compounds it is not likely that they contribute significantly to the anticonvulsant and toxic effects of treatment with the parent drug. By the experimental observations summarized in this review, most clinical effects of valproate can be explained, although much remains to be learned at a number of different levels of valproate's mechanisms of action.
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Affiliation(s)
- W Löscher
- Department of Pharmacology, Toxicology and Pharmacy, School of Veterinary Medicine, Hannover, Germany.
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Taverna S, Mantegazza M, Franceschetti S, Avanzini G. Valproate selectively reduces the persistent fraction of Na+ current in neocortical neurons. Epilepsy Res 1998; 32:304-8. [PMID: 9761329 DOI: 10.1016/s0920-1211(98)00060-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The effect of valproate (VPA) on Na+ currents (INa), was studied by means of voltage clamp recordings using whole-cell patch clamp configuration in 21 acutely dissociated neocortical neurons. Concentrations of VPA up to 200 microM failed to induce any detectable decrease in fast INa (I(Naf)), but the persistent fraction (I(NaP)) was significantly reduced by low VPA concentrations (10-30 microM), corresponding to the lower values of the 'therapeutic' range in epileptic patients. Since it is known that I(NaP) critically regulates the firing properties of pyramidal neurons, it is suggested that the anticonvulsant effectiveness of VPA is mainly due to its effect on I(NaP).
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Affiliation(s)
- S Taverna
- Istituto Nazionale Neurologico C. Besta, Laboratorio di Neurofisiologia Sperimentale, Milano, Italy
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