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Harahap Y, Ng L, Sunarsih S. Pharmacokinetic profile of phenytoin in dried blood spot with high-performance liquid chromatography-photodiode array. Front Pharmacol 2024; 15:1326996. [PMID: 38989139 PMCID: PMC11233438 DOI: 10.3389/fphar.2024.1326996] [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: 11/12/2023] [Accepted: 06/04/2024] [Indexed: 07/12/2024] Open
Abstract
Phenytoin is a first-line antiepileptic drug with narrow therapeutic range and follows non-linear pharmacokinetics. Pharmacokinetics of phenytoin have been studied in plasma matrix before, however, there were several disadvantages. This study aimed to obtain partial validation data of the analytical method and the pharmacokinetic profile of phenytoin in Dried Blood Spot (DBS) of six healthy subjects. DBS has the advantage of only requiring small sample volumes and could be transported more efficiently. Phenytoin along with carbamazepine as the chosen internal standard was analyzed with a reversed-phase high performance-liquid chromatography system and a photodiode array detector at 205 nm. The results of partial validation, which evaluated the linearity, within-run accuracy, and precision, were within the criteria acceptance range. The pharmacokinetic profile showed that average AUC0-t was 83.81 ± 37.32 μg.h/mL and AUC0-∞ was 83.65 ± 38.89 μg.h/mL with an average ratio of 93%. Previous study quantifying phenytoin in the plasma matrix found the average AUC0-t was 39.41 ± 8.57 µg.h/mL and AUC0-∞ was 42.94 ± 9.55 µg.h/mL. Despite the difference between parameters of phenytoin analyzed in DBS and plasma matrices, the pharmacokinetic profiles obtained from both matrices were similar indicated by comparable concentration-time curves, thus, proving that DBS matrix can be used interchangeably with the plasma matrix as a more comfortable and effective alternative to phenytoin quantification in blood.
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Affiliation(s)
- Yahdiana Harahap
- Bioavailability/Bioequivalence Laboratory, Faculty of Pharmacy, Universitas Indonesia, Depok, Indonesia
- Faculty of Military Pharmacy, Republic of Indonesia Defense University, Bogor, Indonesia
| | - Limeylia Ng
- Bioavailability/Bioequivalence Laboratory, Faculty of Pharmacy, Universitas Indonesia, Depok, Indonesia
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Chowdhury R, Bhuia MS, Al Hasan MS, Ansari SA, Ansari IA, Gurgel APAD, Coutinho HDM, Islam MT. Anticonvulsant effect of (±) citronellal possibly through the GABAergic and voltage-gated sodium channel receptor interaction pathways: In vivo and in silico studies. Neurochem Int 2024; 175:105704. [PMID: 38395152 DOI: 10.1016/j.neuint.2024.105704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/07/2024] [Accepted: 02/21/2024] [Indexed: 02/25/2024]
Abstract
This study aimed to investigate the anticonvulsant effects of citronellal (CIT) and possible underlying mechanisms through an isoniazid (INH)-induced seizure (convulsion) via in vivo and in silico studies. For this, convulsions were induced by the oral administration of INH (300 mg/kg) to the mice. The animals were treated orally with different doses of CIT (50, 100, and 200 mg/kg). Vehicle served as a negative control (NC), while diazepam (DZP) (2 mg/kg) and carbamazepine (CAR) (80 mg/kg) were provided (p.o.) as positive controls (PC). A combination therapy of CIT (middle dose) with DZP and CAR was also given to two separate groups of animals to estimate the synergistic or antagonistic effects. Molecular docking and visualization of ligand-receptor interactions are also estimated through different computational tools. The results of the in vivo study showed that CIT dose-dependently significantly (p < 0.05) exhibited a higher onset of seizures while reducing the frequency and duration of seizures in mice compared to the NC group. Besides these, in combination therapy, CIT significantly antagonized the activity of CAR and DZP, leading to a reduction in the onset of seizures and an increase in their frequency and duration compared to treatment with CAR and DZP alone. Additionally, molecular docking revealed that the CIT exhibited a moderate binding affinity (-5.8 kcal/mol) towards the GABAA receptor and a relative binding affinity (-5.3 kcal/mol) towards the voltage-gated sodium channel receptor by forming several bonds. In conclusion, CIT showed moderate anticonvulsant activity in INH-induced convulsion animals, possibly by enhancing GABAA receptor activity and inhibiting the voltage-gated sodium channel receptor.
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Affiliation(s)
- Raihan Chowdhury
- Department of Pharmacy, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, 8100, Bangladesh
| | - Md Shimul Bhuia
- Department of Pharmacy, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, 8100, Bangladesh; Bioluster Research Center, Gopalganj, 8100, Dhaka, Bangladesh
| | - Md Sakib Al Hasan
- Department of Pharmacy, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, 8100, Bangladesh; Bioluster Research Center, Gopalganj, 8100, Dhaka, Bangladesh
| | - Siddique Akber Ansari
- Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Irfan Aamer Ansari
- Department of Drug Science and Technology, University of Turin, Turin, 10124, Italy
| | | | - Henrique Douglas Melo Coutinho
- Department of Biological Chemistry, Laboratory of Microbiology and Molecular Biology, Regional University of Cariri, Crato CE, 63105-000, Brazil CE, 63105-000, Brazil.
| | - Muhammad Torequl Islam
- Department of Pharmacy, Bangabandhu Sheikh Mujibur Rahman Science and Technology University, Gopalganj, 8100, Bangladesh.
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Llanos MA, Enrique N, Esteban-López V, Scioli-Montoto S, Sánchez-Benito D, Ruiz ME, Milesi V, López DE, Talevi A, Martín P, Gavernet L. A Combined Ligand- and Structure-Based Virtual Screening To Identify Novel NaV1.2 Blockers: In Vitro Patch Clamp Validation and In Vivo Anticonvulsant Activity. J Chem Inf Model 2023; 63:7083-7096. [PMID: 37917937 DOI: 10.1021/acs.jcim.3c00645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Epilepsy is a neurological disorder characterized by recurrent seizures that arise from abnormal electrical activity in the brain. Voltage-gated sodium channels (NaVs), responsible for the initiation and propagation of action potentials in neurons, play a critical role in the pathogenesis of epilepsy. This study sought to discover potential anticonvulsant compounds that interact with NaVs, specifically, the brain subtype hNaV1.2. A ligand-based QSAR model and a docking model were constructed, validated, and applied in a parallel virtual screening over the DrugBank database. Montelukast, Novobiocin, and Cinnarizine were selected for in vitro testing, using the patch-clamp technique, and all of them proved to inhibit hNaV1.2 channels heterologously expressed in HEK293 cells. Two hits were evaluated in the GASH/Sal model of audiogenic seizures and demonstrated promising activity, reducing the severity of sound-induced seizures at the doses tested. The combination of ligand- and structure-based models presents a valuable approach for identifying potential NaV inhibitors. These findings may provide a basis for further research into the development of new antiseizure drugs for the treatment of epilepsy.
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Affiliation(s)
- Manuel A Llanos
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - Nicolás Enrique
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Vega Esteban-López
- Institute for Neuroscience of Castilla y León (INCyL), University of Salamanca, Salamanca 37008, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca 37007, Spain
| | - Sebastian Scioli-Montoto
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - David Sánchez-Benito
- Institute for Neuroscience of Castilla y León (INCyL), University of Salamanca, Salamanca 37008, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca 37007, Spain
| | - María E Ruiz
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - Veronica Milesi
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Dolores E López
- Institute for Neuroscience of Castilla y León (INCyL), University of Salamanca, Salamanca 37008, Spain
- Institute for Biomedical Research of Salamanca (IBSAL), Salamanca 37007, Spain
| | - Alan Talevi
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
| | - Pedro Martín
- Facultad de Ciencias Exactas, Departamento de Ciencias Biológicas, Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, La Plata B1900BJW, Buenos Aires, Argentina
| | - Luciana Gavernet
- Laboratory of Bioactive Compounds Research and Development (LIDeB), Department of Biological Sciences, Faculty of Exact Sciences, National University of La Plata (UNLP), La Plata B1900ADU, Argentina
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Kocot-Kępska M, Pawlik K, Ciapała K, Makuch W, Zajączkowska R, Dobrogowski J, Przeklasa-Muszyńska A, Mika J. Phenytoin Decreases Pain-like Behaviors and Improves Opioid Analgesia in a Rat Model of Neuropathic Pain. Brain Sci 2023; 13:858. [PMID: 37371338 DOI: 10.3390/brainsci13060858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 05/18/2023] [Accepted: 05/24/2023] [Indexed: 06/29/2023] Open
Abstract
Neuropathic pain remains a clinical challenge due to its complex and not yet fully understood pathomechanism, which result in limited analgesic effectiveness of the management offered, particularly for patients with acute, refractory neuropathic pain states. In addition to the introduction of several modern therapeutic approaches, such as neuromodulation or novel anti-neuropathic drugs, significant efforts have been made in the repurposing of well-known substances such as phenytoin. Although its main mechanism of action occurs at sodium channels in excitable and non-excitable cells and is well documented, how the drug affects the disturbed neuropathic interactions at the spinal cord level and how it influences morphine-induced analgesia have not been clarified, both being crucial from a clinical perspective. We demonstrated that single and repeated systemic administrations of phenytoin decreased tactile and thermal hypersensitivity in an animal model of neuropathic pain. Importantly, we observed an increase in the antinociceptive effect on thermal stimuli with repeated administrations of phenytoin. This is the first study to report that phenytoin improves morphine-induced antinociceptive effects and influences microglia/macrophage activity at the spinal cord and dorsal root ganglion levels in a neuropathic pain model. Our findings support the hypothesis that phenytoin may represent an effective strategy for neuropathic pain management in clinical practice, particularly when combination with opioids is needed.
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Affiliation(s)
- Magdalena Kocot-Kępska
- Department of Pain Research and Treatment, Jagiellonian University Medical College, 31-501 Krakow, Poland
| | - Katarzyna Pawlik
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
| | - Katarzyna Ciapała
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
| | - Wioletta Makuch
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
| | - Renata Zajączkowska
- Department of Interdisciplinary Intensive Care, Jagiellonian University Medical College, 30-688 Krakow, Poland
| | - Jan Dobrogowski
- Department of Pain Research and Treatment, Jagiellonian University Medical College, 31-501 Krakow, Poland
| | - Anna Przeklasa-Muszyńska
- Department of Pain Research and Treatment, Jagiellonian University Medical College, 31-501 Krakow, Poland
| | - Joanna Mika
- Department of Pain Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, 31-343 Krakow, Poland
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Colombo S, Reddy HP, Petri S, Williams DJ, Shalomov B, Dhindsa RS, Gelfman S, Krizay D, Bera AK, Yang M, Peng Y, Makinson CD, Boland MJ, Frankel WN, Goldstein DB, Dascal N. Epilepsy in a mouse model of GNB1 encephalopathy arises from altered potassium (GIRK) channel signaling and is alleviated by a GIRK inhibitor. Front Cell Neurosci 2023; 17:1175895. [PMID: 37275776 PMCID: PMC10232839 DOI: 10.3389/fncel.2023.1175895] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 04/12/2023] [Indexed: 06/07/2023] Open
Abstract
De novo mutations in GNB1, encoding the Gβ1 subunit of G proteins, cause a neurodevelopmental disorder with global developmental delay and epilepsy, GNB1 encephalopathy. Here, we show that mice carrying a pathogenic mutation, K78R, recapitulate aspects of the disorder, including developmental delay and generalized seizures. Cultured mutant cortical neurons also display aberrant bursting activity on multi-electrode arrays. Strikingly, the antiepileptic drug ethosuximide (ETX) restores normal neuronal network behavior in vitro and suppresses spike-and-wave discharges (SWD) in vivo. ETX is a known blocker of T-type voltage-gated Ca2+ channels and G protein-coupled potassium (GIRK) channels. Accordingly, we present evidence that K78R results in a gain-of-function (GoF) effect by increasing the activation of GIRK channels in cultured neurons and a heterologous model (Xenopus oocytes)-an effect we show can be potently inhibited by ETX. This work implicates a GoF mechanism for GIRK channels in epilepsy, identifies a new mechanism of action for ETX in preventing seizures, and establishes this mouse model as a pre-clinical tool for translational research with predicative value for GNB1 encephalopathy.
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Affiliation(s)
- Sophie Colombo
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Haritha P. Reddy
- Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, India
| | - Sabrina Petri
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Damian J. Williams
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Boris Shalomov
- Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ryan S. Dhindsa
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Sahar Gelfman
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Daniel Krizay
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Amal K. Bera
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, India
| | - Mu Yang
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
- Mouse NeuroBehavior Core Facility, Columbia University Irving Medical Center, New York, NY, United States
| | - Yueqing Peng
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, United States
| | - Christopher D. Makinson
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
- Department of Neuroscience, Columbia University, New York, NY, United States
| | - Michael J. Boland
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - Wayne N. Frankel
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, United States
| | - David B. Goldstein
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, NY, United States
| | - Nathan Dascal
- Department of Physiology and Pharmacology, School of Medicine, Tel Aviv University, Tel Aviv, Israel
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Song J, Jiang M, Jin Y, Li H, Li Y, Liu Y, Yu H, Huang X. Phytol from Faeces Bombycis alleviated migraine pain by inhibiting Nav1.7 sodium channels. JOURNAL OF ETHNOPHARMACOLOGY 2023; 306:116161. [PMID: 36646158 DOI: 10.1016/j.jep.2023.116161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 12/11/2022] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Faeces Bombycis (silkworm excrement, called Cansha in Chinese), is the dried faeces of the larvae of silkworm. According to the theories of traditional Chinese medicine recorded in "Compendium of Materia Medica", Faeces Bombycis has often been prescribed in traditional Chinese medicine for the treatment of recurrent headache, rheumatalgia, rubella and itching et al. However, the bioactive components and their exact mechanisms underlying the pain-relieving effects remain to be revealed. AIM OF THE STUDY The present study aimed to evaluate the analgesic effect of Faeces Bombycis extract (FBE) on migraine, explore the main active constituents and investigate the pharmacological mechanisms for its pain relief. MATERIALS AND METHODS The bioactivity of different extracts from Faeces Bombycis was tracked by the nitroglycerin (NTG)-induced migraine model on rats and identified by NMR spectroscopic data. Whole-cell patch clamp technique, an electrophysiological method, was used to screen the potential targets and study the mechanism of action for the bioactive compound. The following targets have been screened and studied, including Nav1.7 sodium channels, Nav1.8 sodium channels, TRPV1 channels and TRPA1 channels. The trigeminal ganglion neurons were further used to study the effects of the identified compound on neuronal excitability. RESULTS By testing the bioactivity of the different extracts proceedingly, fraction petroleum ether showed higher anti-migraine activity. Through further step-by-step isolations, 7 compounds were isolated. Among them, phytol was identified with the highest yield and displayed a potent anti-migraine effect. By screening the potential ion channel targets for migraine, phytol was found to preferentially block the inactivated state of Nav1.7 sodium channels with half-inhibition concentration 0.32 ± 0.05 μM. Thus, the effects of phytol on the biophysical properties of Nav1.7 sodium channels were further characterized. Phytol induced a hyperpolarizing shift of voltage-dependent inactivation and slowed the recovery from inactivation. The affinity of phytol became weaker in the inactivation-deficient Nav1.7 channels (Nav1.7-WCW). And such an effect was independent on the local anesthetic site (Nav1.7 F1737A). Consistent with the data from recombinant channels, the compound also displayed state-dependent inhibition on neuronal sodium channels and further decreased the neuronal excitability in trigeminal ganglion neurons. Moreover, besides Nav1.7 channel, phytol also antagonized the activation of TRPV1 and TRPA1 channels at micromolar concentrations with a weaker affinity. CONCLUSION Our results demonstrated that phytol is the major anti-migraine ingredient of Faeces Bombycis and alleviates migraine behaviors by acting on Nav1.7 sodium channels in the trigeminal ganglion neurons. This study provided evidences for the therapeutic application of Faeces Bombycis and phytol on migraine disease.
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Affiliation(s)
- Jianan Song
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming, 650504, China; State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China; Department of Neurobiology, Harbin Medical University, Harbin, 150086, China.
| | - Mengyuan Jiang
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming, 650504, China.
| | - Yuchen Jin
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China.
| | - Hongrui Li
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming, 650504, China.
| | - Yanhong Li
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming, 650504, China.
| | - Yumei Liu
- Department of Neurobiology, Harbin Medical University, Harbin, 150086, China.
| | - Haibo Yu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China.
| | - Xiangzhong Huang
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming, 650504, China.
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Bayraktar E, Liu Y, Sonnenberg L, Hedrich UBS, Sara Y, Eltokhi A, Lyu H, Lerche H, Wuttke TV, Lauxmann S. In vitro effects of eslicarbazepine (S-licarbazepine) as a potential precision therapy on SCN8A variants causing neuropsychiatric disorders. Br J Pharmacol 2023; 180:1038-1055. [PMID: 36321697 DOI: 10.1111/bph.15981] [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: 08/20/2021] [Revised: 10/06/2022] [Accepted: 10/07/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Variants in SCN8A, the NaV 1.6 channel's coding gene, are characterized by a variety of symptoms, including intractable epileptic seizures, psychomotor delay, progressive cognitive decline, autistic features, ataxia or dystonia. Standard anticonvulsant treatment has a limited impact on the course of disease. EXPERIMENTAL APPROACH We investigated the therapeutic potential of eslicarbazepine (S-licarbazepine; S-lic), an enhancer of slow inactivation of voltage gated sodium channels, on two variants with biophysical and neuronal gain-of-function (G1475R and M1760I) and one variant with biophysical gain-of-function but neuronal loss-of-function (A1622D) in neuroblastoma cells and in murine primary hippocampal neuron cultures. These three variants cover the broad spectrum of NaV 1.6-associated disease and are linked to representative phenotypes of mild to moderate epilepsy (G1475R), developmental and epileptic encephalopathy (M1760I) and intellectual disability without epilepsy (A1622D). KEY RESULTS Similar to known effects on NaV 1.6 wildtype channels, S-lic predominantly enhances slow inactivation on all tested variants, irrespective of their particular biophysical mechanisms. Beyond that, S-lic exhibits variant-specific effects including a partial reversal of pathologically slowed fast inactivation dynamics (A1622D and M1760I) and a trend to reduce enhanced persistent Na+ current by A1622D variant channels. Furthermore, our data in primary transfected neurons reveal that not only variant-associated hyperexcitability (M1760I and G1475R) but also hypoexcitability (A1622D) can be modulated by S-lic. CONCLUSIONS AND IMPLICATIONS S-lic has not only substance-specific effects but also variant-specific effects. Personalized treatment regimens optimized to achieve such variant-specific pharmacological modulation may help to reduce adverse side effects and improve the overall therapeutic outcome of SCN8A-related disease.
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Affiliation(s)
- Erva Bayraktar
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Medical Pharmacology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Yuanyuan Liu
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Lukas Sonnenberg
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurobiology, University of Tübingen, Tübingen, Germany
| | - Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Yildirim Sara
- Department of Medical Pharmacology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - Ahmed Eltokhi
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - Hang Lyu
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thomas V Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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8
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Costa B, Vale N. Understanding Lamotrigine's Role in the CNS and Possible Future Evolution. Int J Mol Sci 2023; 24:ijms24076050. [PMID: 37047022 PMCID: PMC10093959 DOI: 10.3390/ijms24076050] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/20/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023] Open
Abstract
The anti-epileptic drug lamotrigine (LTG) has been widely used to treat various neurological disorders, including epilepsy and bipolar disorder. However, its precise mechanism of action in the central nervous system (CNS) still needs to be determined. Recent studies have highlighted the involvement of LTG in modulating the activity of voltage-gated ion channels, particularly those related to the inhibition of neuronal excitability. Additionally, LTG has been found to have neuroprotective effects, potentially through the inhibition of glutamate release and the enhancement of GABAergic neurotransmission. LTG's unique mechanism of action compared to other anti-epileptic drugs has led to the investigation of its use in treating other CNS disorders, such as neuropathic pain, PTSD, and major depressive disorder. Furthermore, the drug has been combined with other anti-epileptic drugs and mood stabilizers, which may enhance its therapeutic effects. In conclusion, LTG's potential to modulate multiple neurotransmitters and ion channels in the CNS makes it a promising drug for treating various neurological disorders. As our understanding of its mechanism of action in the CNS continues to evolve, the potential for the drug to be used in new indications will also be explored.
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Affiliation(s)
- Bárbara Costa
- OncoPharma Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Doutor Plácido da Costa, s/n, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- Department of Community Medicine, Information and Health Decision Sciences (MEDCIDS), Faculty of Medicine, University of Porto, Rua Doutor Plácido da Costa, s/n, 4200-450 Porto, Portugal
| | - Nuno Vale
- OncoPharma Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Doutor Plácido da Costa, s/n, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- Department of Community Medicine, Information and Health Decision Sciences (MEDCIDS), Faculty of Medicine, University of Porto, Rua Doutor Plácido da Costa, s/n, 4200-450 Porto, Portugal
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9
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Liang L, Bai X, Hua Z. Enhancement of the immobilization on microalgae protective effects and carbamazepine removal by Chlorella vulgaris. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:79567-79578. [PMID: 35715671 DOI: 10.1007/s11356-022-21418-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
Carbamazepine (CBZ) has drawn extensive attention due to their environmental threats. In this study, polyvinyl alcohol-sodium alginate polymers to immobilize Chlorella vulgaris (FACHB-8) were used to investigate whether immobilization can facilitate microalgae to alleviate the CBZ stress and enhance CBZ removal. The results showed that after immobilized treatment, the biomass of microalgae increased by approximately 20%, the maximum level of malondialdehyde content decreased from 28 to 13 μmol/g, and the photosynthetic capacity of FV/FM recovered to 90% of the control group. The CBZ removal rate increased from 67 to 84% by immobilization at a CBZ concentration of 80 mg·L-1. The results indicated that immobilization technology can effectively protect microalgae from CBZ toxicity and improve the removal of CBZ, especially at high concentrations (> 50 mg/L). Biodegradation was the dominant pathway for microalgae to remove carbamazepine. This study added the understanding of the microalgae responses under immobilization and the interactions between immobilized microalgae and CBZ removal, thereby providing a novel insight into microalgae technology in high concentration wastewater treatments.
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Affiliation(s)
- Lu Liang
- College of Environment, Hohai University, Xikang road 1#, Gulou District, Nanjing, 210098, China
| | - Xue Bai
- College of Environment, Hohai University, Xikang road 1#, Gulou District, Nanjing, 210098, China
| | - Zulin Hua
- College of Environment, Hohai University, Xikang road 1#, Gulou District, Nanjing, 210098, China.
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10
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Omer H, Omer MH, Alyousef AR, Alzammam AM, Ahmad O, Alanazi HA. Unmasking of Brugada syndrome by lamotrigine in a patient with pre-existing epilepsy: A case report with review of the literature. Front Cardiovasc Med 2022; 9:1005952. [PMID: 36407465 PMCID: PMC9673589 DOI: 10.3389/fcvm.2022.1005952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 10/10/2022] [Indexed: 11/26/2022] Open
Abstract
Brugada syndrome is an inherited cardiac channelopathy arising from mutations in voltage-gated cardiac sodium channels. Idiopathic epilepsy portrays a coalescent underlying pathophysiological mechanism pertaining to the premature excitation of neuronal voltage-gated ion channels resulting in the disruption of presynaptic neurons and the unregulated release of excitatory neurotransmitters. The coexistence of epilepsy and Brugada syndrome may be explained by mutations in voltage-gated ion channels, which are coexpressed in cardiac and neural tissue. Moreover, the incidence of sudden unexpected death in epilepsy has been associated with malignant cardiac arrhythmias in the presence of mutations in voltage-gated ion channels. Lamotrigine is an antiepileptic drug that inhibits neuronal voltage-gated sodium channels, thus stabilizing neural impulse propagation and controlling seizure activity in the brain. However, lamotrigine has been shown to inhibit cardiac voltage-gated sodium channels resulting in a potential arrhythmogenic effect and the ability to unmask Brugada syndrome in genetically susceptible individuals. We are reporting a case of a 27-year-old male patient with a background of presumed idiopathic epilepsy who was initiated on lamotrigine therapy resulting in the unmasking of Brugada syndrome and the onset of syncopal episodes. This case provides further evidence for the arrhythmogenic capacity of lamotrigine and highlights the relationship between epilepsy and Brugada syndrome. In this report, we aim to review the current literature regarding the associations between epilepsy and Brugada syndrome and the impact of lamotrigine therapy on such patients.
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Affiliation(s)
- Hafiz Omer
- Department of Adult Cardiology, King Abdulaziz Medical City, Riyadh, Saudi Arabia
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- *Correspondence: Hafiz Omer,
| | - Mohamed H. Omer
- School of Medicine, Cardiff University, Cardiff, United Kingdom
| | | | - Ali M. Alzammam
- Department of Internal Medicine, King Abdulaziz Medical City, Riyadh, Saudi Arabia
| | - Omar Ahmad
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Haitham A. Alanazi
- Department of Adult Cardiology, King Abdulaziz Medical City, Riyadh, Saudi Arabia
- College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
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11
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Epilepsy-Induced High Affinity Blockade of the Cardiac Sodium Current INa by Lamotrigine; A Potential for Acquired Arrythmias. Pharmaceuticals (Basel) 2022; 15:ph15101208. [PMID: 36297320 PMCID: PMC9609666 DOI: 10.3390/ph15101208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/20/2022] [Accepted: 09/22/2022] [Indexed: 11/30/2022] Open
Abstract
Lamotrigine is widely prescribed to treat bipolar neurological disorder and epilepsy. It exerts its antiepileptic action by blocking voltage-gated sodium channels in neurons. Recently, the US Food and Drug Administration issued a warning on the use of Lamotrigine after observations of conduction anomalies and Brugada syndrome patterns on the electrocardiograms of epileptic patients treated with the drug. Brugada syndrome and conduction disturbance are both associated with alterations of the cardiac sodium current (INa) kinetics and amplitude. In this study, we used the patch clamp technique on cardiomyocytes from epileptic rats to test the hypothesis that Lamotrigine also blocks INa in the heart. We found that Lamotrigine inhibited 60% of INa peak amplitude and reduced cardiac excitability in epileptic rats but had little effect in sham animals. Moreover, Lamotrigine inhibited 67% of INaL and, more importantly, prolonged the action potential refractory period in epileptic animals. Our results suggest that enhanced affinity of Lamotrigine for INa may in part explain the clinical phenotypes observed in epileptic patients.
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12
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Merseburg A, Kasemir J, Buss EW, Leroy F, Bock T, Porro A, Barnett A, Tröder SE, Engeland B, Stockebrand M, Moroni A, Siegelbaum S, Isbrandt D, Santoro B. Seizures, behavioral deficits and adverse drug responses in two new genetic mouse models of HCN1 epileptic encephalopathy. eLife 2022; 11:70826. [PMID: 35972069 PMCID: PMC9481245 DOI: 10.7554/elife.70826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/15/2022] [Indexed: 11/13/2022] Open
Abstract
De novo mutations in voltage- and ligand-gated channels have been associated with an increasing number of cases of developmental and epileptic encephalopathies, which often fail to respond to classic antiseizure medications. Here, we examine two knock-in mouse models replicating de novo sequence variations in the HCN1 voltage-gated channel gene, p.G391D and p.M153I (Hcn1G380D/+ and Hcn1M142I/+ in mouse), associated with severe drug-resistant neonatal- and childhood-onset epilepsy, respectively. Heterozygous mice from both lines displayed spontaneous generalized tonic-clonic seizures. Animals replicating the p.G391D variant had an overall more severe phenotype, with pronounced alterations in the levels and distribution of HCN1 protein, including disrupted targeting to the axon terminals of basket cell interneurons. In line with clinical reports from patients with pathogenic HCN1 sequence variations, administration of the antiepileptic Na+ channel antagonists lamotrigine and phenytoin resulted in the paradoxical induction of seizures in both mouse lines, consistent with an effect to further impair inhibitory neuron function. We also show that these variants can render HCN1 channels unresponsive to classic antagonists, indicating the need to screen mutated channels to identify novel compounds with diverse mechanism of action. Our results underscore the necessity of tailoring effective therapies for specific channel gene variants, and how strongly validated animal models may provide an invaluable tool towards reaching this objective.
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Affiliation(s)
- Andrea Merseburg
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Jacquelin Kasemir
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Eric W Buss
- Department of Neuroscience, Columbia University, New York, United States
| | - Felix Leroy
- Department of Neuroscience, Columbia University, New York, United States
| | - Tobias Bock
- Department of Neuroscience, Columbia University, New York, United States
| | | | - Anastasia Barnett
- Department of Neuroscience, Columbia University, New York, United States
| | - Simon E Tröder
- Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Birgit Engeland
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Malte Stockebrand
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Anna Moroni
- Department of Biosciences, University of Milan, Milan, Italy
| | - Steve Siegelbaum
- Department of Neuroscience, Columbia University, New York, United States
| | - Dirk Isbrandt
- Experimental Neurophysiology, German Center for Neurodegenerative Diseases, Cologne, Germany
| | - Bina Santoro
- Department of Neuroscience, Columbia University, New York, United States
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13
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Ingleby-Talecki L, van Dijkman SC, Oosterholt SP, Della Pasqua O, Winter C, Cunnington M, Rebar L, Forero-Schwanhaeuser S, Patel V, Cooper JA, Bahinski A, Chaudhary KW. Cardiac sodium channel inhibition by lamotrigine: in vitro characterization and clinical implications. Clin Transl Sci 2022; 15:1978-1989. [PMID: 35579204 PMCID: PMC9372421 DOI: 10.1111/cts.13311] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/26/2022] [Accepted: 05/02/2022] [Indexed: 11/26/2022] Open
Abstract
Lamotrigine, approved for use as an antiseizure medication as well as the treatment of bipolar disorder, inhibits sodium channels in the brain to reduce repetitive neuronal firing and pathological release of glutamate. The shared homology of sodium channels and lack of selectivity associated with channel blocking agents can cause slowing of cardiac conduction and increased proarrhythmic potential. The Vaughan‐Williams classification system differentiates sodium channel blockers using biophysical properties of binding. As such, Class Ib inhibitors, including mexiletine, do not slow cardiac conduction as measured by the electrocardiogram, at therapeutically relevant exposure. Our goal was to characterize the biophysical properties of NaV1.5 block and to support the observed clinical safety of lamotrigine. We used HEK‐293 cells stably expressing the hNaV1.5 channel and voltage clamp electrophysiology to quantify the potency (half‐maximal inhibitory concentration) against peak and late channel current, on‐/off‐rate binding kinetics, voltage‐dependence, and tonic block of the cardiac sodium channel by lamotrigine; and compared to clinically relevant Class Ia (quinidine), Ib (mexiletine), and Ic (flecainide) inhibitors. Lamotrigine blocked peak and late NaV1.5 current at therapeutically relevant exposure, with rapid kinetics and biophysical properties similar to the class Ib inhibitor mexiletine. However, no clinically meaningful prolongation in QRS or PR interval was observed in healthy subjects in a new analysis of a previously reported thorough QT clinical trial (SCA104648). In conclusion, the weak NaV1.5 block and rapid kinetics do not translate into clinically relevant conduction slowing at therapeutic exposure and support the clinical safety of lamotrigine in patients suffering from epilepsy and bipolar disorder.
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Affiliation(s)
| | | | | | | | | | | | - Linda Rebar
- GSK US Regulatory Affairs, Collegeville, PA 19426, USA
| | | | - Vickas Patel
- Former GSK Employee, Collegeville, PA 19426, USA
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14
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Lin YC, Lai YC, Lin TH, Yang YC, Kuo CC. Selective stabilization of the intermediate inactivated Na+ channel by the new-generation anticonvulsant rufinamide. Biochem Pharmacol 2022; 197:114928. [DOI: 10.1016/j.bcp.2022.114928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/13/2022] [Accepted: 01/13/2022] [Indexed: 11/27/2022]
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15
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Scorpion Venom peptide, AGAP inhibits TRPV1 and potentiates the analgesic effect of lidocaine. Heliyon 2021; 7:e08560. [PMID: 35005265 PMCID: PMC8715296 DOI: 10.1016/j.heliyon.2021.e08560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/04/2021] [Accepted: 12/01/2021] [Indexed: 11/20/2022] Open
Abstract
The current study was designed to test the hypothesis that BmK AGAP (AGAP) potentiates the analgesic effect of lidocaine. The chronic constrictive injury was performed on 72 rats to induce a rapid onset and long-lasting pain. The rats were randomly assigned to one of six groups; Group A (n = 12) received an intrathecal administration of saline, Group B (n = 12) received an intrathecal injection of lidocaine, Group C (n = 12) received an intrathecal administration of AGAP, Group D, E, and F (n = 12 each) received an intrathecal administration of lidocaine 0.005 mg/ml + AGAP 25, 50, 100 μg/kg respectively. The von Frey filaments were used to assess mechanical allodynia. Nav1.7 and TRPV1 currents were recorded by the whole-cell aspiration patch-clamp technique, and KCNQ2/3 currents were recorded by the whole-cell drilling patch-clamp technique. The whole-cell aspiration patch-clamp technique showed that AGAP inhibited TRPV1and KCNQ2/3 currents and increased the analgesic effect of lidocaine. AGAP may have a synergistic effect with lidocaine which demonstrates a potential therapeutic approach for optimizing post-operative analgesia.
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16
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Hadley S, Patil MJ, Pavelkova N, Kollarik M, Taylor-Clark TE. Contribution of tetrodotoxin-sensitive, voltage-gated sodium channels (Na V1) to action potential discharge from mouse esophageal tension mechanoreceptors. Am J Physiol Regul Integr Comp Physiol 2021; 321:R672-R686. [PMID: 34523364 PMCID: PMC8616622 DOI: 10.1152/ajpregu.00199.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 11/22/2022]
Abstract
Action potentials depend on voltage-gated sodium channels (NaV1s), which have nine α subtypes. NaV1 inhibition is a target for pathologies involving excitable cells such as pain. However, because NaV1 subtypes are widely expressed, inhibitors may inhibit regulatory sensory systems. Here, we investigated specific NaV1s and their inhibition in mouse esophageal mechanoreceptors-non-nociceptive vagal sensory afferents that are stimulated by low threshold mechanical distension, which regulate esophageal motility. Using single fiber electrophysiology, we found mechanoreceptor responses to esophageal distension were abolished by tetrodotoxin. Single-cell RT-PCR revealed that esophageal-labeled TRPV1-negative vagal neurons expressed multiple tetrodotoxin-sensitive NaV1s: NaV1.7 (almost all neurons) and NaV1.1, NaV1.2, and NaV1.6 (in ∼50% of neurons). Inhibition of NaV1.7, using PF-05089771, had a small inhibitory effect on mechanoreceptor responses to distension. Inhibition of NaV1.1 and NaV1.6, using ICA-121341, had a similar small inhibitory effect. The combination of PF-05089771 and ICA-121341 inhibited but did not eliminate mechanoreceptor responses. Inhibition of NaV1.2, NaV1.6, and NaV1.7 using LSN-3049227 inhibited but did not eliminate mechanoreceptor responses. Thus, all four tetrodotoxin-sensitive NaV1s contribute to action potential initiation from esophageal mechanoreceptors terminals. This is different to those NaV1s necessary for vagal action potential conduction, as demonstrated using GCaMP6s imaging of esophageal vagal neurons during electrical stimulation. Tetrodotoxin-sensitive conduction was abolished in many esophageal neurons by PF-05089771 alone, indicating a critical role of NaV1.7. In summary, multiple NaV1 subtypes contribute to electrical signaling in esophageal mechanoreceptors. Thus, inhibition of individual NaV1s would likely have minimal effect on afferent regulation of esophageal motility.
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Affiliation(s)
- Stephen Hadley
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Mayur J Patil
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Nikoleta Pavelkova
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Marian Kollarik
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
| | - Thomas E Taylor-Clark
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida
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17
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Kahveci FO, Kahveci R, Gokce EC, Gokce A, Kısa Ü, Sargon MF, Fesli R, Sarı MF, Gürer B. Biochemical, pathological and ultrastructural investigation of whether lamotrigine has neuroprotective efficacy against spinal cord ischemia reperfusion injury. Injury 2021; 52:2803-2812. [PMID: 34391576 DOI: 10.1016/j.injury.2021.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/26/2021] [Accepted: 08/02/2021] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Lamotrigine, an anticonvulsant drug with inhibition properties of multi-ion channels, has been shown to be able to attenuates secondary neuronal damage by influencing different pathways. The aim of this study was to look into whether lamotrigine treatment could protect the spinal cord from experimental spinal cord ischemia-reperfusion injury. MATERIALS AND METHODS Thirty-two rats, eight rats per group, were randomly assigned to the sham group in which only laparotomy was performed, and to the ischemia, methylprednisolone and lamotrigine groups, where the infrarenal aorta was clamped for thirty minutes to induce spinal cord ischemia-reperfusion injury. Tissue samples belonging to spinal cords were harvested from sacrificed animals twenty-four hours after reperfusion. Tumor necrosis factor-alpha levels, interleukin-1 beta levels, nitric oxide levels, superoxide dismutase activity, catalase activity, glutathione peroxidase activity, malondialdehyde levels and caspase-3 activity were studied. Light and electron microscopic evaluations were also performed to reveal the pathological alterations. Basso, Beattie, and Bresnahan locomotor scale and the inclined-plane test was used to evaluate neurofunctional status at the beginning of the study and just before the animals were sacrificed. RESULTS Lamotrigine treatment provided significant improvement in the neurofunctional status by preventing the increase in cytokine expression, increased lipid peroxidation and oxidative stress, depletion of antioxidant enzymes activity and increased apoptosis, all of which contributing to spinal cord damage through different paths after ischemia reperfusion injury. Furthermore, lamotrigine treatment has shown improved results concerning the histopathological and ultrastructural scores and the functional tests. CONCLUSION These results proposed that lamotrigine may be a useful therapeutic agent to prevent the neuronal damage developing after spinal cord ischemia-reperfusion injury.
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Affiliation(s)
- Fatih Ozan Kahveci
- Department of Emergency Medicine, Balıkesir Atatürk City Hospital, Balıkesir, Turkey
| | - Ramazan Kahveci
- Department of Neurosurgery, Balıkesir University, Faculty of Medicine, Balıkesir, Turkey
| | - Emre Cemal Gokce
- Department of Neurosurgery, Abdurrahman Yurtaslan Ankara Oncology Education and Research Hospital, Ankara, Turkey
| | - Aysun Gokce
- Department of Pathology, Ministry of Health, Diskapi Yildirim Beyazit Education and Research Hospital, Ankara, Turkey
| | - Üçler Kısa
- Department of Biochemistry, Kirikkale University, Faculty of Medicine, Kirikkale, Turkey
| | - Mustafa Fevzi Sargon
- Department of Anatomy, Lokman Hekim University, Faculty of Medicine, Ankara, Turkey
| | - Ramazan Fesli
- Department of Neurosurgery, Mersin VM Medical Park Hospital, Mersin, Turkey
| | - Muhammed Fatih Sarı
- Department of Neurosurgery, Balıkesir University, Faculty of Medicine, Balıkesir, Turkey
| | - Bora Gürer
- Department of Neurosurgery, İstinye University, Faculty of Medicine, Istanbul, Turkey.
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18
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Lauxmann S, Sonnenberg L, Koch NA, Bosselmann C, Winter N, Schwarz N, Wuttke TV, Hedrich UBS, Liu Y, Lerche H, Benda J, Kegele J. Therapeutic Potential of Sodium Channel Blockers as a Targeted Therapy Approach in KCNA1-Associated Episodic Ataxia and a Comprehensive Review of the Literature. Front Neurol 2021; 12:703970. [PMID: 34566847 PMCID: PMC8459024 DOI: 10.3389/fneur.2021.703970] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 07/23/2021] [Indexed: 11/17/2022] Open
Abstract
Introduction: Among genetic paroxysmal movement disorders, variants in ion channel coding genes constitute a major subgroup. Loss-of-function (LOF) variants in KCNA1, the gene coding for KV1.1 channels, are associated with episodic ataxia type 1 (EA1), characterized by seconds to minutes-lasting attacks including gait incoordination, limb ataxia, truncal instability, dysarthria, nystagmus, tremor, and occasionally seizures, but also persistent neuromuscular symptoms like myokymia or neuromyotonia. Standard treatment has not yet been developed, and different treatment efforts need to be systematically evaluated. Objective and Methods: Personalized therapeutic regimens tailored to disease-causing pathophysiological mechanisms may offer the specificity required to overcome limitations in therapy. Toward this aim, we (i) reviewed all available clinical reports on treatment response and functional consequences of KCNA1 variants causing EA1, (ii) examined the potential effects on neuronal excitability of all variants using a single compartment conductance-based model and set out to assess the potential of two sodium channel blockers (SCBs: carbamazepine and riluzole) to restore the identified underlying pathophysiological effects of KV1.1 channels, and (iii) provide a comprehensive review of the literature considering all types of episodic ataxia. Results: Reviewing the treatment efforts of EA1 patients revealed moderate response to acetazolamide and exhibited the strength of SCBs, especially carbamazepine, in the treatment of EA1 patients. Biophysical dysfunction of KV1.1 channels is typically based on depolarizing shifts of steady-state activation, leading to an LOF of KCNA1 variant channels. Our model predicts a lowered rheobase and an increase of the firing rate on a neuronal level. The estimated concentration dependent effects of carbamazepine and riluzole could partially restore the altered gating properties of dysfunctional variant channels. Conclusion: These data strengthen the potential of SCBs to contribute to functional compensation of dysfunctional KV1.1 channels. We propose riluzole as a new drug repurposing candidate and highlight the role of personalized approaches to develop standard care for EA1 patients. These results could have implications for clinical practice in future and highlight the need for the development of individualized and targeted therapies for episodic ataxia and genetic paroxysmal disorders in general.
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Affiliation(s)
- Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Institute of Neurobiology, University of Tübingen, Tübingen, Germany
| | - Lukas Sonnenberg
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Institute of Neurobiology, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Nils A. Koch
- Institute of Neurobiology, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Christian Bosselmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Natalie Winter
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Niklas Schwarz
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thomas V. Wuttke
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
- Department of Neurosurgery, University of Tübingen, Tübingen, Germany
| | - Ulrike B. S. Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Yuanyuan Liu
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Jan Benda
- Institute of Neurobiology, University of Tübingen, Tübingen, Germany
- Bernstein Center for Computational Neuroscience Tübingen, Tübingen, Germany
| | - Josua Kegele
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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19
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Pal R, Kumar B, Akhtar MJ, Chawla PA. Voltage gated sodium channel inhibitors as anticonvulsant drugs: A systematic review on recent developments and structure activity relationship studies. Bioorg Chem 2021; 115:105230. [PMID: 34416507 DOI: 10.1016/j.bioorg.2021.105230] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/22/2021] [Accepted: 07/28/2021] [Indexed: 12/28/2022]
Abstract
Voltage-gated sodium channel blockers are one of the vital targets for the management of several central nervous system diseases, including epilepsy, chronic pain, psychiatric disorders, and spasticity. The voltage-gated sodium channels play a key role in controlling cellular excitability. This reduction in excitotoxicity is also applied to improve the symptoms of epileptic conditions. The effectiveness of antiepileptic drugs as sodium channel depends upon the reversible blocking of the spontaneous discharge without blocking its propagation. There are number of antiepileptic drug(s) which are in pipeline to flour the market to conquer abnormal neuronal excitability. They inhibit the seizures through the inhibition of complex voltage- and frequency-dependent ionic currents through sodium channels. Over the past decade, the sodium channel is one of the most explored targets to control or treat the seizure, but there has not been any game-changing discovery yet. Although there are large numbers of drugs approved for the treatment of epilepsy, however they are associated with several acute to chronic side effects. Many research groups have tirelessly worked for better therapeutic medication on this popular target to treat epileptic seizures. The review quotes briefly the developments of the approved examples of sodium channel blockers as anticonvulsant drugs. Medicinal chemists have tried the design and development of some more potent anticonvulsant drugs to minimize the toxicity that are discussed here, and an emphasis is given for their possible mechanism and the structure-activity relationship (SAR).
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Affiliation(s)
- Rohit Pal
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India
| | - Bhupinder Kumar
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India
| | - Md Jawaid Akhtar
- Department of Pharmaceutical Chemistry, College of Pharmacy, National University of Science and Technology, PO620, PC 130 Azaiba, Bousher, Muscat, Sultanate of Oman
| | - Pooja A Chawla
- Department of Pharmaceutical Chemistry, ISF College of Pharmacy, GT Road, Ghal Kalan, Moga 142001, Punjab, India.
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20
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Lin YC, Lai YC, Chou P, Hsueh SW, Lin TH, Huang CS, Wang RW, Yang YC, Kuo CC. How Can an Na + Channel Inhibitor Ameliorate Seizures in Lennox-Gastaut Syndrome? Ann Neurol 2021; 89:1099-1113. [PMID: 33745195 DOI: 10.1002/ana.26068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 02/23/2021] [Accepted: 03/14/2021] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Lennox-Gastaut syndrome (LGS) is an epileptic encephalopathy frequently associated with multiple types of seizures. The classical Na+ channel inhibitors are in general ineffective against the seizures in LGS. Rufinamide is a new Na+ channel inhibitor, but approved for the treatment of LGS. This is not consistent with a choice of antiseizure drugs (ASDs) according to simplistic categorical grouping. METHODS The effect of rufinamide on the Na+ channel, cellular discharges, and seizure behaviors was quantitatively characterized in native neurons and mammalian models of epilepsy, and compared with the other Na+ channel inhibitors. RESULTS With a much faster binding rate to the inactivated Na+ channel than phenytoin, rufinamide is distinctively effective if the seizure discharges chiefly involve short bursts interspersed with hyperpolarized interburst intervals, exemplified by spike and wave discharges (SWDs) on electroencephalograms. Consistently, rufinamide, but not phenytoin, suppresses SWD-associated seizures in pentylenetetrazol or AY-9944 models, which recapitulate the major electrophysiological and behavioral manifestations in typical and atypical absence seizures, including LGS. INTERPRETATION Na+ channel inhibitors shall have sufficiently fast binding to exert an action during the short bursts and then suppress SWDs, in which cases rufinamide is superior. For the epileptiform discharges where the interburst intervals are not so hyperpolarized, phenytoin could be better because of the higher affinity. Na+ channel inhibitors with different binding kinetics and affinity to the inactivated channels may have different antiseizure scope. A rational choice of ASDs according to in-depth molecular pharmacology and the attributes of ictal discharges is advisable. ANN NEUROL 2021;89:1099-1113.
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Affiliation(s)
- Yun-Chu Lin
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Yi-Chen Lai
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Ping Chou
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Shu-Wei Hsueh
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Tien-Hung Lin
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chen-Syuan Huang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Ren-Wei Wang
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Ya-Chin Yang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.,Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan.,Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou Medical Center, Tao-Yuan, Taiwan
| | - Chung-Chin Kuo
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
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21
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Gambeta E, Chichorro JG, Zamponi GW. Trigeminal neuralgia: An overview from pathophysiology to pharmacological treatments. Mol Pain 2021; 16:1744806920901890. [PMID: 31908187 PMCID: PMC6985973 DOI: 10.1177/1744806920901890] [Citation(s) in RCA: 129] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The trigeminal nerve (V) is the fifth and largest of all cranial nerves, and it is responsible for detecting sensory stimuli that arise from the craniofacial area. The nerve is divided into three branches: ophthalmic (V1), maxillary (V2), and mandibular (V3); their cell bodies are located in the trigeminal ganglia and they make connections with second-order neurons in the trigeminal brainstem sensory nuclear complex. Ascending projections via the trigeminothalamic tract transmit information to the thalamus and other brain regions responsible for interpreting sensory information. One of the most common forms of craniofacial pain is trigeminal neuralgia. Trigeminal neuralgia is characterized by sudden, brief, and excruciating facial pain attacks in one or more of the V branches, leading to a severe reduction in the quality of life of affected patients. Trigeminal neuralgia etiology can be classified into idiopathic, classic, and secondary. Classic trigeminal neuralgia is associated with neurovascular compression in the trigeminal root entry zone, which can lead to demyelination and a dysregulation of voltage-gated sodium channel expression in the membrane. These alterations may be responsible for pain attacks in trigeminal neuralgia patients. The antiepileptic drugs carbamazepine and oxcarbazepine are the first-line pharmacological treatment for trigeminal neuralgia. Their mechanism of action is a modulation of voltage-gated sodium channels, leading to a decrease in neuronal activity. Although carbamazepine and oxcarbazepine are the first-line treatment, other drugs may be useful for pain control in trigeminal neuralgia. Among them, the anticonvulsants gabapentin, pregabalin, lamotrigine and phenytoin, baclofen, and botulinum toxin type A can be coadministered with carbamazepine or oxcarbazepine for a synergistic approach. New pharmacological alternatives are being explored such as the active metabolite of oxcarbazepine, eslicarbazepine, and the new Nav1.7 blocker vixotrigine. The pharmacological profiles of these drugs are addressed in this review.
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Affiliation(s)
- Eder Gambeta
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Juliana G Chichorro
- Department of Pharmacology, Biological Sciences Sector, Federal University of Parana, Curitiba, Brazil
| | - Gerald W. Zamponi
- Department of Physiology and Pharmacology, Alberta Children's Hospital Research Institute and Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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22
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Hinckley CA, Kuryshev Y, Sers A, Barre A, Buisson B, Naik H, Hajos M. Characterization of Vixotrigine, a Broad-Spectrum Voltage-Gated Sodium Channel Blocker. Mol Pharmacol 2021; 99:49-59. [PMID: 33298520 DOI: 10.1124/molpharm.120.000079] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/15/2020] [Indexed: 02/02/2023] Open
Abstract
Voltage-gated sodium channels (Navs) are promising targets for analgesic and antiepileptic therapies. Although specificity between Nav subtypes may be desirable to target specific neural types, such as nociceptors in pain, many broadly acting Nav inhibitors are clinically beneficial in neuropathic pain and epilepsy. Here, we present the first systematic characterization of vixotrigine, a Nav blocker. Using recombinant systems, we find that vixotrigine potency is enhanced in a voltage- and use-dependent manner, consistent with a state-dependent block of Navs. Furthermore, we find that vixotrigine potently inhibits sodium currents produced by both peripheral and central nervous system Nav subtypes, with use-dependent IC50 values between 1.76 and 5.12 μM. Compared with carbamazepine, vixotrigine shows higher potency and more profound state-dependent inhibition but a similar broad spectrum of action distinct from Nav1.7- and Nav1.8-specific blockers. We find that vixotrigine rapidly inhibits Navs and prolongs recovery from the fast-inactivated state. In native rodent dorsal root ganglion sodium channels, we find that vixotrigine shifts steady-state inactivation curves. Based on these results, we conclude that vixotrigine is a broad-spectrum, state-dependent Nav blocker. SIGNIFICANCE STATEMENT: Vixotrigine blocks both peripheral and central voltage-gated sodium channel subtypes. Neurophysiological approaches in recombinant systems and sensory neurons suggest this block is state-dependent.
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Affiliation(s)
- Christopher A Hinckley
- Biogen, Cambridge, Massachusetts (C.A.H., H.N.); Charles River Laboratories Cleveland, Inc., Cleveland, Ohio (Y.K.); Neuroservice, Aix-en-Provence, France (A.S., A.B., B.B.); and Department of Comparative Medicine, Yale University, New Haven, Connecticut (M.H.)
| | - Yuri Kuryshev
- Biogen, Cambridge, Massachusetts (C.A.H., H.N.); Charles River Laboratories Cleveland, Inc., Cleveland, Ohio (Y.K.); Neuroservice, Aix-en-Provence, France (A.S., A.B., B.B.); and Department of Comparative Medicine, Yale University, New Haven, Connecticut (M.H.)
| | - Alissende Sers
- Biogen, Cambridge, Massachusetts (C.A.H., H.N.); Charles River Laboratories Cleveland, Inc., Cleveland, Ohio (Y.K.); Neuroservice, Aix-en-Provence, France (A.S., A.B., B.B.); and Department of Comparative Medicine, Yale University, New Haven, Connecticut (M.H.)
| | - Alexander Barre
- Biogen, Cambridge, Massachusetts (C.A.H., H.N.); Charles River Laboratories Cleveland, Inc., Cleveland, Ohio (Y.K.); Neuroservice, Aix-en-Provence, France (A.S., A.B., B.B.); and Department of Comparative Medicine, Yale University, New Haven, Connecticut (M.H.)
| | - Bruno Buisson
- Biogen, Cambridge, Massachusetts (C.A.H., H.N.); Charles River Laboratories Cleveland, Inc., Cleveland, Ohio (Y.K.); Neuroservice, Aix-en-Provence, France (A.S., A.B., B.B.); and Department of Comparative Medicine, Yale University, New Haven, Connecticut (M.H.)
| | - Himanshu Naik
- Biogen, Cambridge, Massachusetts (C.A.H., H.N.); Charles River Laboratories Cleveland, Inc., Cleveland, Ohio (Y.K.); Neuroservice, Aix-en-Provence, France (A.S., A.B., B.B.); and Department of Comparative Medicine, Yale University, New Haven, Connecticut (M.H.)
| | - Mihaly Hajos
- Biogen, Cambridge, Massachusetts (C.A.H., H.N.); Charles River Laboratories Cleveland, Inc., Cleveland, Ohio (Y.K.); Neuroservice, Aix-en-Provence, France (A.S., A.B., B.B.); and Department of Comparative Medicine, Yale University, New Haven, Connecticut (M.H.)
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Enrique A, Martín P, Sbaraglini ML, Talevi A, Milesi V. Parabens inhibit hNa V 1.2 channels. Biomed Pharmacother 2020; 128:110250. [PMID: 32480218 DOI: 10.1016/j.biopha.2020.110250] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/27/2020] [Accepted: 05/10/2020] [Indexed: 10/24/2022] Open
Abstract
Propylparaben, a commonly used antimicrobial preservative, has been reported as an anticonvulsant agent targeting neuronal Na+ channels (NaV). However, the specific features of the NaV channel inhibition by this agent have so far not been extensively studied. Moreover, it is still unclear if it shares this pharmacological activity with other parabens. Here, we fully characterized the mechanism of action of the inhibitory effect that propylparaben and benzylparaben induce on human NaV 1.2 channel isoform (hNaV1.2). We established a first approach to know the parabens structural determinants for this channel inhibition. The parabens effects on hNaV1.2 channel mediated currents were recorded using the patch-clamp whole-cell configuration on hNaV1.2 stably transfected HEK293 cells. Propylparaben induced a typical state-dependent inhibition on hNaV1.2 channel carried current, characterized by a left-shift in the steady-state inactivation curve, a prolongation in the time needed for recovery from fast inactivation and a frequency-dependent blocking behavior. The state-dependent inhibition is increased for butylparaben and benzylparaben and diminished for methylparaben, ethylparaben and p-hydroxybenzoic acid (the major metabolite of parabens hydrolysis). Particularly, butylparaben and benzylparaben shift the steady-state inactivation curve 2- and 3-times more than propylparaben, respectively. Parabens are blockers of hNaV1.2 channels, sharing the mechanism of action of most of sodium channel blocking antiseizure drugs. The potency of this inhibition increases with the size of the lipophilic alcoholic residue of the ester group. These results provide a basis for rational drug design directed to generate new potential anticonvulsant agents.
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Affiliation(s)
- Andrea Enrique
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, Facultad de Ciencias Exactas, La Plata, Argentina.
| | - Pedro Martín
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, Facultad de Ciencias Exactas, La Plata, Argentina.
| | - María Laura Sbaraglini
- Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.
| | - Alan Talevi
- Laboratorio de Investigación y Desarrollo de Bioactivos (LIDeB), Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Argentina.
| | - Verónica Milesi
- Instituto de Estudios Inmunológicos y Fisiopatológicos (IIFP), UNLP, CONICET, asociado CIC PBA, Facultad de Ciencias Exactas, La Plata, Argentina.
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24
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PharmGKB summary: lamotrigine pathway, pharmacokinetics and pharmacodynamics. Pharmacogenet Genomics 2020; 30:81-90. [PMID: 32187155 DOI: 10.1097/fpc.0000000000000397] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Inhibition of Fast Nerve Conduction Produced by Analgesics and Analgesic Adjuvants-Possible Involvement in Pain Alleviation. Pharmaceuticals (Basel) 2020; 13:ph13040062. [PMID: 32260535 PMCID: PMC7243109 DOI: 10.3390/ph13040062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/29/2020] [Accepted: 04/01/2020] [Indexed: 02/07/2023] Open
Abstract
Nociceptive information is transmitted from the periphery to the cerebral cortex mainly by action potential (AP) conduction in nerve fibers and chemical transmission at synapses. Although this nociceptive transmission is largely inhibited at synapses by analgesics and their adjuvants, it is possible that the antinociceptive drugs inhibit nerve AP conduction, contributing to their antinociceptive effects. Many of the drugs are reported to inhibit the nerve conduction of AP and voltage-gated Na+ and K+ channels involved in its production. Compound action potential (CAP) is a useful measure to know whether drugs act on nerve AP conduction. Clinically-used analgesics and analgesic adjuvants (opioids, non-steroidal anti-inflammatory drugs, 2-adrenoceptor agonists, antiepileptics, antidepressants and local anesthetics) were found to inhibit fast-conducting CAPs recorded from the frog sciatic nerve by using the air-gap method. Similar actions were produced by antinociceptive plant-derived chemicals. Their inhibitory actions depended on the concentrations and chemical structures of the drugs. This review article will mention the inhibitory actions of the antinociceptive compounds on CAPs in frog and mammalian peripheral (particularly, sciatic) nerves and on voltage-gated Na+ and K+ channels involved in AP production. Nerve AP conduction inhibition produced by analgesics and analgesic adjuvants is suggested to contribute to at least a part of their antinociceptive effects.
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26
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Antiarrhythmic Mechanisms of Chinese Herbal Medicine Dingji Fumai Decoction. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:9185707. [PMID: 32256664 PMCID: PMC7109552 DOI: 10.1155/2020/9185707] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 01/16/2020] [Accepted: 01/29/2020] [Indexed: 12/11/2022]
Abstract
Background Dingji Fumai decoction (DFD) is used to treat ventricular arrhythmia, and it has provided a very good curative effect. However, its cellular electrophysiological mechanism is unknown. Methods Electrocardiogram was recorded, and oxidative stress response and ion-channel-related molecules were detected in rats with barium chloride- and aconitine-induced ventricular arrhythmia. Moreover, whole-cell patch-clamp assay was used to investigate the inhibitory effect of DFD on Nav1.5 in Chinese hamster ovary cells. Results DFD prolonged the occurrence time and shortened the duration of ventricular arrhythmia, decreased the malondialdehyde and increased the superoxide dismutase, and alleviated the activation of Na+-K+-ATPase and connexin-43. DFD suppressed Nav1.5dose-dependently with an IC50 of 24.0 ± 2.4 mg/mL. Conclusions The clinical antiarrhythmic mechanisms of DFD are based on its antioxidant potential, alleviation of Na+-K+-ATPase and connexin-43, and class I antiarrhythmic properties by suppressing Nav1.5dose-dependently with an IC50 of 24.0 ± 2.4 mg/mL.
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27
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Suzuki-Muromoto S, Kosaki R, Kosaki K, Kubota M. Familial hemiplegic migraine with a PRRT2 mutation: Phenotypic variations and carbamazepine efficacy. Brain Dev 2020; 42:293-297. [PMID: 31902651 DOI: 10.1016/j.braindev.2019.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 12/11/2019] [Accepted: 12/11/2019] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To understand the clinical characteristics of familial hemiplegic migraine (FHM) caused by a PRRT2 mutation and to examine the efficacy of preventive treatment. METHODS Using the literature, we investigated clinical details of FHM in 3 generations of patients with a PRRT2 mutation and compared them with those in 17 patients with the same mutation from 6 families. RESULTS In most of the affected patients, the onset was observed during the teen years. Complicated phenotypes tended to be shared in each family, and five patients showed spontaneous remission. With regard to treatment, low-dose carbamazepine (CBZ) was effective in three patients. CONCLUSION Considering the clinical features, we suggest that low-dose CBZ is efficacious for FHM treatment in patients with a PRRT2 mutation. The treatment duration should be carefully considered because some patients show spontaneous remission. More accumulated data from familial cases might help elucidate PRRT2 function and establish standard treatment for FHM.
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Affiliation(s)
- Sato Suzuki-Muromoto
- Division of Neurology, National Center for Child Health and Development, Tokyo, Japan.
| | - Rika Kosaki
- Division of Medical Genetics, National Center for Child Health and Development, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Masaya Kubota
- Division of Neurology, National Center for Child Health and Development, Tokyo, Japan
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28
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Nomura S, Kida H, Hirayama Y, Imoto H, Inoue T, Moriyama H, Mitsushima D, Suzuki M. Reduction of spike generation frequency by cooling in brain slices from rats and from patients with epilepsy. J Cereb Blood Flow Metab 2019; 39:2286-2294. [PMID: 30117752 PMCID: PMC6827110 DOI: 10.1177/0271678x18795365] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
This study aimed to understand the mechanism by which brain cooling terminates epileptic discharge. Cortical slices were prepared from rat brains (n = 19) and samples from patients with intractable epilepsy that had undergone temporal lobectomy (n = 7). We performed whole cell current clamp recordings at approximately physiological brain temperature (35℃) and at cooler temperatures (25℃ and 15℃). The firing threshold in human neurons was lower at 25℃ (-32.6 mV) than at 35℃ (-27.0 mV). The resting potential and spike frequency were similar at 25℃ and 35℃. Cooling from 25℃ to 15℃ did not change the firing threshold, but the resting potential increased from -65.5 to -54.0 mV and the waveform broadened from 1.85 to 6.55 ms, due to delayed repolarization. These changes enhanced the initial spike appearance and reduced spike frequency; moreover, spike frequency was insensitive to increased levels of current injections. Similar results were obtained in rat brain studies. We concluded that the reduction in spike frequency at 15℃, due to delayed repolarization, might be a key mechanism by which brain cooling terminates epileptic discharge. On the other hand, spike frequency was not influenced by the reduced firing threshold or the elevated resting potential caused by cooling.
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Affiliation(s)
- Sadahiro Nomura
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.,Epilepsy Center, Yamaguchi University Hospital, Yamaguchi, Japan
| | - Hiroyuki Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Yuya Hirayama
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Hirochika Imoto
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.,Epilepsy Center, Yamaguchi University Hospital, Yamaguchi, Japan
| | - Takao Inoue
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Hiroshi Moriyama
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Michiyasu Suzuki
- Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
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Van Hook MJ, Nawy S, Thoreson WB. Voltage- and calcium-gated ion channels of neurons in the vertebrate retina. Prog Retin Eye Res 2019; 72:100760. [PMID: 31078724 PMCID: PMC6739185 DOI: 10.1016/j.preteyeres.2019.05.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/25/2019] [Accepted: 05/01/2019] [Indexed: 02/06/2023]
Abstract
In this review, we summarize studies investigating the types and distribution of voltage- and calcium-gated ion channels in the different classes of retinal neurons: rods, cones, horizontal cells, bipolar cells, amacrine cells, interplexiform cells, and ganglion cells. We discuss differences among cell subtypes within these major cell classes, as well as differences among species, and consider how different ion channels shape the responses of different neurons. For example, even though second-order bipolar and horizontal cells do not typically generate fast sodium-dependent action potentials, many of these cells nevertheless possess fast sodium currents that can enhance their kinetic response capabilities. Ca2+ channel activity can also shape response kinetics as well as regulating synaptic release. The L-type Ca2+ channel subtype, CaV1.4, expressed in photoreceptor cells exhibits specific properties matching the particular needs of these cells such as limited inactivation which allows sustained channel activity and maintained synaptic release in darkness. The particular properties of K+ and Cl- channels in different retinal neurons shape resting membrane potentials, response kinetics and spiking behavior. A remaining challenge is to characterize the specific distributions of ion channels in the more than 100 individual cell types that have been identified in the retina and to describe how these particular ion channels sculpt neuronal responses to assist in the processing of visual information by the retina.
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Affiliation(s)
- Matthew J Van Hook
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA
| | - Scott Nawy
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA; Department Pharmacology & Experimental Neuroscience(2), University of Nebraska Medical Center, Omaha, NE, USA
| | - Wallace B Thoreson
- Truhlsen Eye Institute, Department of Ophthalmology & Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA; Department Pharmacology & Experimental Neuroscience(2), University of Nebraska Medical Center, Omaha, NE, USA.
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Nakatani Y, Amano T. Functional Modulation of Na v1.2 Voltage-Gated Sodium Channels Induced by Escitalopram. Biol Pharm Bull 2018; 41:1471-1474. [DOI: 10.1248/bpb.b18-00214] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yoshihiko Nakatani
- Department of Pharmacotherapeutics, School of Pharmacy, International University of Health and Welfare
| | - Taku Amano
- Department of Pharmacotherapeutics, School of Pharmacy, International University of Health and Welfare
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Polyamine Modulation of Anticonvulsant Drug Response: A Potential Mechanism Contributing to Pharmacoresistance in Chronic Epilepsy. J Neurosci 2018; 38:5596-5605. [PMID: 29789377 DOI: 10.1523/jneurosci.0640-18.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/07/2018] [Accepted: 05/12/2018] [Indexed: 11/21/2022] Open
Abstract
Despite the development of numerous novel anticonvulsant drugs, ∼30% of epilepsy patients remain refractory to antiepileptic drugs (AEDs). Many established and novel AEDs reduce hyperexcitability via voltage- and use-dependent inhibition of voltage-gated Na+ channels. For the widely used anticonvulsant carbamazepine (CBZ), use-dependent block of Na+ channels is significantly reduced both in experimental and human epilepsy. However, the molecular underpinnings of this potential cellular mechanism for pharmacoresistance have remained enigmatic.Here, we describe the mechanism that leads to the emergence of CBZ-resistant Na+ channels. We focused on the endogenous polyamine system, which powerfully modulates Na+ channels in a use-dependent manner. We had shown previously that the intracellular polyamine spermine is reduced in chronic epilepsy, resulting in increased persistent Na+ currents. Because spermine and CBZ both bind use-dependently in spatial proximity within the Na+ channel pore, we hypothesized that spermine loss might also be related to diminished CBZ response. Using the pilocarpine model of refractory epilepsy in male rats and whole-cell patch-clamp recordings, we first replicated the reduction of use-dependent block by CBZ in chronically epileptic animals. We then substituted intracellular spermine via the patch pipette in different concentrations. Under these conditions, we found that exogenous spermine significantly rescues use-dependent block of Na+ channels by CBZ. These findings indicate that an unexpected modulatory mechanism, depletion of intracellular polyamines, leads both to increased persistent Na+ currents and to diminished CBZ sensitivity of Na+ channels. These findings could lead to novel strategies for overcoming pharmacoresistant epilepsy that target the polyamine system.SIGNIFICANCE STATEMENT Pharmacoresistant epilepsy affects ∼18 million people worldwide, and intense efforts have therefore been undertaken to uncover the underlying molecular and cellular mechanisms. One of the key known candidate mechanisms of pharmacoresistance has been a loss of use-dependent Na+ channel block by the anticonvulsant carbamazepine (CBZ), both in human and experimental epilepsies. Despite intense scrutiny, the molecular mechanisms underlying this phenomenon have not been elucidated. We now show that a loss of intracellular spermine in chronic epilepsy is a major causative factor leading to the development of CBZ-resistant Na+ currents. This finding can be exploited both for the screening of anticonvulsants in expression systems, and for novel strategies to overcome pharmacoresistance that target the polyamine system.
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Pastore V, Wasowski C, Martin P, Enrique A, Higgs J, Bruno-Blanch LE, Milesi V, Marder M. N-propyl-2,2-diphenyl-2-hydroxyacetamide, a novel α-hydroxyamide with anticonvulsant, anxiolytic and antidepressant-like effects that inhibits voltage-gated sodium channels. Eur J Pharmacol 2017; 819:270-280. [PMID: 29217174 DOI: 10.1016/j.ejphar.2017.11.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 11/14/2017] [Accepted: 11/30/2017] [Indexed: 01/08/2023]
Abstract
In patients with epilepsy, anxiety and depression are the most frequent psychiatric comorbidities but they often remain unrecognized and untreated. We report herein the antidepressant-like activity in two animal models, tail suspension and forced swimming tests, of six anticonvulsants α-hydroxyamides. From these, N-propyl-2,2-diphenyl-2-hydroxyacetamide (compound 5) emerged not only as the most active as anticonvulsant (ED50 = 2.5mg/kg, MES test), but it showed the most remarkable antidepressant-like effect in the tail suspension and forced swimming tests (0.3-30mg/kg, i.p.); and, also, anxiolytic-like action in the plus maze test (3-10mg/kg, i.p.) in mice. Studies of its mechanism of action, by means of its capacity to act via the GABAA receptor ([3H]-flunitrazepam binding assay); the 5-HT1A receptor ([3H]-8-OH-DPAT binding assay) and the voltage-gated sodium channels (either using the patch clamp technique in hNav 1.2 expressed in HEK293 cell line or using veratrine, in vivo) were attempted. The results demonstrated that its effects are not likely related to 5-HT1A or GABAAergic receptors and that its anticonvulsant and antidepressant-like effect could be due to its voltage-gated sodium channel blocking properties.
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Affiliation(s)
- Valentina Pastore
- Universidad de Buenos Aires, Consejo Nacional de lnvestigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Junín 956 (C1113AAD), Ciudad de Buenos Aires, Argentina.
| | - Cristina Wasowski
- Universidad de Buenos Aires, Consejo Nacional de lnvestigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Junín 956 (C1113AAD), Ciudad de Buenos Aires, Argentina.
| | - Pedro Martin
- Universidad Nacional de La Plata, Consejo Nacional de lnvestigaciones Científicas y Técnicas, Instituto de Estudios Inmunopatológicos y Fisiológicos, 47 street and 115 (B1900BJW), La Plata, Argentina.
| | - Andrea Enrique
- Química Medicinal, Departamento de Ciencias Biológicas, Universidad Nacional de La Plata, 47 street and 115 (B1900BJW), La Plata, Argentina.
| | - Josefina Higgs
- Universidad de Buenos Aires, Consejo Nacional de lnvestigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Junín 956 (C1113AAD), Ciudad de Buenos Aires, Argentina.
| | - Luis E Bruno-Blanch
- Química Medicinal, Departamento de Ciencias Biológicas, Universidad Nacional de La Plata, 47 street and 115 (B1900BJW), La Plata, Argentina.
| | - Veronica Milesi
- Universidad Nacional de La Plata, Consejo Nacional de lnvestigaciones Científicas y Técnicas, Instituto de Estudios Inmunopatológicos y Fisiológicos, 47 street and 115 (B1900BJW), La Plata, Argentina.
| | - Mariel Marder
- Universidad de Buenos Aires, Consejo Nacional de lnvestigaciones Científicas y Técnicas, Instituto de Química y Fisicoquímica Biológicas, Facultad de Farmacia y Bioquímica, Junín 956 (C1113AAD), Ciudad de Buenos Aires, Argentina.
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Bulleyaconitine A preferably reduces tetrodotoxin-sensitive sodium current in uninjured dorsal root ganglion neurons of neuropathic rats probably via inhibition of protein kinase C. Pain 2017; 158:2169-2180. [DOI: 10.1097/j.pain.0000000000001018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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James TF, Nenov MN, Tapia CM, Lecchi M, Koshy S, Green TA, Laezza F. Consequences of acute Na v1.1 exposure to deltamethrin. Neurotoxicology 2017; 60:150-160. [PMID: 28007400 PMCID: PMC5447465 DOI: 10.1016/j.neuro.2016.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 12/02/2016] [Accepted: 12/14/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Pyrethroid insecticides are the most popular class of insecticides in the world, despite their near-ubiquity, their effects of delaying the onset of inactivation of voltage-gated sodium (Nav) channels have not been well-evaluated in all the mammalian Nav isoforms. OBJECTIVE Here we compare the well-studied Nav1.6 isoforms to the less-understood Nav1.1 in their responses to acute deltamethrin exposure. METHODS We used patch-clamp electrophysiology to record sodium currents encoded by either Nav1.1 or Nav1.6 channels stably expressed in HEK293 cells. Protocols evaluating both resting and use-dependent modification were employed. RESULTS We found that exposure of both isoforms to 10μM deltamethrin significantly potentiated persistent and tail current densities without affecting peak transient current densities, and only Nav1.1 maintained these significant effects at 1μM deltamethrin. Window currents increased for both as well, and while only Nav1.6 displayed changes in activation slope and V1/2 of steady-state inactivation for peak currents, V1/2 of persistent current activation was hyperpolarized of ∼10mV by deltamethrin in Nav1.1 cells. Evaluating use-dependence, we found that deltamethrin again potentiated persistent and tail current densities in both isoforms, but only Nav1.6 demonstrated use-dependent enhancement, indicating the primary deltamethrin-induced effects on Nav1.1 channels are not use-dependent. CONCLUSION Collectively, these data provide evidence that Nav1.1 is indeed vulnerable to deltamethrin modification at lower concentrations than Nav1.6, and this effect is primarily mediated during the resting state. GENERAL SIGNIFICANCE These findings identify Nav1.1 as a novel target of pyrethroid exposure, which has major implications for the etiology of neuropsychiatric disorders associated with loss of Nav1.1-expressing inhibitory neurons.
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Affiliation(s)
- T F James
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, USA; Neuroscience Graduate Program, University of Texas Medical Branch, USA
| | - Miroslav N Nenov
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, USA
| | - Cynthia M Tapia
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, USA
| | - Marzia Lecchi
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Italy
| | - Shyny Koshy
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, USA; Center for Addiction Research, University of Texas Medical Branch, USA
| | - Thomas A Green
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, USA; Center for Addiction Research, University of Texas Medical Branch, USA
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, USA; Mitchell Center for Neurodegenerative Diseases, USA; Center for Environmental Toxicology, University of Texas Medical Branch, USA; Center for Addiction Research, University of Texas Medical Branch, USA.
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Hulbert J, Elger CE, Meyer R, Surges R. Antiepileptic Drugs Impair Shortening of Isolated Cardiomyocytes. Front Neurol 2017; 8:133. [PMID: 28421035 PMCID: PMC5376916 DOI: 10.3389/fneur.2017.00133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/21/2017] [Indexed: 11/28/2022] Open
Abstract
Background Most antiepileptic drugs (AEDs) inhibit seizure generation by acting on voltage-dependent ion channels. Voltage-dependent sodium and calcium channels are commonly expressed in brain and heart, suggesting that AEDs may have considerable cardiodepressive effects, thereby facilitating sudden cardiac death as a potential cause of sudden unexpected death in epilepsy. Here, we investigated the effects of carbamazepine (CBZ), lamotrigine (LTG), and levetiracetam (LEV) alone and in combination on the shortening properties of isolated ventricular cardiomyocytes of wild-type mice. Methods Properties of murine cardiomyocytes were determined by recording the sarcomere shortening with a video imaging system before, during, and after administration of AEDs in different concentrations and combinations. We assessed (i) the number of successful shortenings during continuous electrical stimulation (electromechanical coupling) and (ii) the shortening amplitude as well as other shortening-related properties upon repetitive electrical stimulation at 4 Hz. Data are given as mean ± SEM. Results At 100 μM, CBZ (10 cells), LTG (11 cells), and LEV (11 cells) alone had no effect on the electromechanical coupling but reversibly reduced shortening amplitudes by 15 ± 4, 24 ± 3, and 11 ± 3%, respectively. Increasing the LTG concentration to 250 (21 cells) and 500 μM (4 cells) reversibly inhibited the electromechanical coupling in 62 and 100% of the experiments. Importantly, simultaneous application of CBZ, LTG, and LEV at 100 μM also impaired the electromechanical coupling in 8 of 19 cardiomyocytes (42%) and reduced the shortening amplitude by 21 ± 4%. Conclusion Our data show that AEDs reversibly impair cardiac excitation and contraction. Importantly, the blocking effect on electromechanical coupling appears to be additive when different AEDs are simultaneously applied. The translational value of these experimental findings into clinical practice is limited. Our results, however, suggest that rationale AED therapy may be important with respect to cardiac side effects and potential facilitation of serious cardiac dysfunction especially when AEDs are used in combination or at very high doses.
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Affiliation(s)
- Johanna Hulbert
- Institute of Physiology II, University Hospital Bonn, Bonn, Germany
| | | | - Rainer Meyer
- Institute of Physiology II, University Hospital Bonn, Bonn, Germany
| | - Rainer Surges
- Department of Epileptology, University Hospital Bonn, Bonn, Germany
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Phenytoin: a step by step insight into its multiple mechanisms of action-80 years of mechanistic studies in neuropharmacology. J Neurol 2017; 264:2043-2047. [PMID: 28349209 DOI: 10.1007/s00415-017-8465-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Revised: 03/14/2017] [Accepted: 03/15/2017] [Indexed: 12/15/2022]
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Jo S, Bean BP. Lacosamide Inhibition of Nav1.7 Voltage-Gated Sodium Channels: Slow Binding to Fast-Inactivated States. Mol Pharmacol 2017; 91:277-286. [PMID: 28119481 DOI: 10.1124/mol.116.106401] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 01/18/2017] [Indexed: 11/22/2022] Open
Abstract
Lacosamide is an antiseizure agent that targets voltage-dependent sodium channels. Previous experiments have suggested that lacosamide is unusual in binding selectively to the slow-inactivated state of sodium channels, in contrast to drugs like carbamazepine and phenytoin, which bind tightly to fast-inactivated states. Using heterologously expressed human Nav1.7 sodium channels, we examined the state-dependent effects of lacosamide. Lacosamide induced a reversible shift in the voltage dependence of fast inactivation studied with 100-millisecond prepulses, suggesting binding to fast-inactivated states. Using steady holding potentials, lacosamide block was very weak at -120 mV (3% inhibition by 100 µM lacosamide) but greatly enhanced at -80 mV (43% inhibition by 100 µM lacosamide), where there is partial fast inactivation but little or no slow inactivation. During long depolarizations, lacosamide slowly (over seconds) put channels into states that recovered availability slowly (hundreds of milliseconds) at -120 mV. This resembles enhancement of slow inactivation, but the effect was much more pronounced at -40 mV, where fast inactivation is complete, but slow inactivation is not, than at 0 mV, where slow inactivation is maximal, more consistent with slow binding to fast-inactivated states than selective binding to slow-inactivated states. Furthermore, inhibition by lacosamide was greatly reduced by pretreatment with 300 µM lidocaine or 300 µM carbamazepine, suggesting that lacosamide, lidocaine, and carbamazepine all bind to the same site. The results suggest that lacosamide binds to fast-inactivated states in a manner similar to other antiseizure agents but with slower kinetics of binding and unbinding.
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Affiliation(s)
- Sooyeon Jo
- Department of Neurobiology, Harvard Medical School, Boston Massachusetts
| | - Bruce P Bean
- Department of Neurobiology, Harvard Medical School, Boston Massachusetts
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Cappaert NLM, Werkman TR, Benito N, Witter MP, Baayen JC, Wadman WJ. Carbamazepine modulates the spatiotemporal activity in the dentate gyrus of rats and pharmacoresistant humans in vitro. Brain Behav 2016; 6:e00463. [PMID: 27110437 PMCID: PMC4834359 DOI: 10.1002/brb3.463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 11/11/2022] Open
Abstract
INTRODUCTION Human hippocampal tissue resected from pharmacoresistant epilepsy patients was investigated to study the effect of the antiepileptic drug CBZ (carbamazepine) and was compared to similar experiments in the hippocampus of control rats. METHODS The molecular layer of the DG (dentate gyrus) of human epileptic tissue and rat nonepileptic tissue was electrically stimulated and the evoked responses were recorded with voltage-sensitive dye imaging to characterize the spatiotemporal properties. RESULTS Bath applied CBZ (100 μmol/L) reduced the amplitude of the evoked responses in the human DG, albeit that no clear use-dependent effects were found at frequencies of 8 or 16 Hz. In nonepileptic control DG from rats, CBZ also reduced the amplitude of the evoked response in the molecular layer of the DG as well as the spatial extent of the response. CONCLUSIONS This study demonstrates that CBZ still reduced the activity in the DG, although the patients were clinically diagnosed as pharmacoresistant for CBZ. This suggests that in the human epileptic brain, the targets of CBZ, the voltage-gated Na(+) channels, are still sensitive to CBZ, although we used a relative high concentration and it is not possibility to assess the actual CBZ concentration that reached the target in the patient. We also concluded that the effect of CBZ was found in the activated region of the DG, quite comparable to the observations in the nonepileptic rat.
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Affiliation(s)
- Natalie L M Cappaert
- Swammerdam Institute for Life Sciences - Center for NeuroScience University of Amsterdam Amsterdam The Netherlands
| | - Taco R Werkman
- Swammerdam Institute for Life Sciences - Center for NeuroScience University of Amsterdam Amsterdam The Netherlands
| | - Nuria Benito
- Swammerdam Institute for Life Sciences - Center for NeuroScience University of Amsterdam Amsterdam The Netherlands
| | - Menno P Witter
- Department of Anatomy and Neuroscience Institute for Clinical and Experimental Neurosciences VU University Medical Center Amsterdam The Netherlands
| | - Johannes C Baayen
- Department of Neurosurgery VU University Medical Center Amsterdam The Netherlands
| | - Wytse J Wadman
- Swammerdam Institute for Life Sciences - Center for NeuroScience University of Amsterdam Amsterdam The Netherlands
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Zhang H, Reichert E, Cohen AE. Optical electrophysiology for probing function and pharmacology of voltage-gated ion channels. eLife 2016; 5. [PMID: 27215841 PMCID: PMC4907688 DOI: 10.7554/elife.15202] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 05/12/2016] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated ion channels mediate electrical dynamics in excitable tissues and are an important class of drug targets. Channels can gate in sub-millisecond timescales, show complex manifolds of conformational states, and often show state-dependent pharmacology. Mechanistic studies of ion channels typically involve sophisticated voltage-clamp protocols applied through manual or automated electrophysiology. Here, we develop all-optical electrophysiology techniques to study activity-dependent modulation of ion channels, in a format compatible with high-throughput screening. Using optical electrophysiology, we recapitulate many voltage-clamp protocols and apply to Nav1.7, a channel implicated in pain. Optical measurements reveal that a sustained depolarization strongly potentiates the inhibitory effect of PF-04856264, a Nav1.7-specific blocker. In a pilot screen, we stratify a library of 320 FDA-approved compounds by binding mechanism and kinetics, and find close concordance with patch clamp measurements. Optical electrophysiology provides a favorable tradeoff between throughput and information content for studies of NaV channels, and possibly other voltage-gated channels. DOI:http://dx.doi.org/10.7554/eLife.15202.001 Ion channels are specialized proteins that span the cell membrane. When activated, these channels allow ions to pass through them, which can produce electrical spikes that carry information in nerve cells and regulate the beating of the heart. Researchers interested in understanding how ion channels behave often use a technique called patch clamp electrophysiology to measure the electrical current across the cell membrane. The technique can be used to probe if a specific drug can block an ion channel, but it is not well suited to screening lots of potential drugs because it is slow and expensive. A group of ion channels known as voltage-gated sodium channels play an important role in generating the electrical spikes in nerve cells. One subtype called NaV1.7 is involved in sensing pain and drugs that block NaV1.7 might be useable as painkillers, but only if they are specific to this channel. This is because there are many similar sodium channels that are important in other processes in the body. Zhang et al. have now developed a new light-based technique to measure how ion channels behave. The technique uses light to activate the channel and a fluorescent protein to report on the membrane’s voltage. Zhang et al. used the new technique to probe how sodium channels, in particular NaV1.7, interact with drugs. Mammalian cells grown in the lab were engineered to produce NaV1.7, a light-activated ion channel (called CheRiff), and a fluorescent reporter protein. A flash of blue light delivered to the cells activated CheRiff, which in turn activated NaV1.7. At the same time, the fluorescence of the reporter protein was used as a read-out of NaV1.7’s activity. Zhang et al. showed that they could reproduce many conventional electrophysiology measurements using their new light-based approach. Optical measurements were then used to screen 320 drugs to see whether they could block NaV1.7. The results of the screen corresponded closely with measurements made using conventional electrophysiology. These results demonstrate that the new optical technique is both fast and precise enough to be used in drug discovery. Further studies could now ask if this optical technique can also be used to study other ion channels, such as potassium channels and calcium channels. DOI:http://dx.doi.org/10.7554/eLife.15202.002
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Affiliation(s)
- Hongkang Zhang
- Departments of Chemistry and Chemical Biology and Physics, Harvard University, Cambridge, United States.,Howard Hughes Medical Institute, Harvard University, Cambridge, United States
| | - Elaine Reichert
- Departments of Chemistry and Chemical Biology and Physics, Harvard University, Cambridge, United States
| | - Adam E Cohen
- Departments of Chemistry and Chemical Biology and Physics, Harvard University, Cambridge, United States.,Howard Hughes Medical Institute, Harvard University, Cambridge, United States
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Zhao F, Li X, Jin L, Zhang F, Inoue M, Yu B, Cao Z. Development of a Rapid Throughput Assay for Identification of hNav1.7 Antagonist Using Unique Efficacious Sodium Channel Agonist, Antillatoxin. Mar Drugs 2016; 14:md14020036. [PMID: 26891306 PMCID: PMC4771989 DOI: 10.3390/md14020036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 01/21/2016] [Accepted: 01/26/2016] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are responsible for the generation of the action potential. Among nine classified VGSC subtypes (Nav1.1–Nav1.9), Nav1.7 is primarily expressed in the sensory neurons, contributing to the nociception transmission. Therefore Nav1.7 becomes a promising target for analgesic drug development. In this study, we compared the influence of an array of VGSC agonists including veratridine, BmK NT1, brevetoxin-2, deltamethrin and antillatoxin (ATX) on membrane depolarization which was detected by Fluorescence Imaging Plate Reader (FLIPR) membrane potential (FMP) blue dye. In HEK-293 cells heterologously expressing hNav1.7 α-subunit, ATX produced a robust membrane depolarization with an EC50 value of 7.8 ± 2.9 nM whereas veratridine, BmK NT1, and deltamethrin produced marginal response. Brevetoxin-2 was without effect on membrane potential change. The ATX response was completely inhibited by tetrodotoxin suggesting that the ATX response was solely derived from hNav1.7 activation, which was consistent with the results where ATX produced a negligible response in null HEK-293 cells. Six VGSC antagonists including lidocaine, lamotrigine, phenytoin, carbamazepine, riluzole, and 2-amino-6-trifluoromethylthiobenzothiazole all concentration-dependently inhibited ATX response with IC50 values comparable to that reported from patch-clamp experiments. Considered together, we demonstrate that ATX is a unique efficacious hNav1.7 activator which offers a useful probe to develop a rapid throughput screening assay to identify hNav1.7 antagonists.
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Affiliation(s)
- Fang Zhao
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China.
- Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing 211198, China.
| | - Xichun Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China.
- Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing 211198, China.
| | - Liang Jin
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China.
- School of Life Science and Technology, China Pharmaceutical University, Nanjing 211198, China.
| | - Fan Zhang
- Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing 211198, China.
| | - Masayuki Inoue
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Boyang Yu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China.
- Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing 211198, China.
| | - Zhengyu Cao
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 211198, China.
- Jiangsu Provincial Key laboratory for TCM Evaluation and Translational Development, China Pharmaceutical University, Nanjing 211198, China.
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Millan MJ, Goodwin GM, Meyer-Lindenberg A, Ove Ögren S. Learning from the past and looking to the future: Emerging perspectives for improving the treatment of psychiatric disorders. Eur Neuropsychopharmacol 2015; 25:599-656. [PMID: 25836356 DOI: 10.1016/j.euroneuro.2015.01.016] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 01/28/2015] [Indexed: 02/06/2023]
Abstract
Modern neuropsychopharmacology commenced in the 1950s with the serendipitous discovery of first-generation antipsychotics and antidepressants which were therapeutically effective yet had marked adverse effects. Today, a broader palette of safer and better-tolerated agents is available for helping people that suffer from schizophrenia, depression and other psychiatric disorders, while complementary approaches like psychotherapy also have important roles to play in their treatment, both alone and in association with medication. Nonetheless, despite considerable efforts, current management is still only partially effective, and highly-prevalent psychiatric disorders of the brain continue to represent a huge personal and socio-economic burden. The lack of success in discovering more effective pharmacotherapy has contributed, together with many other factors, to a relative disengagement by pharmaceutical firms from neuropsychiatry. Nonetheless, interest remains high, and partnerships are proliferating with academic centres which are increasingly integrating drug discovery and translational research into their traditional activities. This is, then, a time of transition and an opportune moment to thoroughly survey the field. Accordingly, the present paper, first, chronicles the discovery and development of psychotropic agents, focusing in particular on their mechanisms of action and therapeutic utility, and how problems faced were eventually overcome. Second, it discusses the lessons learned from past successes and failures, and how they are being applied to promote future progress. Third, it comprehensively surveys emerging strategies that are (1), improving our understanding of the diagnosis and classification of psychiatric disorders; (2), deepening knowledge of their underlying risk factors and pathophysiological substrates; (3), refining cellular and animal models for discovery and validation of novel therapeutic agents; (4), improving the design and outcome of clinical trials; (5), moving towards reliable biomarkers of patient subpopulations and medication efficacy and (6), promoting collaborative approaches to innovation by uniting key partners from the regulators, industry and academia to patients. Notwithstanding the challenges ahead, the many changes and ideas articulated herein provide new hope and something of a framework for progress towards the improved prevention and relief of psychiatric and other CNS disorders, an urgent mission for our Century.
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Affiliation(s)
- Mark J Millan
- Pole for Innovation in Neurosciences, IDR Servier, 125 chemin de ronde, 78290 Croissy sur Seine, France.
| | - Guy M Goodwin
- University Department of Psychiatry, Oxford University, Warneford Hospital, Oxford OX3 7JX, England, UK
| | - Andreas Meyer-Lindenberg
- Central Institute of Mental Health, University of Heidelberg/Medical Faculty Mannheim, J5, D-68159 Mannheim, Germany
| | - Sven Ove Ögren
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, S-17177 Stockholm, Sweden
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Tadros MA, Farrell KE, Graham BA, Brichta AM, Callister RJ. Properties of sodium currents in neonatal and young adult mouse superficial dorsal horn neurons. Mol Pain 2015; 11:17. [PMID: 25889748 PMCID: PMC4381457 DOI: 10.1186/s12990-015-0014-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 02/16/2015] [Indexed: 12/11/2022] Open
Abstract
Background Superficial dorsal horn (SDH) neurons process nociceptive information and their excitability is partly determined by the properties of voltage-gated sodium channels. Recently, we showed the excitability and action potential properties of mouse SDH neurons change markedly during early postnatal development. Here we compare sodium currents generated in neonate (P0-5) and young adult (≥P21) SDH neurons. Results Whole cell recordings were obtained from lumbar SDH neurons in transverse spinal cord slices (CsF internal, 32°C). Fast activating and inactivating TTX-sensitive inward currents were evoked by depolarization from a holding potential of −100 mV. Poorly clamped currents, based on a deflection in the IV relationship at potentials between −60 and −50 mV, were not accepted for analysis. Current density and decay time increased significantly between the first and third weeks of postnatal development, whereas time to peak was similar at both ages. This was accompanied by more subtle changes in activation range and steady state inactivation. Recovery from inactivation was slower and TTX-sensitivity was reduced in young adult neurons. Conclusions Our study suggests sodium channel expression changes markedly during early postnatal development in mouse SDH neurons. The methods employed in this study can now be applied to future investigations of spinal cord sodium channel plasticity in murine pain models.
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Affiliation(s)
- Melissa A Tadros
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine and Hunter Medical Research Institute, The University of Newcastle, Callaghan, Newcastle, NSW, 2308, Australia.
| | - Kristen E Farrell
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine and Hunter Medical Research Institute, The University of Newcastle, Callaghan, Newcastle, NSW, 2308, Australia.
| | - Brett A Graham
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine and Hunter Medical Research Institute, The University of Newcastle, Callaghan, Newcastle, NSW, 2308, Australia.
| | - Alan M Brichta
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine and Hunter Medical Research Institute, The University of Newcastle, Callaghan, Newcastle, NSW, 2308, Australia.
| | - Robert J Callister
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine and Hunter Medical Research Institute, The University of Newcastle, Callaghan, Newcastle, NSW, 2308, Australia.
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López-Pérez SJ, Morales-Villagrán A, Medina-Ceja L. Effect of perinatal asphyxia and carbamazepine treatment on cortical dopamine and DOPAC levels. J Biomed Sci 2015; 22:14. [PMID: 25889791 PMCID: PMC4335632 DOI: 10.1186/s12929-015-0117-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/23/2015] [Indexed: 01/29/2023] Open
Abstract
Background One of the most important manifestations of perinatal asphyxia is the occurrence of seizures, which are treated with antiepileptic drugs, such as carbamazepine. These early seizures, combined with pharmacological treatments, may influence the development of dopaminergic neurotransmission in the frontal cortex. This study aimed to determine the extracellular levels of dopamine and its main metabolite DOPAC in 30-day-old rats that had been asphyxiated for 45 min in a low (8%) oxygen chamber at a perinatal age and treated with daily doses of carbamazepine. Quantifications were performed using microdialysis coupled to a high-performance liquid chromatography (HPLC) system in basal conditions and following the use of the chemical stimulus. Results Significant decreases in basal and stimulated extracellular dopamine and DOPAC content were observed in the frontal cortex of the asphyxiated group, and these decreases were partially recovered in the animals administered daily doses of carbamazepine. Greater basal dopamine concentrations were also observed as an independent effect of carbamazepine. Conclusions Perinatal asphyxia plus carbamazepine affects extracellular levels of dopamine and DOPAC in the frontal cortex and stimulated the release of dopamine, which provides evidence for the altered availability of dopamine in cortical brain areas during brain development.
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Affiliation(s)
- Silvia J López-Pérez
- Laboratorio de Neurofisiología y Neuroquímica, Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez #2100, Predio Las Agujas, Zapopan, Jalisco, C.P 44600, Mexico.
| | - Alberto Morales-Villagrán
- Laboratorio de Neurofisiología y Neuroquímica, Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez #2100, Predio Las Agujas, Zapopan, Jalisco, C.P 44600, Mexico.
| | - Laura Medina-Ceja
- Laboratorio de Neurofisiología y Neuroquímica, Departamento de Biología Celular y Molecular, CUCBA, Universidad de Guadalajara, Camino Ing. Ramón Padilla Sánchez #2100, Predio Las Agujas, Zapopan, Jalisco, C.P 44600, Mexico.
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Effects of various antiepileptics used to alleviate neuropathic pain on compound action potential in frog sciatic nerves: comparison with those of local anesthetics. BIOMED RESEARCH INTERNATIONAL 2014; 2014:540238. [PMID: 24707490 PMCID: PMC3953671 DOI: 10.1155/2014/540238] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/24/2013] [Accepted: 01/07/2014] [Indexed: 11/17/2022]
Abstract
Antiepileptics used for treating neuropathic pain have various actions including voltage-gated Na(+) and Ca(2+) channels, glutamate-receptor inhibition, and GABA(A)-receptor activation, while local anesthetics are also used to alleviate the pain. It has not been fully examined yet how nerve conduction inhibitions by local anesthetics differ in extent from those by antiepileptics. Fast-conducting compound action potentials (CAPs) were recorded from frog sciatic nerve fibers by using the air-gap method. Antiepileptics (lamotrigine and carbamazepine) concentration dependently reduced the peak amplitude of the CAP (IC50 = 0.44 and 0.50 mM, resp.). Carbamazepine analog oxcarbazepine exhibited an inhibition smaller than that of carbamazepine. Antiepileptic phenytoin (0.1 mM) reduced CAP amplitude by 15%. On the other hand, other antiepileptics (gabapentin, sodium valproate, and topiramate) at 10 mM had no effect on CAPs. The CAPs were inhibited by local anesthetic levobupivacaine (IC50 = 0.23 mM). These results indicate that there is a difference in the extent of nerve conduction inhibition among antiepileptics and that some antiepileptics inhibit nerve conduction with an efficacy similar to that of levobupivacaine or to those of other local anesthetics (lidocaine, ropivacaine, and cocaine) as reported previously. This may serve to know a contribution of nerve conduction inhibition in the antinociception by antiepileptics.
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