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Schierscher T, Singh N, Kobel A, Wild J, Bauland F, Geistanger A, Risch L, Geletneky C, Seger C, Taibon J. An isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS)-based candidate reference measurement procedure for the quantification of carbamazepine-10,11-epoxide in human serum and plasma. Clin Chem Lab Med 2024; 62:1339-1351. [PMID: 38515344 DOI: 10.1515/cclm-2023-1045] [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: 09/18/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024]
Abstract
OBJECTIVES A reference measurement procedure (RMP) using isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) was developed and validated with the aim of accurately measuring carbamazepine-10,11-epoxide concentrations in human serum and plasma. METHODS To establish traceability to SI units, the absolute content of the reference material was determined using quantitative nuclear magnetic resonance (qNMR) spectroscopy. As sample preparation a protein precipitation protocol followed by a high dilution step was established. Chromatographic separation from carbamazepine and potential metabolites was achieved using a C18 stationary phase. Selectivity, specificity, matrix effects, precision and accuracy, inter-laboratory equivalence, and uncertainty of measurement were evaluated based on guidelines from the Clinical and Laboratory Standards Institute, the International Conference on Harmonization, and the Guide to the Expression of Uncertainty in Measurement. RESULTS The RMP demonstrated very good selectivity and specificity, showing no evidence of a matrix effect. This enabled accurate quantification of carbamazepine-epoxide in the concentration range of 0.0400-12.0 μg/mL. The intermediate precision was found to be less than 2.1 %, and the repeatability coefficient of variation (CV) ranged from 1.2 to 1.8 % across all concentration levels. Regarding accuracy, the relative mean bias varied from 1.4 to 2.5 % for native serum levels and from 1.4 to 3.5 % for Li-heparin plasma levels. The measurement uncertainty for single measurements ranged from 1.6 to 2.1 %. CONCLUSIONS In this study, we introduce a new LC-MS/MS-based candidate RMP for accurately measuring carbamazepine-10,11-epoxide in human serum and plasma. This novel method offers a traceable and dependable platform, making it suitable for standardizing routine assays and assessing clinically relevant samples.
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Affiliation(s)
| | - Neeraj Singh
- 111618 Roche Diagnostics GmbH , Penzberg, Germany
| | - Anja Kobel
- 58117 Dr. Risch Ostschweiz AG , Buchs, Switzerland
| | - Janik Wild
- 58117 Dr. Risch Ostschweiz AG , Buchs, Switzerland
| | | | | | - Lorenz Risch
- 58117 Dr. Risch Ostschweiz AG , Buchs, Switzerland
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Kavuran Buran İ, Onalan Etem E, Tektemur A. Inhibition of TRPC1, TRPM4 and CHRNA6 Ion Channels Ameliorates Depression-Like Behavior in Rats. Behav Brain Res 2022; 423:113765. [DOI: 10.1016/j.bbr.2022.113765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/31/2021] [Accepted: 01/17/2022] [Indexed: 11/02/2022]
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Zampatti S, Fabrizio C, Ragazzo M, Campoli G, Caputo V, Strafella C, Pellicano C, Cascella R, Spalletta G, Petrosini L, Caltagirone C, Termine A, Giardina E. Precision Medicine into Clinical Practice: A Web-Based Tool Enables Real-Time Pharmacogenetic Assessment of Tailored Treatments in Psychiatric Disorders. J Pers Med 2021; 11:jpm11090851. [PMID: 34575628 PMCID: PMC8471120 DOI: 10.3390/jpm11090851] [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: 07/21/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 12/16/2022] Open
Abstract
The management of neuropsychiatric disorders involves different pharmacological treatments. In order to perform efficacious drug treatments, the metabolism of CYP genes can help to foresee potential drug–drug interactions. The NeuroPGx software is an open-source web-based tool for genotype/diplotype/phenotype interpretation for neuropharmacogenomic purposes. The software provides information about: (i) the genotypes of evaluated SNPs (single nucleotide polymorphisms); (ii) the main diplotypes in CYP genes and corresponding metabolization phenotypes; (iii) the list of neuropsychiatric drugs with recommended dosage adjustment (according to CPIC and DPWG guidelines); (iv) the list of possible (rare) diplotypes and corresponding metabolization phenotypes. The combined application of NeuroPGx software to the OpenArray technology results in an easy, quick, and highly automated device ready to be used in routine clinical practice.
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Affiliation(s)
- Stefania Zampatti
- Genomic Medicine Laboratory UILDM, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (S.Z.); (C.F.); (G.C.); (C.S.); (R.C.); (A.T.)
| | - Carlo Fabrizio
- Genomic Medicine Laboratory UILDM, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (S.Z.); (C.F.); (G.C.); (C.S.); (R.C.); (A.T.)
| | - Michele Ragazzo
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, 00133 Rome, Italy; (M.R.); (V.C.)
| | - Giulia Campoli
- Genomic Medicine Laboratory UILDM, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (S.Z.); (C.F.); (G.C.); (C.S.); (R.C.); (A.T.)
| | - Valerio Caputo
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, 00133 Rome, Italy; (M.R.); (V.C.)
| | - Claudia Strafella
- Genomic Medicine Laboratory UILDM, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (S.Z.); (C.F.); (G.C.); (C.S.); (R.C.); (A.T.)
| | - Clelia Pellicano
- Laboratory of Neuropsychiatry, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy; (C.P.); (G.S.)
| | - Raffaella Cascella
- Genomic Medicine Laboratory UILDM, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (S.Z.); (C.F.); (G.C.); (C.S.); (R.C.); (A.T.)
- Department of Biomedical Sciences, Catholic University Our Lady of Good Counsel, 1000 Tirana, Albania
| | - Gianfranco Spalletta
- Laboratory of Neuropsychiatry, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, 00179 Rome, Italy; (C.P.); (G.S.)
| | - Laura Petrosini
- Department of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy;
| | - Carlo Caltagirone
- Department of Clinical and Behavioral Neurology, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy;
| | - Andrea Termine
- Genomic Medicine Laboratory UILDM, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (S.Z.); (C.F.); (G.C.); (C.S.); (R.C.); (A.T.)
| | - Emiliano Giardina
- Genomic Medicine Laboratory UILDM, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy; (S.Z.); (C.F.); (G.C.); (C.S.); (R.C.); (A.T.)
- Department of Biomedicine and Prevention, Tor Vergata University of Rome, 00133 Rome, Italy; (M.R.); (V.C.)
- Correspondence:
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Osuntokun OS, Babatunde AA, Olayiwola G, Atere TG, Oladokun OO, Adedokun KI. Assessment of the biomarkers of hepatotoxicity following carbamazepine, levetiracetam, and carbamazepine-levetiracetam adjunctive treatment in male Wistar rats. Toxicol Rep 2021; 8:592-598. [PMID: 33786324 PMCID: PMC7994541 DOI: 10.1016/j.toxrep.2021.03.008] [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: 05/13/2020] [Revised: 02/27/2021] [Accepted: 03/06/2021] [Indexed: 11/15/2022] Open
Abstract
Objective This study examined some of the biomarkers of hepatotoxicity following chronic treatment with carbamazepine (CBZ), levetiracetam (LEV), and CBZ + LEV adjunctive treatment in male rats. Method Twenty-four male Wistar rats (140-150 g) were randomized into four groups (n = 6) to receive oral dose of normal saline (0.1 mL), CBZ (25 mg/kg), LEV (50 mg/kg) or sub-therapeutic dose of CBZ (12.5 mg/kg) together with LEV (25 mg/kg) for 28 days. Activities of the liver enzymes and oxidative stress markers were determined while liver histomorphology was also carried out. Data were analyzed using descriptive and inferential statistics. The results were presented as mean ± SEM in graphs or tables, while the level of significance was taken at p < 0.05. Results The activities of alkaline-phosphatase and malondialdehyde concentrations increased significantly in all the drug treatment groups, while the activities of superoxide dismutase decreased significantly following CBZ, and CBZ + LEV treatment. Alanine-aminotransferase activities increased significantly in the CBZ and CBZ + LEV treated rats compared with control. The liver section of CBZ treated rats showed mild vascular congestion. Conclusion None of these AEDs treatment is devoid of hepatotoxicity. However, the adverse effects in CBZ were greater than LEV, or CBZ + LEV adjunctive treatment.
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Affiliation(s)
- Opeyemi Samson Osuntokun
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Osun State University Osogbo, Nigeria
| | - Ademola Adeniyi Babatunde
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Osun State University Osogbo, Nigeria
| | - Gbola Olayiwola
- Department of Clinical Pharmacy and Pharmacy Administration, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Tope Gafar Atere
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, Osun State University, Osogbo, Nigeria
| | - Olayemi Olutobi Oladokun
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Osun State University Osogbo, Nigeria
| | - Kabiru Isola Adedokun
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Osun State University Osogbo, Nigeria
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Chbili C, Hassine A, Ben Amor S, Nouira M, Ben Ammou S, Saguem S. Implications of metabolic parameters of carbamazepine in the therapeutic monitoring of Tunisian patients with epilepsy. Rev Neurol (Paris) 2016; 172:313-7. [PMID: 27062293 DOI: 10.1016/j.neurol.2015.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 11/17/2015] [Accepted: 12/18/2015] [Indexed: 10/22/2022]
Abstract
Carbamazepine (CBZ) is widely used in the control of simple and complex focal seizures and generalized tonic-clonic seizures in patients with epilepsy. The toxic effects of CBZ are not easily predicted, and this is due to the difficulty of delivering the optimal dose and/or plasma concentration of CBZ necessary to achieve beneficial effects, and especially to prevent the onset of toxicity associated with its use. Our study aimed to determine the relationship between the administered daily dose of CBZ and its pharmacokinetic parameters, including concentrations of CBZ and carbamazepine-10,11-epoxide (CBZ-E) plasma levels, and the metabolic ratio of CBZ-E to CBZ, in Tunisian patients with epilepsy. To accomplish this, a high-performance liquid chromatography method with ultraviolet detection was used for quantification in the simultaneous analysis of CBZ and one of its active metabolites, CBZ-E, in human plasma. A statistically significant positive correlation was found between the daily doses administered (mg/kg/day) and plasma concentrations of CBZ and CBZ-E, and the CBZ-E/CBZ ratio increased significantly as a function of the specific dose (in mg/kg/day). The increase in plasma concentrations of CBZ-E was non-linear in relation to plasma concentrations of CBZ, and there was no correlation between the CBZ-E/CBZ metabolic ratio and CBZ plasma concentrations. Our findings suggest that monitoring of CBZ as well as CBZ-E blood levels should be considered, as it may play a useful role in the therapeutic management of patients with epilepsy.
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Affiliation(s)
- C Chbili
- Medicine Faculty of Sousse, Department of Biophysics, Laboratory of Metabolic Biophysics, Professional Toxicology and Applied Environnemental, avenue Mohamed Karoui, Sousse, Tunisia.
| | - A Hassine
- Central Hospital University (CHU), Neurology Department, Sousse, Tunisia
| | - S Ben Amor
- Central Hospital University (CHU), Neurology Department, Sousse, Tunisia
| | - M Nouira
- Medicine Faculty of Sousse, Department of Biophysics, Laboratory of Metabolic Biophysics, Professional Toxicology and Applied Environnemental, avenue Mohamed Karoui, Sousse, Tunisia
| | - S Ben Ammou
- Central Hospital University (CHU), Neurology Department, Sousse, Tunisia
| | - S Saguem
- Medicine Faculty of Sousse, Department of Biophysics, Laboratory of Metabolic Biophysics, Professional Toxicology and Applied Environnemental, avenue Mohamed Karoui, Sousse, Tunisia.
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Desaphy JF, Carbonara R, Costanza T, Conte Camerino D. Preclinical evaluation of marketed sodium channel blockers in a rat model of myotonia discloses promising antimyotonic drugs. Exp Neurol 2014; 255:96-102. [PMID: 24613829 PMCID: PMC4004800 DOI: 10.1016/j.expneurol.2014.02.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Revised: 02/17/2014] [Accepted: 02/26/2014] [Indexed: 12/25/2022]
Abstract
Although the sodium channel blocker mexiletine is considered the first-line drug in myotonia, some patients experiment adverse effects, while others do not gain any benefit. Other antimyotonic drugs are thus needed to offer mexiletine alternatives. In the present study, we used a previously-validated rat model of myotonia congenita to compare six marketed sodium channel blockers to mexiletine. Myotonia was induced in the rat by injection of anthracen-9-carboxylic acid, a muscle chloride channel blocker. The drugs were given orally and myotonia was evaluated by measuring the time of righting reflex. The drugs were also tested on sodium currents recorded in a cell line transfected with the human skeletal muscle sodium channel hNav1.4 using patch-clamp technique. In vivo, carbamazepine and propafenone showed antimyotonic activity at doses similar to mexiletine (ED50 close to 5mg/kg); flecainide and orphenadrine showed greater potency (ED50 near 1mg/kg); lubeluzole and riluzole were the more potent (ED50 near 0.1mg/kg). The antimyotonic activity of drugs in vivo was linearly correlated with their potency in blocking hNav1.4 channels in vitro. Deviation was observed for propafenone and carbamazepine, likely due to pharmacokinetics and multiple targets. The comparison of the antimyotonic dose calculated in rats with the current clinical dose in humans strongly suggests that all the tested drugs may be used safely for the treatment of human myotonia. Considering the limits of mexiletine tolerability and the occurrence of non-responders, this study proposes an arsenal of alternative drugs, which may prove useful to increase the quality of life of individuals suffering from non-dystrophic myotonia. Further clinical trials are warranted to confirm these results.
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Affiliation(s)
- Jean-François Desaphy
- Section of Pharmacology, Department of Pharmacy & Drug Sciences, University of Bari-Aldo Moro, Bari I-70125, Italy.
| | - Roberta Carbonara
- Section of Pharmacology, Department of Pharmacy & Drug Sciences, University of Bari-Aldo Moro, Bari I-70125, Italy
| | - Teresa Costanza
- Section of Pharmacology, Department of Pharmacy & Drug Sciences, University of Bari-Aldo Moro, Bari I-70125, Italy
| | - Diana Conte Camerino
- Section of Pharmacology, Department of Pharmacy & Drug Sciences, University of Bari-Aldo Moro, Bari I-70125, Italy
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Ficarra S, Misiti F, Russo A, Carelli-Alinovi C, Bellocco E, Barreca D, Laganà G, Leuzzi U, Toscano G, Giardina B, Galtieri A, Tellone E. Antiepileptic carbamazepine drug treatment induces alteration of membrane in red blood cells: possible positive effects on metabolism and oxidative stress. Biochimie 2012; 95:833-41. [PMID: 23246915 DOI: 10.1016/j.biochi.2012.11.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 11/30/2012] [Indexed: 12/17/2022]
Abstract
Carbamazepine (CBZ) is an iminostilbene derivative commonly used for treatment of neuralgic pain and bipolar affective disorders. CBZ blood levels of treated patients are within the range of micromolar concentrations and therefore, significant interactions of this drug with erythrocytes are very likely. Moreover, the lipid domains of the cell membrane are believed to be one of the sites where iminostilbene derivatives exert their effects. The present study aimed to deeply characterize CBZ effects on erythrocytes, in order to identify extra and/or cytosolic cell targets. Our results indicate that erythrocyte morphological changes promoted by the drug, may be triggered by an alteration in band 3 functionality i.e. at the level of anionic flux. In addition, from a metabolic point of view this perturbation could be considered, at least in part, as a beneficial event because it could favour the CO2 elimination. Since lipid peroxidation, superoxide and free radical scavenging activities, caspase 3 activity and hemoglobin (Hb) functionality were not modified within the CBZ treated red blood cell (RBC), band 3 protein (B3) may well be a specific membrane target for CBZ and responsible for CBZ-induced toxic effects in erythrocytes. However some beneficial effects of this drug have been evidenced; among them an increased release of ATP and nitric oxide (NO) derived metabolites from erythrocytes to lumen, leading to an increased NO pool in the vasculature. In conclusion, these results indicate that CBZ, though considered responsible for toxic effects on erythrocytes, can also exhibit effects that at least in some conditions may be seen as beneficial.
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Affiliation(s)
- Silvana Ficarra
- Department of Chemical Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres 31, 98166 Messina, Italy.
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Occurrence and Elimination of Pharmaceuticals During Conventional Wastewater Treatment. THE HANDBOOK OF ENVIRONMENTAL CHEMISTRY 2012. [DOI: 10.1007/978-3-642-25722-3_1] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Ambrósio AF, Soares-Da-Silva P, Carvalho CM, Carvalho AP. Mechanisms of action of carbamazepine and its derivatives, oxcarbazepine, BIA 2-093, and BIA 2-024. Neurochem Res 2002; 27:121-30. [PMID: 11926264 DOI: 10.1023/a:1014814924965] [Citation(s) in RCA: 216] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Carbamazepine (CBZ) has been extensively used in the treatment of epilepsy, as well as in the treatment of neuropathic pain and affective disorders. However, the mechanisms of action of this drug are not completely elucidated and are still a matter of debate. Since CBZ is not very effective in some epileptic patients and may cause several adverse effects, several antiepileptic drugs have been developed by structural variation of CBZ, such as oxcarbazepine (OXC), which is used in the treatment of epilepsy since 1990. (S)-(-)-10-acetoxy-10,11-dihydro-5H-dibenz [b,f]azepine-5-carboxamide (BIA 2-093) and 10,11-dihydro-10-hydroxyimino-5H-dibenz[b,f] azepine-5-carboxamide (BIA 2-024), which were recently developed by BIAL, are new putative antiepileptic drugs, with some improved properties. In this review, we will focus on the mechanisms of action of CBZ and its derivatives, OXC, BIA 2-093 and BIA 2-024. The available data indicate that the anticonvulsant efficacy of these AEDs is mainly due to the inhibition of sodium channel activity.
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Affiliation(s)
- António F Ambrósio
- Department of Cell Biology, Center for Neuroscience of Coimbra, Portugal
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Yoshimura R, Nakamura J, Eto S, Ueda N. Possible relationships between plasma carbamazepine-10,11-epoxide levels and antimanic efficacy and side effects in patients with schizoaffective disorde. Hum Psychopharmacol 2000; 15:237-240. [PMID: 12404318 DOI: 10.1002/1099-1077(200006)15:4<237::aid-hup160>3.0.co;2-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We examined the relationships of plasma levels of carbamazepine (CBZ) and its two major metabolites, carbamazepine-10,11-epoxide (CBZ-E) and carbamazepine-10,11-diol (CBZ-D), with antimanic efficacy and side effects in patients with schizoaffective disorder. Positive relationships were found among plasma concentrations of CBZ-E and the degree of clinical improvement and side effects, whereas neither plasma CBZ nor CBZ-D levels were correlated with the degree of clinical improvement or side effects. Copyright 2000 John Wiley & Sons, Ltd.
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Affiliation(s)
- Reiji Yoshimura
- Department of Psychiatry, School of Medicine, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
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Ambrósio AF, Silva AP, Malva JO, Soares-da-Silva P, Carvalho AP, Carvalho CM. Carbamazepine inhibits L-type Ca2+ channels in cultured rat hippocampal neurons stimulated with glutamate receptor agonists. Neuropharmacology 1999; 38:1349-59. [PMID: 10471089 DOI: 10.1016/s0028-3908(99)00058-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In order to better understand the mechanism(s) of action of carbamazepine (CBZ), we studied its effects on the increase in [Ca2+]i and [Na+]i stimulated by glutamate ionotropic receptor agonists, in cultured rat hippocampal neurons, as followed by indo- or SBFI fluorescence, respectively. CBZ inhibited the increase in [Ca2+]i stimulated either by glutamate, kainate, alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionate (AMPA), or N-methyl-D-aspartate (NMDA), in a concentration-dependent manner. In order to discriminate the effects of CBZ on the activation of glutamate receptors from possible effects on Ca2+ channels, we determined the inhibitory effects of Ca2+ channel blockers on [Ca2+]i changes in the absence or in the presence of CBZ. The presence of 1 microM nitrendipine, 0.5 microM omega-conotoxin GVIA (omega-CgTx GVIA), or of both blockers, inhibited the kainate-stimulated increase in [Ca2+]i by 51.6, 32.9 or 68.7%, respectively. In the presence of both 100 microM CBZ and nitrendipine, the inhibition was similar (54.1%) to that obtained with nitrendipine alone, but in the presence of both CBZ and omega-CgTx GVIA, the inhibition was greater (54%) than that caused by omega-CgTx GVIA alone. However, CBZ did not inhibit the increase in [Na+]i stimulated by the glutamate receptor agonists, but inhibited the increase in [Na+]i due to veratridine. Tetrodotoxin, or MK-801, did not inhibit the influx of Na+ stimulated by kainate, indicating that Na+ influx occurs mainly through the glutamate ionotropic non-NMDA receptors. Moreover, LY 303070, a specific AMPA receptor antagonist, inhibited the [Na+]i response to kainate or AMPA by about 70 or 80%, respectively, suggesting that AMPA receptors are mainly involved. Taken together, the results suggest that CBZ inhibits L-type Ca2+ channels and Na+ channels, but does not inhibit activation of glutamate ionotropic receptors.
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Affiliation(s)
- A F Ambrósio
- Department of Cell Biology, Center for Neuroscience of Coimbra and Faculty of Medicine, University of Coimbra, Portugal
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