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Dhureja M, Chaturvedi P, Choudhary A, Kumar P, Munshi A. Molecular Insights of Drug Resistance in Epilepsy: Multi-omics Unveil. Mol Neurobiol 2024:10.1007/s12035-024-04220-6. [PMID: 38753128 DOI: 10.1007/s12035-024-04220-6] [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: 11/09/2023] [Accepted: 05/03/2024] [Indexed: 06/12/2024]
Abstract
Epilepsy is a devastating neurological disorder mainly associated with impaired synchronic discharge that leads to sensory, motor, and psychomotor impairments. Till now, about 30 anti-seizure medications (ASMs) have been approved for the management of epilepsy, yet one-third of individuals still have uncontrollable epilepsy and develop resistance. Drug resistance epilepsy (DRE) is defined as the condition where two ASMs fail to control the seizure in epileptic patients. The leading cause of the resistance was the extended use of ASMs. According to various studies, alterations in some genes and their expressions, along with specific metabolic impairments, are suggested to be associated with ASMs resistance and DRE pathophysiology. Several factors aid in the pathophysiology of DRE, such as alterations in protein-encoding genes such as neurotransmitter receptors, drug transporters, ion channels, and drug targets. Furthermore, the altered metabolite levels of metabolites implicated in neurotransmitter signaling, energetic pathways, oxidative stress, and neuroinflammatory signaling differentiate the epileptic patient from the DRE patient. Various DRE biomarkers can be identified using the "integrated omics approach," which includes the study of genomics, transcriptomics, and metabolomics. The current review has been compiled to understand the pathophysiological mechanisms of DRE by focusing on genomics, transcriptomics, and metabolomics. An effort has also been made to identify the therapeutic targets based on identifying significant markers by a multi-omics approach. This has the potential to develop novel therapeutic interventions in the future.
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Affiliation(s)
- Maanvi Dhureja
- Department of Pharmacology, Central University of Punjab, Bathinda, India
| | - Pragya Chaturvedi
- Department of Human Genetics and Molecular Medicines, Central University of Punjab, Bathinda, India
| | - Anita Choudhary
- Department of Human Genetics and Molecular Medicines, Central University of Punjab, Bathinda, India
| | - Puneet Kumar
- Department of Pharmacology, Central University of Punjab, Bathinda, India.
| | - Anjana Munshi
- Department of Human Genetics and Molecular Medicines, Central University of Punjab, Bathinda, India.
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Sahu R, Shah K. Schiff Bases: A Captivating Scaffold with Potential Anticonvulsant Activity. Mini Rev Med Chem 2024; 24:1632-1650. [PMID: 38629363 DOI: 10.2174/0113895575302197240408121537] [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: 01/03/2024] [Revised: 03/14/2024] [Accepted: 03/24/2024] [Indexed: 08/28/2024]
Abstract
One of the most important organic compounds, also known as a Schiff base, imine, or azomethine, has been associated with several biological processes. The group is a component of both natural or synthetic chemicals and functions as both a precursor and an intermediary in the synthesis of therapeutically active substances. The review highlights the various non-metal Schiff bases' structure-activity relationship (SAR) studies, general model, docking, and design approach for anticonvulsant actions. Schiff bases serve as linkers in numerous synthetic compounds with a variety of activities, according to the findings of several investigations. As a result, the current review will give readers a thorough understanding of the key ideas put forth by different researchers regarding the anticonvulsant properties of Schiff bases. It will serve as a valuable information source for those planning to synthesize new anticonvulsant molecules that contain Schiff bases as pharmacophores or biologically active moieties.
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Affiliation(s)
- Rakesh Sahu
- Department of Pharmaceutical Chemistry, School of Medical and Allied Sciences, Galgotias University, Greater Noida-201310, India
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Research, GLA University, Mathura 281406, India
| | - Kamal Shah
- Department of Pharmaceutical Chemistry, Institute of Pharmaceutical Research, GLA University, Mathura 281406, India
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3
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Characterization of monoaminergic neurochemicals in cortex and striatum of mouse brain. J Pharm Biomed Anal 2022; 217:114844. [DOI: 10.1016/j.jpba.2022.114844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/20/2022] [Accepted: 05/16/2022] [Indexed: 11/20/2022]
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Olubodun‐Obadun TG, Ishola IO, Ben‐Azu B, Afolayan O, Nwose E, James AB, Ajayi AM, Umukoro S, Adeyemi OO. Probable mechanisms involved in the antiepileptic activity of
Clerodendrum polycephalum
Baker (Labiatae) leaf extract in mice exposed to chemical‐induced seizures. J Food Biochem 2022; 46:e14342. [DOI: 10.1111/jfbc.14342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 06/17/2022] [Accepted: 06/27/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Taiwo G. Olubodun‐Obadun
- Department of Pharmacology, Therapeutics and Toxicology, Faculty of Basic Medical Sciences, College of Medicine University of Lagos Lagos Nigeria
| | - Ismail O. Ishola
- Department of Pharmacology, Therapeutics and Toxicology, Faculty of Basic Medical Sciences, College of Medicine University of Lagos Lagos Nigeria
| | - Benneth Ben‐Azu
- Neuropharmacology Unit, Department of Pharmacology and Therapeutics, College of Medicine University of Ibadan Ibadan Nigeria
- Department of Pharmacology, Faculty of Basic Medical Sciences, College of Medicine Delta State University Abraka Nigeria
| | - Olasunmbo Afolayan
- Department of Anatomy, Faculty of Basic Medical Sciences, College of Medicine University of Lagos Abraka Nigeria
| | - Ekene Nwose
- Department of Pharmacology, Therapeutics and Toxicology, Faculty of Basic Medical Sciences, College of Medicine University of Lagos Lagos Nigeria
| | - Ayorinde B. James
- Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine University of Lagos Lagos Nigeria
| | - Abayomi M. Ajayi
- Department of Pharmacology, Faculty of Basic Medical Sciences, College of Medicine Delta State University Abraka Nigeria
| | - Solomon Umukoro
- Department of Pharmacology, Faculty of Basic Medical Sciences, College of Medicine Delta State University Abraka Nigeria
| | - Olufunmilayo O. Adeyemi
- Department of Pharmacology, Therapeutics and Toxicology, Faculty of Basic Medical Sciences, College of Medicine University of Lagos Lagos Nigeria
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Kim SS, Kan H, Hwang KS, Yang JY, Son Y, Shin DS, Lee BH, Ahn SH, Ahn JH, Cho SH, Bae MA. Neurochemical Effects of 4-(2Chloro-4-Fluorobenzyl)-3-(2-Thienyl)-1,2,4-Oxadiazol-5(4H)-One in the Pentylenetetrazole (PTZ)-Induced Epileptic Seizure Zebrafish Model. Int J Mol Sci 2021; 22:1285. [PMID: 33525453 PMCID: PMC7865321 DOI: 10.3390/ijms22031285] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/18/2021] [Accepted: 01/26/2021] [Indexed: 01/03/2023] Open
Abstract
Epilepsy is one of the most common neurological disorders, and it is characterized by spontaneous seizures. In a previous study, we identified 4-(2-chloro-4-fluorobenzyl)-3-(2-thienyl)-1,2,4-oxadiazol-5(4H)-one (GM-90432) as a novel anti-epileptic agent in chemically- or genetically-induced epileptic zebrafish and mouse models. In this study, we investigated the anti-epileptic effects of GM-90432 through neurochemical profiling-based approach to understand the neuroprotective mechanism in a pentylenetetrazole (PTZ)-induced epileptic seizure zebrafish model. GM-90432 effectively improved PTZ-induced epileptic behaviors via upregulation of 5-hydroxytryptamine, 17-β-estradiol, dihydrotestosterone, progesterone, 5α -dihydroprogesterone, and allopregnanolone levels, and downregulation of normetanephrine, gamma-aminobutyric acid, and cortisol levels in brain tissue. GM-90432 also had a protective effect against PTZ-induced oxidative stress and zebrafish death, suggesting that it exhibits biphasic neuroprotective effects via scavenging of reactive oxygen species and anti-epileptic activities in a zebrafish model. In conclusion, our results suggest that neurochemical profiling study could be used to better understand of anti-epileptic mechanism of GM-90432, potentially leading to new drug discovery and development of anti-seizure agents.
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Affiliation(s)
- Seong Soon Kim
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
| | - Hyemin Kan
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
| | - Kyu-Seok Hwang
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
| | - Jung Yoon Yang
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
| | - Yuji Son
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
| | - Dae-Seop Shin
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
| | - Byung Hoi Lee
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
| | - Se Hwan Ahn
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (S.H.A.); (J.H.A.)
| | - Jin Hee Ahn
- Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Korea; (S.H.A.); (J.H.A.)
| | - Sung-Hee Cho
- Chemical Analysis Center, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea
| | - Myung Ae Bae
- Bio & Drug Discovery Division, Korea Research Institute of Chemical Technology, Daejeon 34114, Korea; (S.S.K.); (H.K.); (K.-S.H.); (J.Y.Y.); (Y.S.); (D.-S.S.); (B.H.L.)
- Department of Medicinal Chemistry and Pharmacology, University of Science & Technology, Daejeon 34113, Korea
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Stachowicz-Stencel T, Synakiewicz A. Biomarkers for pediatric cancer detection: latest advances and future perspectives. Biomark Med 2020; 14:391-400. [PMID: 32270691 DOI: 10.2217/bmm-2019-0613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cancer is one of the major health problems of the modern world. With the development of novel biochemistry and analytical instrumentation, precancer diagnosis has become a major focus of clinical and preclinical research. Finding appropriate biomarkers is crucial to make an early diagnosis, before the disease fully develops. With the improvement of precancer studies, cancer biomarkers prove their usefulness in providing important data on the cancer type and the status of patients' progression at a very early stage of the disease. Due to the constant evolution of pediatric cancer diagnosis, which includes highly advanced molecular techniques, the authors have decided to focus on selected groups of neoplastic disease and these include brain tumors, neuroblastoma, osteosarcoma and Hodgkin lymphoma.
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Affiliation(s)
- Teresa Stachowicz-Stencel
- Department of Pediatrics, Hematology & Oncology, Medical University of Gdansk, Poland 7 Debinki Street, 80-952 Gdansk, Poland
| | - Anna Synakiewicz
- Department of Pediatrics, Hematology & Oncology, Medical University of Gdansk, Poland 7 Debinki Street, 80-952 Gdansk, Poland
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Erdogan MA, Yusuf D, Erdogan A, Erbas O. Levodropropizine suppresses seizure activity in rats with pentylenetetrazol-induced epilepsy. Epilepsy Res 2018; 150:32-37. [PMID: 30610970 DOI: 10.1016/j.eplepsyres.2018.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 12/03/2018] [Accepted: 12/28/2018] [Indexed: 02/06/2023]
Abstract
BACKGROUND Millions of individuals worldwide suffer from epilepsy, and up to 25% of patients have seizures that are resistant to currently available antiepileptic drugs. Hence, there continues to be a need for more seizure medications that are effective yet tolerable. Levodropropizine (LVDP) is an established antitussive drug that, based on preclinical data, may also have antiepileptic activity. METHODS We treated rats with either intraperitoneal (IP) LVDP at two different doses or placebo in randomized fashion and then exposed them to IP pentylenetetrazol (PTZ), a potent seizure-inducing compound. We measured the rats' subsequent seizure activity with electroencephalography (EEG), Racine's convulsion scale (RCS) and time to first myoclonic jerk (TFMJ) to determine whether LVDP has antiepileptic properties in our murine model for epilepsy. RESULTS When compared to placebo, LVDP at both doses significantly suppressed seizure activity. Mean EEG spike wave percentage score decreased from 76.8% (placebo) to 13.1% (lower dose) and 7.6% (higher dose, bothp < 0.0001). RCS decreased from a mean of 5.8 (placebo) to 1.83 (lower dose) and 1.16 (higher dose, both p < 0.05). TFMJ had increased from a mean of 65.1 s (placebo), to 247.3 s (lower dose) and 295.5 s (higher dose, both p < 0.0001). CONCLUSIONS Levodropropizine, a common antitussive drug, suppresses seizure activity in rats with PTZ-induced status epilepticus. Given the ongoing need to find effective therapies for refractory epilepsy, the possibility of using levodropropizine as an antiepilepticshould be further explored.
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Affiliation(s)
- Mumin Alper Erdogan
- Department of Physiology, Faculty of Medicine, Izmir Katip Celebi University, Izmir, Turkey.
| | - Dimas Yusuf
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Arife Erdogan
- Department of Emergency Medicine, Izmir Bozyaka Training and Research Hospital, Izmir, Turkey.
| | - Oytun Erbas
- Department of Physiology, Faculty of Medicine, Bilim University, Istanbul, Turkey.
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8
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Nkamguie Nkantchoua GC, Kameni Njapdounke JS, Jules Fifen J, Sotoing Taiwe G, Josiane Ojong L, Kavaye Kandeda A, Ngo Bum E. Anticonvulsant effects of Senna spectabilis on seizures induced by chemicals and maximal electroshock. JOURNAL OF ETHNOPHARMACOLOGY 2018; 212:18-28. [PMID: 28986332 DOI: 10.1016/j.jep.2017.09.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/26/2017] [Accepted: 09/29/2017] [Indexed: 06/07/2023]
Abstract
Senna spectabilis (Fabaceae) is one of the medicinal plants used in Cameroon by traditional healers to treat epilepsy, constipation, insomnia, anxiety. The present study aimed to investigate the anticonvulsant effects of Senna spectabilis decoction on seizures induced by maximal electroshock (MES), pentylenetetrazole (PTZ), pilocarpine (PC) and its possible action mechanisms in animal models using flumazenil (FLU), methyl-ß-carboline-3-carboxylate (BC) and bicuculline (BIC). Senna spectabilis decoction (106.5 and 213.0mg/kg) antagonized completely tonic-clonic hind limbs of mice induced by MES. The lowest plant dose (42.6mg/kg) provided 100% of protection against seizures induced by PTZ (70mg/kg). Administration of different doses of the plant decoction antagonized seizures induced by PC up to 75%, causing a dose dependent protection and reduced significantly the mortality rate induced by this convulsant. Both FLU and BC antagonize strongly the anticonvulsant effects of this plant and are unable to reverse totally diazepam or the plant decoction effects on inhibiting seizures. The animals did not present any sign of acute toxicity even at higher doses of the plant decoction. In conclusion, Senna spectabilis possesses an anticonvulsant activity. We showed that its decoction protects significantly mice against seizures induced by chemicals and MES, delays the onset time and reduces mortality rate in seizures-induced. It also appears that the oral administration of the decoction of S. spectabilis is more active than the intraperitoneal administration of the ethanolic extract on inhibiting seizures induced by MES and PTZ. Moreover, the plant decoction could interact with GABAA complex receptor probably on the GABA and benzodiazepines sites.
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Affiliation(s)
| | | | - Jean Jules Fifen
- Department of Physics, Faculty of Science, The University of Ngaoundere, Cameroon
| | - Germain Sotoing Taiwe
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, Cameroon
| | - Lucie Josiane Ojong
- Department of Biological Sciences, Faculty of Science, The University of Ngaoundere, Cameroon
| | - Antoine Kavaye Kandeda
- Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1, Cameroon
| | - Elisabeth Ngo Bum
- Department of Biological Sciences, Faculty of Science, The University of Ngaoundere, Cameroon
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Silwal AP, Yadav R, Sprague JE, Lu HP. Raman Spectroscopic Signature Markers of Dopamine-Human Dopamine Transporter Interaction in Living Cells. ACS Chem Neurosci 2017; 8:1510-1518. [PMID: 28375605 DOI: 10.1021/acschemneuro.7b00048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dopamine (DA) controls many psychological and behavioral activities in the central nervous system (CNS) through interactions with the human dopamine transporter (hDAT) and dopamine receptors. The roles of DA in the function of the CNS are affected by the targeted binding of drugs to hDAT; thus, hDAT plays a critical role in neurophysiology and neuropathophysiology. An effective experimental method is necessary to study the DA-hDAT interaction and effects of variety of drugs like psychostimulants and antidepressants that are dependent on this interaction. In searching for obtaining and identifying the Raman spectral signatures, we have used surface enhanced Raman scattering (SERS) spectroscopy to record SERS spectra from DA, human embryonic kidney 293 cells (HEK293), hDAT-HEK293, DA-HEK293, and DA-hDAT-HEK293. We have demonstrated a specific 2D-distribution SERS spectral analytical approach to analyze DA-hDAT interaction. Our study shows that the Raman modes at 807, 839, 1076, 1090, 1538, and 1665 cm-1 are related to DA-hDAT interaction, where Raman shifts at 807 and 1076 cm-1 are the signature markers for the bound state of DA to probe DA-hDAT interaction. On the basis of density function theory (DFT) calculation, Raman shift of the bound state of DA at 807 cm-1 is related to combination of bending modes α(C3-O10-H21), α(C2-O11-H22), α(C7-C8-H18), α(C6-C4-H13), α(C7-C8-H19), and α(C7-C8-N9), and Raman shift at 1076 cm-1 is related to combination of bending modes α(H19-N9-C8), γ(N9-H19), γ(C8-H19), γ(N9-H20), γ(C8-H18), and α(C7-C8-H18). These findings demonstrate that protein-ligand interactions can be confirmed by probing change in Raman shift of ligand molecules, which could be crucial to understanding molecular interactions between neurotransmitters and their receptors or transporters.
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Affiliation(s)
- Achut P. Silwal
- Department of Chemistry
and Center for Photochemical Sciences, Bowling Green State University, Bowling
Green, Ohio 43403, United States
| | - Rajeev Yadav
- Department of Chemistry
and Center for Photochemical Sciences, Bowling Green State University, Bowling
Green, Ohio 43403, United States
| | - Jon E. Sprague
- The Ohio Attorney General’s Center for the Future of Forensic Science, Bowling Green, Ohio 43403, United States
| | - H. Peter Lu
- Department of Chemistry
and Center for Photochemical Sciences, Bowling Green State University, Bowling
Green, Ohio 43403, United States
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Genetically epilepsy-prone rats (GEPRs) and DBA/2 mice: Two animal models of audiogenic reflex epilepsy for the evaluation of new generation AEDs. Epilepsy Behav 2017; 71:165-173. [PMID: 26254980 DOI: 10.1016/j.yebeh.2015.06.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 06/12/2015] [Accepted: 06/17/2015] [Indexed: 01/08/2023]
Abstract
This review summarizes the current knowledge about DBA/2 mice and genetically epilepsy-prone rats (GEPRs) and discusses the contribution of such animal models on the investigation of possible new therapeutic targets and new anticonvulsant compounds for the treatment of epilepsy. Also, possible chemical or physical agents acting as proconvulsant agents are described. Abnormal activities of enzymes involved in catecholamine and serotonin synthesis and metabolism were reported in these models, and as a result of all these abnormalities, seizure susceptibility in both animals is greatly affected by pharmacological manipulations of the brain levels of monoamines and, prevalently, serotonin. In addition, both genetic epileptic models permit the evaluation of pharmacodynamic and pharmacokinetic interactions among several drugs measuring plasma and/or brain level of each compound. Audiogenic models of epilepsy have been used not only for reflex epilepsy studies, but also as animal models of epileptogenesis. The seizure predisposition (epileptiform response to sound stimulation) and substantial characterization of behavioral, cellular, and molecular alterations in both acute and chronic (kindling) protocols potentiate the usefulness of these models in elucidating ictogenesis, epileptogenesis, and their mechanisms. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".
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Sadek B, Saad A, Sadeq A, Jalal F, Stark H. Histamine H3 receptor as a potential target for cognitive symptoms in neuropsychiatric diseases. Behav Brain Res 2016; 312:415-30. [PMID: 27363923 DOI: 10.1016/j.bbr.2016.06.051] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/22/2016] [Accepted: 06/26/2016] [Indexed: 01/27/2023]
Abstract
The potential contributions of the brain histaminergic system in neurodegenerative diseases, and the possiblity of histamine-targeting treatments is attracting considerable interests. The histamine H3 receptor (H3R) is expressed mainly in the central nervous system, and is, consequently, an attractive pharmacological target. Although recently described clinical trials have been disappointing in attention deficit hyperactivity disorder (ADHD) and schizophrenia (SCH), numerous H3R antagonists, including pitolisant, demonstrate potential in the treatment of narcolepsy, excessive daytime sleepiness associated with cognitive impairment, epilepsy, and Alzheimer's disease (AD). This review focuses on the recent preclinical as well as clinical results that support the relevance of H3R antagonists for the treatment of cognitive symptoms in neuropsychiatric diseases, namely AD, epilepsy and SCH. The review summarizes the role of histaminergic neurotransmission with focus on these brain disorders, as well as the effects of numerous H3R antagonists on animal models and humans.
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Affiliation(s)
- Bassem Sadek
- Department of Pharmacology & Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates.
| | - Ali Saad
- Department of Pharmacology & Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Adel Sadeq
- College of Pharmacy, Al Ain University of Science and Technology, Al Ain, United Arab Emirates
| | - Fakhreya Jalal
- Department of Pharmacology & Therapeutics, College of Medicine & Health Sciences, United Arab Emirates University, P.O. Box 17666, Al Ain, United Arab Emirates
| | - Holger Stark
- Institute of Pharmaceutical and Medicinal Chemistry, Heinrich Heine University, Universitaetsstr. 1, 40225 Düsseldorf, Germany
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Konieczna L, Roszkowska A, Niedźwiecki M, Bączek T. Hydrophilic interaction chromatography combined with dispersive liquid–liquid microextraction as a preconcentration tool for the simultaneous determination of the panel of underivatized neurotransmitters in human urine samples. J Chromatogr A 2016; 1431:111-121. [DOI: 10.1016/j.chroma.2015.12.062] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/10/2015] [Accepted: 12/20/2015] [Indexed: 01/01/2023]
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13
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Penmatsa A, Wang KH, Gouaux E. X-ray structure of dopamine transporter elucidates antidepressant mechanism. Nature 2013; 503:85-90. [PMID: 24037379 DOI: 10.1038/nature12533] [Citation(s) in RCA: 459] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 08/07/2013] [Indexed: 12/11/2022]
Abstract
Antidepressants targeting Na(+)/Cl(-)-coupled neurotransmitter uptake define a key therapeutic strategy to treat clinical depression and neuropathic pain. However, identifying the molecular interactions that underlie the pharmacological activity of these transport inhibitors, and thus the mechanism by which the inhibitors lead to increased synaptic neurotransmitter levels, has proven elusive. Here we present the crystal structure of the Drosophila melanogaster dopamine transporter at 3.0 Å resolution bound to the tricyclic antidepressant nortriptyline. The transporter is locked in an outward-open conformation with nortriptyline wedged between transmembrane helices 1, 3, 6 and 8, blocking the transporter from binding substrate and from isomerizing to an inward-facing conformation. Although the overall structure of the dopamine transporter is similar to that of its prokaryotic relative LeuT, there are multiple distinctions, including a kink in transmembrane helix 12 halfway across the membrane bilayer, a latch-like carboxy-terminal helix that caps the cytoplasmic gate, and a cholesterol molecule wedged within a groove formed by transmembrane helices 1a, 5 and 7. Taken together, the dopamine transporter structure reveals the molecular basis for antidepressant action on sodium-coupled neurotransmitter symporters and elucidates critical elements of eukaryotic transporter structure and modulation by lipids, thus expanding our understanding of the mechanism and regulation of neurotransmitter uptake at chemical synapses.
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Affiliation(s)
- Aravind Penmatsa
- 1] Vollum Institute, Oregon Health & Science University, 3181 South West Sam Jackson Park Road, Portland, Oregon 97239, USA [2]
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Schneider PG, Rodríguez de Lores Arnaiz G. Ketamine prevents seizures and reverses changes in muscarinic receptor induced by bicuculline in rats. Neurochem Int 2012; 62:258-64. [PMID: 23279735 DOI: 10.1016/j.neuint.2012.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 11/27/2012] [Accepted: 12/12/2012] [Indexed: 11/17/2022]
Abstract
The cholinergic system has been implicated in several experimental epilepsy models. In a previous study bicuculline (BIC), known to antagonize GABA-A postsynaptic receptor subtype, was administered to rats at subconvulsant (1mg/kg) and convulsant (7.5mg/kg) doses and quinuclidinyl benzilate ([(3)H]-QNB) binding to CNS membranes was determined. It was observed that ligand binding to cerebellum increases while it decreases in the case of hippocampus. Saturation binding curves showed that changes were due to the modification of receptor affinity for the ligand without alteration of binding site number. The purpose of this study was to assay muscarinic receptors employing other BIC dose (5mg/kg), which induces seizures and allows the analysis of a postseizure stage as well. To study further muscarinic receptor involvement in BIC induced seizures, KET was also employed since it is a well known anticonvulsant in some experimental models. The administration of BIC at 5mg/kg to rats produced a similar pattern of changes in [(3)H]-QNB binding to those recorded with 1.0 and 7.5mg/kg doses. Here again, changes were observed in receptor binding affinity without alteration in binding site number for cerebellum or hippocampus membranes. Pretreatment with KET (40 mg/kg) prevented BIC seizures and reverted [(3)H]-QNB binding changes induced by BIC administration. The single administration of KET invariably resulted in [(3)H]-QNB binding decrease to either cerebellar or hippocampal membranes. KET added in vitro decreased ligand binding likewise. Results of combined treatment with KET plus BIC are hardly attributable to the single reversion of BIC effect since KET alone invariably decreased ligand binding. It is suggested that besides alteration of cholinergic muscarinic receptor other(s) neurotransmitter system(s) may well also be involved.
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Affiliation(s)
- Patricia Graciela Schneider
- Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis", CONICET-UBA, Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121 Buenos Aires, Argentina.
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Ekimova IV, Nitsinskaya LE, Romanova IV, Pastukhov YF, Margulis BA, Guzhova IV. Exogenous protein Hsp70/Hsc70 can penetrate into brain structures and attenuate the severity of chemically-induced seizures. J Neurochem 2010; 115:1035-44. [DOI: 10.1111/j.1471-4159.2010.06989.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Determination of dansylated monoamine and amino acid neurotransmitters and their metabolites in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry. Anal Biochem 2009; 396:103-11. [PMID: 19751698 DOI: 10.1016/j.ab.2009.09.015] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Revised: 09/05/2009] [Accepted: 09/09/2009] [Indexed: 11/23/2022]
Abstract
The determination of neurotransmitters (NTs) and their metabolites facilitates better understanding of complex neurobiology in the central nervous system disorders and has expanding uses in many other fields. We present a liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) method for the quantification of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), norepinephrine (NE), vanillymandelic acid (VMA), 3-methoxy-4-hydroxy phenylglycol (MHPG), 5-hydroxytryptamine (5-HT), 5-hydroxyindole-3-acetic acid (5-HIAA), glutamate (Glu), and gamma-aminobutyric acid (GABA). The NTs and their metabolites were dansylated and analyzed by an LC gradient on a C18 column on-line with a tandem mass spectrometer. This method exhibited excellent linearity for all of the analytes with regression coefficients higher than 0.99. The lower limit of quantification (LLOQ) values for DA, DOPAC, HVA, NE, VMA, MHPG, 5-HT, 5-HIAA, Glu, and GABA were 0.57, 0.37, 0.35, 0.40, 0.35, 0.91, 0.27, 0.43, 0.65, and 1.62 pmol/ml, respectively. The precision results were expressed as coefficients of variation (CVs), ranging from 1.5% to 13.6% for intraassay and from 2.9% to 13.7% for the interassay. This novel LC-ESI/MS/MS approach is precise, highly sensitive, specific, and sufficiently simple. It can provide an alternative method for the quantification of the NTs and their metabolites in human plasma.
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Schneider PG, Rodríguez de Lores Arnaiz G. Convulsant bicuculline modifies CNS muscarinic receptor affinity. BMC Neurosci 2006; 7:32. [PMID: 16615872 PMCID: PMC1463000 DOI: 10.1186/1471-2202-7-32] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2005] [Accepted: 04/17/2006] [Indexed: 11/17/2022] Open
Abstract
Background Previous work from this laboratory has shown that the administration of the convulsant drug 3-mercaptopropionic acid (MP), a GAD inhibitor, modifies not only GABA synthesis but also binding of the antagonist [3H]-quinuclidinyl benzilate ([3H]-QNB) to central muscarinic receptors, an effect due to an increase in affinity without modifications in binding site number. The cholinergic system has been implicated in several experimental epilepsy models and the ability of acetylcholine to regulate neuronal excitability in the neocortex is well known. To study the potential relationship between GABAergic and cholinergic systems with seizure activity, we analyzed the muscarinic receptor after inducing seizure by bicuculline (BIC), known to antagonize the GABA-A postsynaptic receptor subtype. Results We analyzed binding of muscarinic antagonist [3H]-QNB to rat CNS membranes after i.p. administration of BIC at subconvulsant (1.0 mg/kg) and convulsant (7.5 mg/kg) doses. Subconvulsant BIC dose failed to develop seizures but produced binding alteration in the cerebellum and hippocampus with roughly 40% increase and 10% decrease, respectively. After convulsant BIC dose, which invariably led to generalized tonic-clonic seizures, binding increased 36% and 15% to cerebellar and striatal membranes respectively, but decreased 12% to hippocampal membranes. Kd value was accordingly modified: with the subconvulsant dose it decreased 27% in cerebellum whereas it increased 61% in hippocampus; with the convulsant dose, Kd value decreased 33% in cerebellum but increased 85% in hippocampus. No change in receptor number site was found, and Hill number was invariably close to unity. Conclusion Results indicate dissimilar central nervous system area susceptibility of muscarinic receptor to BIC. Ligand binding was modified not only by a convulsant BIC dose but also by a subconvulsant dose, indicating that changes are not attributable to the seizure process itself. Findings support the notion that the muscarinic receptors play a major role in experimental epilepsy and provide a new example of differential neuronal plasticity.
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Affiliation(s)
- Patricia G Schneider
- Instituto de Biología Celular y Neurociencias "Prof. E. De Robertis", Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121-Buenos Aires, Argentina
| | - Georgina Rodríguez de Lores Arnaiz
- Instituto de Biología Celular y Neurociencias "Prof. E. De Robertis", Facultad de Medicina, Universidad de Buenos Aires, Paraguay 2155, 1121-Buenos Aires, Argentina
- Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junin 956, 1121-Buenos Aires, Argentina
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Elisabetsky E, Costa-Campos L. The alkaloid alstonine: a review of its pharmacological properties. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2006; 3:39-48. [PMID: 16550222 PMCID: PMC1375234 DOI: 10.1093/ecam/nek011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Accepted: 12/26/2005] [Indexed: 11/26/2022]
Abstract
Indole compounds, related to the metabolism of tryptophan, constitute an extensive family, and are found in bacteria, plants and animals. Indolic compounds possess significant and complex physiological roles, and especially indole alkaloids have historically constituted a class of major importance in the development of new plant derived drugs. The indole alkaloid alstonine has been identified as the major component of a plant-based remedy, used in Nigeria to treat mental illnesses by traditional psychiatrists. Although it is certainly difficult to compare the very concept of mental disorders in different cultures, the traditional use of alstonine is remarkably compatible with its profile in experimental animals. Even though alstonine in mice models shows a psychopharmacological profile closer to the newer atypical antipsychotic agents, it also shows important differences and what seems to be an exclusive mechanism of action, not entirely clarified at this point. Considering the seemingly unique mode of action of alstonine and that its traditional use can be viewed as indicative of bioavailability and safety, this review focuses on the effects of alstonine in the central nervous system, particularly on its unique profile as an antipsychotic agent. We suggest that a thorough understanding of traditional medical concepts of health and disease in general and traditional medical practices in particular, can lead to true innovation in paradigms of drug action and development. Overall, the study of this unique indole alkaloid may be considered as another example of the richness of medicinal plants and traditional medical systems in the discovery of new prototypic drugs.
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Affiliation(s)
- E Elisabetsky
- Laboratório de Etnofarmacologia, ICBS, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Becker A, Schmitz M, Grecksch G. Kindling modifies morphine, cocaine and ethanol place preference. Exp Brain Res 2005; 168:33-40. [PMID: 16096784 DOI: 10.1007/s00221-005-0081-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Accepted: 06/08/2005] [Indexed: 11/24/2022]
Abstract
Brailowsky and Garcia (1999) proposed the existence of a relationship between epilepsy and addiction. To prove this hypothesis, pentylenetetrazol kindled rats were tested in the conditioned place preference (CPP) paradigm for their reaction to various addictive drugs with different modes of action (morphine, cocaine and ethanol). In separate experiments, locomotor activity and body temperature after application of the same drugs were tested in kindled and non-kindled rats. In the CPP experiment there were significant differences between both groups of rats. Non-kindled animals showed place preference to morphine (5.0 mg/kg) or cocaine (20.0 mg/kg). This reaction was abolished in the kindled rats. Moreover, control rats demonstrated aversion to 2.0 g/kg ethanol. However, ethanol aversion was not detectable in kindled rats. Moreover, there was no difference between non-kindled and kindled rats in locomotor activity and body temperature after morphine (1.0 and 5.0 mg/kg), cocaine (10.0 and 20.0 mg/kg), or ethanol (0.5 and 2.0 g/kg) application. This suggests alterations in reward systems as a consequence of kindling. It is hypothesised that GABAergic neurones in the ventral tegmental area might play a major role in the alterations found.
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Affiliation(s)
- Axel Becker
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, Faculty of Medicine, Leipziger Str. 44, 39120, Magdeburg, Germany.
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Gareri P, Condorelli D, Belluardo N, Russo E, Loiacono A, Barresi V, Trovato-Salinaro A, Trovato-Salinato A, Mirone MB, Ferreri Ibbadu G, De Sarro G. Anticonvulsant effects of carbenoxolone in genetically epilepsy prone rats (GEPRs). Neuropharmacology 2004; 47:1205-16. [PMID: 15567430 DOI: 10.1016/j.neuropharm.2004.08.021] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2004] [Revised: 07/14/2004] [Accepted: 08/18/2004] [Indexed: 11/29/2022]
Abstract
Carbenoxolone (CBX), the succinyl ester of glycyrrhetinic acid, is an inhibitor of gap junctional intercellular communication. Systemic administration of CBX was able to decrease the seizure severity score and to increase the latency time of seizure onset in genetically epilepsy prone rats (GEPRs). In particular, intravenous or intraperitoneal administration of carbenoxolone (5-30 mg/kg) produced a dose-dependent and significant reduction in the clonic and tonic phases of the audiogenic seizures in GEPRs. The anticonvulsant doses were not associated with an impairment of motor coordination. The bilateral microinjection of CBX (0.001-0.50 microg/0.5 microl) into the inferior colliculi, the substantia nigra (pars reticulata or compacta) and the inferior olivary complex was able to reduce the seizure severity score in a dose-dependent manner. The anticonvulsant effects were longer lasting after focal microinjection than after systemic administration. No anticonvulsant effects were observed following focal bilateral microinjections of glycyrrhizin into the same brain areas where CBX was shown to be effective.
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Affiliation(s)
- Pietro Gareri
- Section of Pharmacology, Department of Experimental and Clinical Medicine, Faculty of Medicine and Surgery, University of Catanzaro, 88100 Catanzaro, Italy
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22
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Hoogland G, Spierenburg HA, van Veelen CWM, van Rijen PC, van Huffelen AC, de Graan PNE. Synaptosomal glutamate and GABA transport in patients with temporal lobe epilepsy. J Neurosci Res 2004; 76:881-90. [PMID: 15160399 DOI: 10.1002/jnr.20128] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
High-affinity glutamate and GABA transporters found in the plasma membrane of neurons and glial cells terminate neurotransmission by rapidly removing extracellular transmitter. Impairment of transporter function has been implicated in the pathophysiologic mechanisms underlying epileptogenesis. We characterized glutamate and gamma-aminobutyric acid (GABA) transport in synaptosomes, isolated from neocortical and hippocampal biopsies of patients with temporal lobe epilepsy (TLE). We analyzed K(+)-evoked release in the presence and absence of Ca(2+) to determine vesicular and transporter-mediated release, respectively. We also analyzed (3)H-glutamate and (3)H-GABA uptake, the effect of glutamate uptake inhibitors L-trans-pyrrolidine-2,4-dicarboxylic acid (tPDC) and DL-threo-beta-benzyloxyaspartate (TBOA), and GABA uptake inhibitor N-(4,4-diphenyl-3-butenyl)-3-piperidinecarboxylic acid (SK&F 89976-A). Neocortical synaptosomes from TLE patients did not show vesicular glutamate release, strongly reduced transporter-mediated release, and an increased basal release compared to that in rat synaptosomes. Furthermore, basal release was less sensitive to tPDC, and (3)H-glutamate uptake was reduced compared to that in rat synaptosomes. Vesicular GABA release from neocortical synaptosomes of TLE patients was reduced compared to that in rat synaptosomes, whereas transporter-mediated release was hardly affected. Furthermore, basal GABA release was more than doubled, but neither basal nor stimulated release were increased by SK&F 89976-A, which did significantly increase both types of GABA release in rat synaptosomes. Finally, (3)H-GABA uptake by synaptosomes from TLE patients was reduced significantly in hippocampus (0.19 +/- 0.04%), compared to that in neocortex (0.32 +/- 0.04%). Control experiments with human peritumoral cortical tissue suggest that impaired uptake of glutamate, but not of GABA, was caused in part by the hypoxic state of the biopsy. Our findings provide evidence for impaired function of glutamate and GABA transporters in human TLE.
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Affiliation(s)
- G Hoogland
- Department of Pharmacology and Anatomy, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
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Jimenez EC, Donevan S, Walker C, Zhou LM, Nielsen J, Cruz LJ, Armstrong H, White HS, Olivera BM. Conantokin-L, a new NMDA receptor antagonist: determinants for anticonvulsant potency. Epilepsy Res 2002; 51:73-80. [PMID: 12350383 DOI: 10.1016/s0920-1211(02)00101-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Conantokins are N-methyl-D-aspartate receptor antagonist peptides found in the venoms of marine cone snails. Current intense interest in this peptide family stems from the discovery of their therapeutic potential as anticonvulsants. It was recently reported that conantokin-R is a highly potent anticonvulsant compound, with a protective index of 17.5 when tested in the audiogenic mouse model of epilepsy. Conantokin-L was characterized from Conus lynceus and found to have extensive homology with conantokin-R, except For the C-terminal amino acids. Although conantokin-L appears almost as potent as conantokin-R in standard in vivo assays for conantokins and NMDA receptor binding assays, it is far less potent as an anticonvulsant, with a protective index of 1.2 in the audiogenic mouse model. The results suggest that the C-terminal sequences of conantokin-R and conantokin-L are a major determinant of their anticonvulsant potency.
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Affiliation(s)
- Elsie C Jimenez
- Department of Biology, University of Utah, 257 South 1400 East #201, Salt Lake City, UT 84112-0840, USA
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Kasture VS, Deshmukh VK, Chopde CT. Anxiolytic and anticonvulsive activity of Sesbania grandiflora leaves in experimental animals. Phytother Res 2002; 16:455-60. [PMID: 12203267 DOI: 10.1002/ptr.971] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Various parts of Sesbania grandiflora have been used in the Indian system of medicine, in particular, the leaves of S. grandiflora are used in Ayurveda for the treatment of epileptic fits. In the present study we have evaluated the anticonvulsive activity of S. grandiflora leaves using a variety of animal models of convulsions. Bioassay guided separation was also carried out to identify the fraction possessing anticonvulsant activity. The benzene:ethyl acetate fraction (BE) of the acetone soluble part of a petroleum ether extract significantly delayed the onset of convulsions in pentylenetetrazol (PTZ) and strychnine (STR)- induced seizures in mice and reduced the duration of tonic hindleg extension in the maximum electroconvulsive shock (MES) induced seizures in mice. The BE contained a triterpene as a major component. In addition, the BE also inhibited electrically induced kindled seizures in mice and lithium-pilocarpine-induced status epilepticus in rats. It prolonged the duration of sleep induced by pentobarbital and antagonized the effect of D-amphetamine. Mice treated with BE preferred to remain in the open arm of the elevated plus maze indicating anxiolytic activity. The BE raised the brain contents of gamma-aminobutyric acid and serotonin. Thus the triterpene containing fraction of S. grandiflora exhibits a wide spectrum of anticonvulsant profile and anxiolytic activity.
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25
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Ferraz AC, Anselmo-Franci JA, Perosa SR, de Castro-Neto EF, Bellissimo MI, de Oliveira BH, Cavalheiro EA, Naffah-Mazzacoratti MDG, Da Cunha C. Amino acid and monoamine alterations in the cerebral cortex and hippocampus of mice submitted to ricinine-induced seizures. Pharmacol Biochem Behav 2002; 72:779-86. [PMID: 12062566 DOI: 10.1016/s0091-3057(02)00750-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The alkaloid ricinine isolated from the plant Ricinus communis, when administered to mice at high doses, induces clonic seizures accompanied by electroencephalographic alterations in the cerebral cortex and hippocampus. The lethal nature of ricinine-induced seizures is considered to be a good model for the study of the events that cause death during clonic seizures, particularly those related to respiratory spasms. The initial signs (pre-seizure period) were marked by exophthalmus and decreased locomotor behavior. Animals killed during the preseizure period presented an increased utilization rate (HVA/DA) of dopamine (DA), an increased concentration of noradrenaline (NA), and a decreased concentration of glutamate (Glu), glutamine (Gln), taurine (Tau), and serotonin (5-HT) in the cerebral cortex. The seizure period is characterized by the occurrence of hind limb myoclonus and respiratory spasms, which are followed by death. Alterations in the cerebral cortex concentration of these neurotransmitters persisted during the seizure period. These alterations are only partially observed in the hippocampus, mainly during the seizure period. The present results suggest that an increased release of Glu in the cerebral cortex can be implicated in the genesis of the ricinine-induced seizure and that it triggers many anticonvulsive mechanisms, like the release of Tau, DA, 5-HT, and NA.
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Affiliation(s)
- Anete C Ferraz
- Laboratório de Fisiologia e Farmacologia do SNC, Departamento de Fisiologia e Departamento de Farmacologia, Universidade Federal do Paraná, Curitiba, PR, Brazil
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26
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de Mello CF, Kölker S, Ahlemeyer B, de Souza FR, Fighera MR, Mayatepek E, Krieglstein J, Hoffmann GF, Wajner M. Intrastriatal administration of 3-hydroxyglutaric acid induces convulsions and striatal lesions in rats. Brain Res 2001; 916:70-5. [PMID: 11597592 DOI: 10.1016/s0006-8993(01)02865-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Glutaryl-CoA dehydrogenase deficiency is an inherited neurometabolic disease complicated by precipitation of acute encephalopathic crises during a vulnerable period of brain development. These crises result in bilateral striatal damage and subsequently a dystonic dyskinetic movement disorder. In previous in vitro studies neuronal damage in this disease has been linked to an excitotoxic mechanism mediated in particular by one of the accumulating metabolites, 3-hydroxyglutaric acid. However, nothing is known about the in vivo effects of this organic acid. In the present study, we used a stereotaxic intrastriatal injection technique to investigate the behavioral and neurotoxic effects of 3-hydroxyglutaric acid exposure in rats. Here, we report that 3-hydroxyglutaric acid induced an increase in convulsion frequency and duration as determined by open field measurement. Nissl-stained coronal sections from treated rats revealed a pale lesion in the striatum following 3-hydroxyglutaric acid exposure. N-methyl-D-aspartate (NMDA) receptor blockade by MK-801 and stimulation of GABA(A) receptors by muscimol prevented the induction of convulsions and striatal damage by 3-hydroxyglutaric acid, whereas blockade of non-NMDA receptors by 6,7-dinitroquinoxaline-2,3-dione (DNQX) was not protective. We conclude that 3-hydroxyglutaric acid induces convulsions and striatal damage via initiation of an imbalance in the excitatory glutamatergic and the inhibitory GABAergic neurotransmission, resulting in an enhanced excitatory input in striatal neurons. These results support the hypothesis of NMDA receptor-mediated excitotoxic cell damage in glutaryl-CoA dehydrogenase deficiency and represent the basis for the development of new neuroprotective treatment strategies.
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MESH Headings
- Acyl Coenzyme A/deficiency
- Animals
- Brain Diseases, Metabolic, Inborn/metabolism
- Brain Diseases, Metabolic, Inborn/pathology
- Brain Diseases, Metabolic, Inborn/physiopathology
- Excitatory Amino Acid Antagonists/pharmacology
- GABA Agonists/pharmacology
- GABA-A Receptor Agonists
- Glutamic Acid/metabolism
- Glutarates/toxicity
- Male
- Neostriatum/drug effects
- Neostriatum/pathology
- Neostriatum/physiopathology
- Neurotoxins/toxicity
- Rats
- Rats, Wistar
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/metabolism
- Receptors, GABA-A/metabolism
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/metabolism
- Seizures/chemically induced
- Seizures/pathology
- Seizures/physiopathology
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Affiliation(s)
- C F de Mello
- Department of Chemistry, University of Santa Maria, Santa Maria, Brazil
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Mafra RA, Araújo DA, Beirão PS, Cruz JS. Glutamate transport in rat cerebellar granule cells is impaired by inorganic epileptogenic agents. Neurosci Lett 2001; 310:85-8. [PMID: 11585573 DOI: 10.1016/s0304-3940(01)02069-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
There is evidence that extracellular glutamate levels are elevated in certain brain regions immediately prior to and during induction and propagation of seizures. There appears to be a correlation between the capacity of removing released glutamate and the genesis of epileptiform activity. Some models make use of metals, such as Co(2+) and Ni(2+), to induce epilepsy. We used patch-clamp recordings to measure the electrogenic glutamate transport in neuronal cells. The present results indicate that Co(2+) (1 mM) and Ni(2+) (5 mM) blocked glutamate transport by 17.6+/-3.9% (n=5, P<0.05) and by 31.8+/-6.2% (n=7, P<0.05), respectively. Ni(2+) inhibited glutamate uptake in a dose-dependent manner. The IC(50) value obtained was 66.6 microM and the maximum inhibition was 40%. We conclude that one mechanism that may explain the seizures induced by exposure to those divalent cations is inhibition of the glutamate transporter.
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Affiliation(s)
- R A Mafra
- Departamento de Fisiologia, CCBI, Universidade Federal de Alagoas, Maceió-AL, Brazil
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Stokes AH, Bernard LP, Nicklas WJ, Zeevalk GD. Attenuation of malonate toxicity in primary mesencephalic cultures using the GABA transport blocker, NO-711. J Neurosci Res 2001; 64:43-52. [PMID: 11276050 DOI: 10.1002/jnr.1052] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Cultured rat mesencephalic neurons were used to assess the effects of gamma-aminobutyric acid (GABA) transport blockers on toxicity caused by malonate, a reversible, competitive inhibitor of succinate dehydrogenase. Previous studies utilizing an ex vivo chick retinal preparation have shown that GABA release and cell swelling are early consequences of acute energy impairment and that GABA transport blockers attenuate this toxicity. The present results demonstrate that the nonsubstrate GABA transport blocker, NO-711 (1 nM-1 microM), dose-dependently protected cultured mesencephalic dopamine (DA) and GABA neurons from malonate-induced toxicity. Similar protection was demonstrated with nipecotic acid (1 mM) and SKF89976A (100 nM), substrate and nonsubstrate GABA transport blockers, respectively. These compounds by themselves produced no signs of toxicity, although nipecotic acid caused a long-term decrease in GABA uptake not associated with toxicity. Compounds which decrease intracellular reactive oxygen species (ROS) are protective in this model, but NO-711 did not prevent the rise in intracellular ROS induced by malonate, indicating its protective effects were downstream of ROS production. Supplementation of malonate treated cultures with the GABA(A) agonist, muscimol (10 microM), increased the toxicity toward the DA and GABA neuron populations. Antagonists at the GABA(A) and glycine receptors provided partial protection to both the GABA and DA neurons. These findings suggest that the GABA transporter, GABA(A), and/or glycine channels contribute to cell damage associated with energy impairment in this model.
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Affiliation(s)
- A H Stokes
- Department of Neurology, Robert Wood Johnson Medical School-UMDNJ, 675 Hoes Lane, Piscataway, NJ 08854, USA
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Abstract
In the past decade, nine new drugs have been licensed for the treatment of epilepsy. With limited clinical experience of these agents, the mechanisms of action of antiepileptic drugs may be an important criterion in the selection of the most suitable treatment regimens for individual patients. At the cellular level, three basic mechanisms are recognised: modulation of voltage-dependent ion channels, enhancement of inhibitory neurotransmission, and attenuation of excitatory transmission. In this review, we will attempt to introduce the concepts of ion channel and neurotransmitter modulation and, thereafter, group currently used antiepileptic drugs according to their principal mechanisms of action.
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Affiliation(s)
- P Kwan
- Epilepsy Unit, University Department of Medicine and Therapeutics, Western Infirmary, Glasgow G11 6NT, Scotland, UK
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Coitinho AS, de Mello CF, Lima TT, de Bastiani J, Fighera MR, Wajner M. Pharmacological evidence that alpha-ketoisovaleric acid induces convulsions through GABAergic and glutamatergic mechanisms in rats. Brain Res 2001; 894:68-73. [PMID: 11245816 DOI: 10.1016/s0006-8993(00)03321-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Neurological dysfunction is common in patients with maple syrup urine disease (MSUD). However, the mechanisms underlying the pathophysiology of this disorder are poorly known. In the present study we investigated the effect of intrastriatal administration of the alpha-keto acids accumulating in MSUD on the behavior of adult rats. After cannula placing, rats received unilateral intrastriatal injections of alpha-ketoisocaproic acid (KIC, 8 micromol), alpha-ketoisovaleric acid (KIV, 8 micromol), alpha-keto-beta-methylvaleric acid (KMV, 6 micromol) or NaCl. KIV elicited clonic convulsions in a dose-response manner, whereas KIC and KMV did not induce seizure-like behavior. Convulsions provoked by KIV were prevented by intrastriatal preadministration of muscimol (46 pmol) and MK-801 (3 nmol), but not by the preadministration of DNQX (8 nmol). These results indicate that among the keto acids that accumulate in MSUD, KIV is the only metabolite capable of causing convulsions in the present animal model and indicates that KIV is an important excitatory metabolite. Moreover, the participation of GABAergic and glutamatergic NMDA mechanisms in the KIV-induced convulsant behavior is suggested, since KIV-induced convulsions are attenuated by muscimol and MK-801. The authors suggest that KIV may play an important role in the convulsions observed in MSUD, and highlight its relevance to the understanding of the pathophysiology of the neurological dysfunction of MSUD patients.
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Affiliation(s)
- A S Coitinho
- Universidade Federal do Rio Grande do Sul, Instituto de Ciências Básicas da Saúde, Departamento de Bioquímica, Rua Ramiro Barcelos 2600, RS 90035-003, Porto Alegre, Brazil
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31
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Peña F, Tapia R. Seizures and neurodegeneration induced by 4-aminopyridine in rat hippocampus in vivo: role of glutamate- and GABA-mediated neurotransmission and of ion channels. Neuroscience 2001; 101:547-61. [PMID: 11113304 DOI: 10.1016/s0306-4522(00)00400-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Infusion of the K(+) channel blocker 4-aminopyridine in the hippocampus induces the release of glutamate, as well as seizures and neurodegeneration. Since an imbalance between excitation and inhibition, as well as alterations of ion channels, may be involved in these effects of 4-aminopyridine, we have studied whether they are modified by drugs that block glutamatergic transmission or ion channels, or drugs that potentiate GABA-mediated transmission. The drugs were administered to anesthetized rats subjected to intrahippocampal infusion of 4-aminopyridine through microdialysis probes, with simultaneous collection of dialysis perfusates and recording of the electroencephalogram, and subsequent histological analysis. Ionotropic glutamate receptor antagonists clearly diminished the intensity of seizures and prevented the neuronal damage, but did not alter substantially the enhancement of extracellular glutamate induced by 4-aminopyridine. None of the drugs facilitating GABA-mediated transmission, including uptake blockers, GABA-transaminase inhibitors and agonists of the A-type receptor, was able to reduce the glutamate release, seizures or neuronal damage produced by 4-aminopyridine. In contrast, nipecotate, which notably increased extracellular levels of the amino acid, potentiated the intensity of seizures and the neurodegeneration. GABA(A) receptor antagonists partially reduced the extracellular accumulation of glutamate induced by 4-aminopyridine, but did not exert any protective action. Tetrodotoxin largely prevented the increase of extracellular glutamate, the electroencephalographic epileptic discharges and the neuronal death in the CA1 and CA3 hippocampal regions. Valproate and carbamazepine, also Na(+) channel blockers that possess general anticonvulsant action, failed to modify the three effects of 4-aminopyridine studied. The N-type Ca(2+) channel blocker omega-conotoxin, the K(+) channel opener diazoxide, and the non-specific ion channel blocker riluzole diminished the enhancement of extracellular glutamate and slightly protected against the neurodegeneration. However, the two former compounds did not antagonize the 4-aminopyridine-induced epileptiform discharges, and riluzole instead markedly increased the intensity and duration of the disharges. Moreover, at the highest dose tested (8mg/kg, i.p.), riluzole caused a 75% mortality of the rats. We conclude that 4-aminopyridine stimulates the release of glutamate from nerve endings and that the resultant augmented extracellular glutamate is directly related to the neurodegeneration and is involved in the generation of epileptiform discharges through the concomitant overactivation of glutamate receptors. Under these conditions, a facilitated GABA-mediated transmission may paradoxically boost neuronal hyperexcitation. Riluzole, a drug used to treat amyotrophic lateral sclerosis, seems to be toxic when combined with neuronal hyperexcitation.
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Affiliation(s)
- F Peña
- Departamento de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP 70-253, 04510, D.F., Mexico City, Mexico
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Kwan P, Sills GJ, Kelly K, Butler E, Brodie MJ. Glutamic acid decarboxylase autoantibodies in controlled and uncontrolled epilepsy: a pilot study. Epilepsy Res 2000; 42:191-5. [PMID: 11074191 DOI: 10.1016/s0920-1211(00)00180-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
There have been anecdotal reports of raised glutamic acid decarboxylase (GAD) autoantibodies in patients with refractory epilepsy. We measured serum GAD autoantibodies in 105 patients with idiopathic or symptomatic epilepsy. There was no significant difference in the absolute titre of GAD autoantibody between patients with controlled and uncontrolled epilepsy. However, four female patients with uncontrolled epilepsy had levels that were over three times above the highest detected in the seizure-free group, three of whom also tested positive for pancreatic islet cell antibodies. Larger scale studies, perhaps comparing different epilepsy syndromes, are required to determine the exact clinical role of GAD autoantibodies in epilepsy.
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Affiliation(s)
- P Kwan
- Epilepsy Unit, Department of Medicine and Therapeutics, Western Infirmary, Glasgow G11 6NT, Scotland, UK
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Leal MB, de Souza DO, Elisabetsky E. Long-lasting ibogaine protection against NMDA-induced convulsions in mice. Neurochem Res 2000; 25:1083-7. [PMID: 11055745 DOI: 10.1023/a:1007665911622] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Ibogaine, a putative antiaddictive drug, is remarkable in its apparent ability to downgrade withdrawal symptoms and drug craving for extended periods of time after a single dose. Ibogaine acts as a non-competitive NMDA receptor antagonist, while NMDA has been implicated in long lasting changes in neuronal function and in the physiological basis of drug addiction. The purpose of this study was to verify if persistent changes in NMDA receptors could be shown in vivo and in vitro after a single administration of ibogaine. The time course of ibogaine effects were examined on NMDA-induced seizures and [3H] MK-801 binding to cortical membranes in mice 30 min, 24, 48, and 72 h post treatment. Ibogaine (80 mg/kg, ip) was effective in inhibiting convulsions induced by NMDA at 24 and 72 hours post administration. Likewise, [3H] MK-801 binding was significantly decreased at 24 and 72 h post ibogaine. No significant differences from controls were found at 30 min or 48 h post ibogaine. This long lasting and complex pattern of modulation of NMDA receptors prompted by a single dose of ibogaine may be associated to its antiaddictive properties.
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Affiliation(s)
- M B Leal
- Departamento de Farmacologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Emanuelli T, Prauchner CA, Dacanal J, Zeni A, Reis EC, de Mello CF, de Souza DO. Intrastriatal administration of 5-aminolevulinic acid induces convulsions and body asymmetry through glutamatergic mechanisms. Brain Res 2000; 868:88-94. [PMID: 10841891 DOI: 10.1016/s0006-8993(00)02327-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The involvement of glutamatergic and GABAergic mechanisms in the behavioral effects induced by the intrastriatal injection of 5-aminolevulinic acid (ALA) (1-8 mgr;mol/2 mgr;l), a metabolite that accumulates in porphyrias, was evaluated. ALA administration to adult female rats increased locomotor activity, induced clonic convulsions and elicited dose-dependent body asymmetry assessed by the elevated body swing test. ALA-induced convulsions were prevented by intrastriatal preadministration of the glutamate antagonists, 6, 7-dinitroquinoxaline-2,3-dione (8 nmol/0.5 microl) or dizocilpine (2. 5 nmol/0.5 microl), but not by the GABA agonist, muscimol (46 pmol/0. 5 microl). Body asymmetry was prevented only by 6, 7-dinitroquinoxaline-2,3-dione pretreatment. A higher dose of muscimol (92 pmol/0.5 microl) prevented both ALA-induced convulsions and body asymmetry. However, this dose of muscimol induced motor biases, which make difficult to ascertain the involvement of GABA(A) receptors in ALA-induced behavioral effects. This study suggests that glutamatergic mechanisms underlie the ALA-induced convulsions and body asymmetry. The present results may be of value in understanding the physiopathology of the neurological dysfunction occurring in acute porphyrias.
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Affiliation(s)
- T Emanuelli
- Departamento de Tecnologia e Ciência de Alimentos, Centro de Ciências Rurais, Universidade Federal de Santa Maria, Campus - Camobi, 97105-900, RS, Santa Maria, Brazil.
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Hoogland G, Hens JJ, De Wit M, van Veelen CW, van Huffelen AC, Gispen WH, de Graan PN. Glutamate and gamma-aminobutyric acid content and release of synaptosomes from temporal lobe epilepsy patients. J Neurosci Res 2000; 60:686-95. [PMID: 10820440 DOI: 10.1002/(sici)1097-4547(20000601)60:5<686::aid-jnr14>3.0.co;2-p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
During surgical intervention in medically refractory temporal lobe epilepsy (TLE) patients, diagnosed with either mesial temporal lobe sclerosis (MTS)- or tumor (T)-associated TLE, biopsies were taken from the anterior temporal neocortex and the hippocampal region. Synaptosomes, isolated from these biopsies were used to study intrasynaptosomal Ca(2+) levels ([Ca(2+)](i)), and glutamate and gamma-aminobutyric acid (GABA) contents and release. All synaptosomal preparations demonstrated a basal [Ca(2+)](i) of about 200 nM, except neocortical synaptosomes from MTS-associated TLE patients (420 nM). K(+)-induced depolarization resulted in a robust increase of the basal [Ca(2+)](i) in all preparations. Neocortical synaptosomes from TLE patients contained 22.9 +/- 3.0 nmol glutamate and 4.6 +/- 0.5 nmol GABA per milligram synaptosomal protein, whereas rat cortical synaptosomes contained twice as much glutamate and four times as much GABA. Hippocampal synaptosomes from MTS-associated TLE patients, unlike those from T-associated TLE patients, contained about 70% less glutamate and 55% less GABA than neocortical synaptosomes. Expressed as percentage of total synaptosomal content, synaptosomes from MTS-associated TLE patients exhibited an increased basal and a reduced K(+)-induced glutamate and GABA release compared to rat cortical synaptosomes. In MTS-associated TLE patients, only GABA release from neocortical synaptosomes was partially Ca(2+)-dependent. Control experiments in rat synaptosomes demonstrated that at least part of the reduction in K(+)-induced release can be ascribed to resection-induced hypoxia in biopsies. Thus, synaptosomes from MTS-associated TLE patients exhibit a significant K(+)-induced increase in [Ca(2+)](i), but the consequent release of glutamate and GABA is severely impaired. Our data show that at least part of the differences in glutamate and GABA content and release between human biopsy material and fresh rat tissue is due to the resection time.
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Affiliation(s)
- G Hoogland
- Rudolf Magnus Institute for Neurosciences, University Medical Center Utrecht, The Netherlands
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36
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Mußhoff U, Madeja M, Binding N, Witting U, Speckmann EJ. 2-Phenoxyethanol: a neurotoxicant? — Reply. Arch Toxicol 2000. [DOI: 10.1007/s002040000111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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De Sarro G, Gareri P, Falconi U, De Sarro A. 7-Nitroindazole potentiates the antiseizure activity of some anticonvulsants in DBA/2 mice. Eur J Pharmacol 2000; 394:275-88. [PMID: 10771293 DOI: 10.1016/s0014-2999(00)00086-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
7-Nitroindazole, a selective neuronal nitric oxide synthase inhibitor (25-200 mg kg(-1), intraperitoneally (i.p.)) antagonized audiogenic seizures in DBA/2 mice in a dose-dependent manner. We investigated the effects of 7-nitroindazole at a dose of 25 mg kg(-1) i.p., which per se did not show anticonvulsant activity against audiogenic seizures in DBA/2 mice, on the antiseizure activity of some conventional antiepileptic drugs. 7-Nitroindazole sometimes potentiated the anticonvulsant activity of carbamazepine, diazepam, lamotrigine, phenytoin, phenobarbital and valproate against audiogenic seizures in DBA/2 mice. The degree of potentiation by 7-nitroindazole was greatest for phenobarbital and diazepam, less for valproate and least for carbamazepine, lamotrigine and phenytoin. The increase in anticonvulsant activity was associated with a comparable increase in motor impairment. However, the therapeutic index of combined treatment with diazepam+7-nitroindazole, phenobarbital+7-nitroindazole or valproate+7-nitroindazole was more favourable than that of the diazepam+vehicle, phenobarbital+vehicle or valproate+vehicle treatment. The results indicate that 7-nitroindazole is able to increase the protective activity of some conventional antiepileptics and this effect appears not to result only from the impaired synthesis of nitric oxide. In fact, mice receiving 7-nitroindazole (25 mg kg(-1), i.p.) and L-arginine (30 microg/mouse, intracerebroventricularly (i.c.v.) did not show significant changes of ED(50) values in comparison to those of related groups of animals treated with 7-nitroindazole and anticonvulsants. 7-Nitroindazole was able to increase the brain levels of dopamine and noradrenaline and its anticonvulsant effects and changes in catecholamine content were antagonized by pretreatment with alpha-methyl-paratyrosine, an agent inhibiting the synthesis of catecholamines. The fact that alpha-methyl-paratyrosine reverses concomitantly both the increase in brain levels of dopamine and noradrenaline and the anticonvulsant properties of 7-nitroindazole strongly suggests an important role of catecholamines in the antiseizure activity of 7-nitroindazole. Since 7-nitroindazole did not significantly influence the total and free plasma levels of the anticonvulsant drugs studied, we suggest that pharmacokinetic interactions, in terms of total or free plasma levels, are not probable. 7-Nitroindazole did not significantly affect the hypothermic effects of the anticonvulsant compounds studied. 7-Nitroindazole showed an additive effect when administered in combination with some classical anticonvulsants, most notably diazepam, phenobarbital and valproate and its activity could be, in part, due to an increase of monoamine levels.
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Affiliation(s)
- G De Sarro
- Chair of Pharmacology, Department of Experimental and Clinical Medicine, Faculty of Medicine and Surgery, School of Medicine at Catanzaro,University of Catanzaro "Magna Gracia" Policlinico Mater Domini,via T. Campanella, Catanzaro, Italy
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38
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Calixto E, López-Colomé AM, Casasola C, Montiel T, Bargas J, Brailowsky S. Neocortical hyperexcitability after GABA withdrawal in vitro. Epilepsy Res 2000; 39:13-26. [PMID: 10690749 DOI: 10.1016/s0920-1211(99)00100-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The sharp interruption of the intracortical instillation of exogenous gamma-aminobutyric acid (GABA), generates an epileptic focus in mammals. Seizures elicited by GABA withdrawal last several days or weeks. The present work reports that GABA withdrawal-induced hyperexcitability can be produced in vitro: a sudden withdrawal of GABA (5 mM; 120 min) or benzodiazepine (60 microM flunitrazepam) from the superfusion, induced a gradual increase in the amplitude of the evoked population spike (PS) recorded on neocortical slices. PS enhancement reached 150% above the control value 2.5 h after GABA withdrawal. GABA withdrawal-induced hyperexcitability was facilitated by progesterone. PS enhancement induced by GABA withdrawal was associated with an impairment of GABA transmission occurring before epileptiform discharges were fully established. Paired pulse inhibition and evoked [3H]-GABA release appear decreased; suggesting that cortical hyperexcitability as a result of GABA withdrawal involves pre-synaptic changes. Specific muscimol binding decreased during GABA superfusion but recovered after GABA withdrawal. However, the sensitivity of the post-synaptic response to 3alpha-OH-5alpha-pregnan-20-one or allopregnanolone (alloP) was enhanced after GABA withdrawal, suggesting a functional change in the GABA(A) receptors. The changes described may be the cellular correlates of the withdrawal syndromes appearing after interruption of the administration of GABA(A) receptor agonists.
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Affiliation(s)
- E Calixto
- Instituto de Fisiología Celular, UNAM, Mexico City DF, Mexico
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39
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Buckman J, Meshul C. Glial Differences Between Naive Withdrawal Seizure-Prone and -Resistant Mice. Alcohol Clin Exp Res 1999. [DOI: 10.1111/j.1530-0277.1999.tb04090.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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Abstract
The main goal of this article is to review certain aspects of the circuitry of the human cerebral cortex that may be particularly relevant for the development, maintenance or spread of seizures. There are a number of different structural abnormalities that are commonly found in the cortex of epileptic patients, but these abnormalities do not appear to be intrinsically epileptogenic, since some patients displaying them are epileptic (after variable delays) whereas others are not. Therefore, cortical circuits in an affected brain may undergo a series of changes that finally cause epilepsy. In this article, it is proposed that the chandelier cell, which is considered to be the most powerful cortical GABAergic inhibitory interneuron, is probably a key component of cortical circuits in the establishment of human intractable temporal lobe epilepsy. These cells (among other types) have been found to be lost or reduced at epileptic foci in both experimental animals and epileptic patients. A hypothesis is presented by which the normal variability in the number of interneurons might explain the predisposition of some individuals to develop epilepsy more than others as a result of a lesion or other precipitating factors that lead to loss of neurons. The sources of GABAergic input on dendrites and somata of cortical pyramidal cells originate from many and diverse types of interneurons but, at the level of the axon initial segment of these cells, all synapses come from a few chandelier cells (five or less). Loss of one class of interneurons ending on soma and dendrites might have relatively little impact on the inhibitory control of the pyramidal cell. However, if chandelier cells were affected, it would have serious consequences for the inhibitory control of the pyramidal cells. Evidence suggests that the loss of chandelier cells may be non-specific and that when this occurs epilepsy may develop. Therefore, these cells might represent a key component in the aetiology of human temporal lobe epilepsy.
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Abstract
Carbamazepine (CBZ) is widely used in the treatment of epilepsy, frequently in combination with other anticonvulsants. Its metabolite, carbamazepine-10,11-epoxide, is pharmacologically active and is increased with concurrent use of valproate and other anticonvulsants. This pharmacokinetic interaction may be particularly important because CBZ, its epoxide, phenytoin, and lamotrigine all act on fast voltage-dependent sodium channels. Over a 2-month period, routine serum requests for CBZ (n=47) (excluding known cases of overdose) were also analyzed for CBZ epoxide, phenytoin, and lamotrigine using a simultaneous high performance liquid chromatographic (HPLC) method. Valproate was measured using fluorescence polarization immunoassay (FPIA). With concurrent phenytoin and lamotrigine administration, there was a relative increase in CBZ epoxide and a significant decrease in the ratio of CBZ to epoxide (from more than 5 to 3). If valproate was also present, the concentration of parent and metabolite increased significantly, causing potential toxicity. Two patients in this latter group had significant clinical toxicity, with parent CBZ concentrations in the reference range; a third patient suffered from poor control of seizures. This study illustrates the importance of awareness of the contribution of active metabolites in therapeutic drug monitoring and raises questions about the role of the routine monitoring of such metabolites.
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Affiliation(s)
- J M Potter
- Division of Chemical Pathology, Queensland Health Pathology Services, Royal Brisbane Hospitals Campus, Herston, Australia
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42
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Lores Arnaiz S, Travacio M, Llesuy S, Rodríguez de Lores Arnaiz G. Regional vulnerability to oxidative stress in a model of experimental epilepsy. Neurochem Res 1998; 23:1477-83. [PMID: 9821150 DOI: 10.1007/bf03177490] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
We evaluated oxidative stress associated with a model of experimental epilepsy. Male Wistar rats were injected i.p. with 150 mg/kg convulsant 3-mercaptopropionic acid and decapitated in two stages: during seizures or in the post-seizure period. Spontaneous chemiluminescence, levels of thiobarbituric acid reactive substances, total antioxidant capacity and antioxidant enzyme activities were measured in cerebellum, hippocampus, cerebral cortex and striatum. In animals killed at seizure, increases of 42% and 90% were observed in spontaneous chemiluminescence of cerebellum and cerebral cortex homogenates, respectively, accompanied by a 25% increase in cerebral cortex levels of thiobarbituric acid reactive substances. In the post-seizure stage, emission completely returned to control levels in cerebral cortex and partly in cerebellum, thus showing oxidative stress reversibility in time. Hippocampus and striatum seemed less vulnerable areas to oxidative damage. A 30% decrease in glutathione peroxidase activity was only observed in cerebral cortex during seizures, while catalase and superoxide dismutase remained unchanged in all four areas during either stage. Likewise, total antioxidant capacity was unaffected in any of the studied areas. It is suggested that oxidative stress in this model of epilepsy arises from an increase in oxidant species rather than from depletion of antioxidant defences.
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Affiliation(s)
- S Lores Arnaiz
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
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43
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Wu SP, Tsai JJ, Gean PW. Frequency-dependent inhibition of neuronal activity by topiramate in rat hippocampal slices. Br J Pharmacol 1998; 125:826-32. [PMID: 9831921 PMCID: PMC1571030 DOI: 10.1038/sj.bjp.0702096] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Topiramate is a structurally novel anticonvulsant which was recently approved for adjunctive therapy in partial and secondarily generalized seizures. The present study was aimed at elucidating the mechanisms underlying the anticonvulsant efficacy of topiramate using intra- and extracellular recording techniques in the in vitro hippocampal slices. 2. When stimuli were delivered every 20 s, topiramate had no measurable effect on both field excitatory postsynaptic potentials (fEPSPs) and population spikes (PSs). However, increasing the stimulation frequency from 0.05-0.2 Hz, topiramate significantly decreased the slope of fEPSP and the amplitude of PS in a concentration-dependent manner. The amplitude of presynaptic fiber volley was also reduced. 3. Topiramate did not affect the magnitude of paired-pulse inhibition and monosynaptically evoked inhibitory postsynaptic potentials (IPSPs). 4. Sustained repetitive firing was elicited by injection of long duration (500 ms) depolarizing current pulses (500-800 pA). Superfusion with topiramate significantly reduced the number of action potentials evoked by a given current pulse. 5. After blockade of GABA receptors by bicuculline, burst firing which consisted of a train of several spikes riding on a large depolarizing wave termed paroxysmal depolarizing shift (PDS) was recorded. Application of topiramate reduced the duration of PDS and later spikes with less effect on the initial action potential. 6. These results suggest that frequency-dependent inhibition of neuronal activity due to blockade of Na+ channels may account largely for the anticonvulsant efficacy of topiramate.
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Affiliation(s)
- S P Wu
- Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan City, Taiwan
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44
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Sperk G, Schwarzer C, Tsunashima K, Kandlhofer S. Expression of GABA(A) receptor subunits in the hippocampus of the rat after kainic acid-induced seizures. Epilepsy Res 1998; 32:129-39. [PMID: 9761315 DOI: 10.1016/s0920-1211(98)00046-1] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The GABA(A) receptor is a ligand gated chloride channel consisting of five membrane spanning proteins for which 13 different genes have been identified in the mammalian brain. The present review summarizes recent work from our laboratory on the characterization of the immunocytochemical distribution of these GABA(A) receptor subunits in the rat brain and changes in immunoreactivity and mRNA expression after kainic acid-induced status epilepticus. A heterogeneous distribution of immunoreactive GABA(A) receptor subunits was observed. The most abundant ones were: alpha1, alpha2, alpha4, alpha5, beta2, beta3, gamma2, and delta. Alpha1, beta2, and gamma2 were about equally distributed in all subfields of the hippocampus; alpha4- and delta-subunits were preferentially found in the dentate molecular layer and in CA1; alpha2 was localized to the dentate molecular layer and CA3; alpha5 was found in the dendritic areas of CA1 to CA3; and beta1 was preferentially seen in CA2. Alpha1, beta2, gamma2 and delta were highly concentrated in interneurons. Kainic acid-induced seizures caused acute and chronic changes in the expression of mRNAs and immunoreactive proteins. Acute changes included decreases in alpha2, alpha5, beta1, beta3, gamma2 and delta mRNA levels (by about 25-50%), accompanied by increases (by about 50%) in alpha1, alpha4, and beta2 messages in granule cells (after 6-12 h). Chronic changes, characterized by losses in mRNA and immunoreactive proteins in CA1 and CA3, are undoubtedly due to seizure-related cell damage. However, compensatory expression of alpha2 and beta3 subunits, especially in CA3b/c, was observed. Furthermore, increases in mRNAs and immunoreactive proteins were seen for alpha1, alpha2 alpha4, beta1, beta2, beta3 and gamma2 in granule cells and in the molecular layer of the dentate gyrus at 7-30 days after kainic acid injection. The changes in the expression of GABA(A) receptor subunits, observed in practically all hippocampal subfields, may reflect altered GABA-ergic transmission during development of the epileptic syndrome. Increased expression of GABA(A) receptor subunits in the dendritic field of granule cells and CA3 suggest that GABA-ergic inhibition may be augmented at these levels. However, the lasting preservation of alpha1-, beta2-, and gamma2-subunits in interneurons could provide a basis for augmented inhibition of GABA-ergic interneurons, leading to net disinhibition.
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Affiliation(s)
- G Sperk
- Department of Pharmacology, University of Innsbruck, Austria.
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45
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Lima TT, Begnini J, de Bastiani J, Fialho DB, Jurach A, Ribeiro MC, Wajner M, de Mello CF. Pharmacological evidence for GABAergic and glutamatergic involvement in the convulsant and behavioral effects of glutaric acid. Brain Res 1998; 802:55-60. [PMID: 9748501 DOI: 10.1016/s0006-8993(98)00563-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effect of intrastriatal administration of glutaric acid (GTR), a metabolite that accumulates in glutaric acidemia type I (GA-I), on the behavior of adult male rats was investigated. After cannula placing, rats received unilateral intrastriatal injections of GTR buffered to pH 7.4 with NaOH or NaCl. GTR induced rotational behavior toward the contralateral side of injection and clonic convulsions in a dose-dependent manner. Rotational behavior was prevented by intrastriatal preadministration of DNQX and muscimol, but not by the preadministration of MK-801. Convulsions were prevented by intrastriatal preinjection of muscimol. This study provides evidence for a participation of glutamatergic non-NMDA and GABAergic mechanisms in the GTR-induced behavioral alterations. These findings may be of value in understanding the physiopathology of the neurological dysfunction in glutaric acidemia.
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Affiliation(s)
- T T Lima
- Departamento de Química, Universidade Federal de Santa Maria, Brazil
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46
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Hirao T, Morimoto K, Yamamoto Y, Watanabe T, Sato H, Sato K, Sato S, Yamada N, Tanaka K, Suwaki H. Time-dependent and regional expression of GABA transporter mRNAs following amygdala-kindled seizures in rats. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1998; 54:49-55. [PMID: 9526043 DOI: 10.1016/s0169-328x(97)00323-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To investigate the role played by GABA transporters in epileptic seizures, we examined time-dependent and regional changes in expression of GAT-1 and GAT-3 GABA transporter mRNA in amygdala-kindled rat brain using an in situ hybridization method. GAT-1 mRNA was significantly increased bilaterally in the hippocampal dentate gyrus (111-116%) at 1 h after kindled generalized seizures. GAT-1 mRNA was also significantly increased bilaterally in the hippocampal subfields (CA1-4 and dentate gyrus [110-117%]) at 4 h after kindled seizures. There were no significant changes in GAT-1 mRNA level in the amygdalar nuclei, pyriform cortex or cerebral cortex either ipsilaterally or contralaterally at any time after kindled seizures. In contrast, GAT-3 mRNA was significantly increased bilaterally in the amygdalar nuclei and in the contralateral pyriform cortex and cerebral cortex 1 h after seizures. Since all these changes returned to control levels by 8 or 24 h after kindled seizures, the increases in GABA transporter mRNA appeared to be transient responses to seizure activity. These findings indicate that GAT-1 subtype transporter is specifically involved in seizure activity in the hippocampus, while GAT-3 subtype transporter is mainly involved in seizure activity in the amygdalar nuclei and pyriform cortex following amygdala-kindled generalized seizures.
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Affiliation(s)
- T Hirao
- Department of Neuropsychiatry, Faculty of Medicine, Kagawa Medical University, Japan
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47
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Affiliation(s)
- J P Leach
- University Department of Medicine and Therapeutics, Western Infirmary, Glasgow, UK
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48
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Singh NA, Charlier C, Stauffer D, DuPont BR, Leach RJ, Melis R, Ronen GM, Bjerre I, Quattlebaum T, Murphy JV, McHarg ML, Gagnon D, Rosales TO, Peiffer A, Anderson VE, Leppert M. A novel potassium channel gene, KCNQ2, is mutated in an inherited epilepsy of newborns. Nat Genet 1998; 18:25-9. [PMID: 9425895 DOI: 10.1038/ng0198-25] [Citation(s) in RCA: 836] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Idiopathic generalized epilepsies account for about 40% of epilepsy up to age 40 and commonly have a genetic basis. One type is benign familial neonatal convulsions (BFNC), a dominantly inherited disorder of newborns. We have identified a sub-microscopic deletion of chromosome 20q13.3 that co-segregates with seizures in a BFNC family. Characterization of cDNAs spanning the deleted region identified one encoding a novel voltage-gated potassium channel, KCNQ2, which belongs to a new KQT-like class of potassium channels. Five other BFNC probands were shown to have KCNQ2 mutations, including two transmembrane missense mutations, two frameshifts and one splice-site mutation. This finding in BFNC provides additional evidence that defects in potassium channels are involved in the mammalian epilepsy phenotype.
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Affiliation(s)
- N A Singh
- Department of Human Genetics, University of Utah, Salt Lake City 84112, USA
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49
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Fukuda M, Morimoto T, Nagao H, Kida K. The effect of GABAergic system activity on hyperthermia-induced seizures in rats. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1997; 104:197-9. [PMID: 9466722 DOI: 10.1016/s0165-3806(97)00157-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Developing rats were given GABA antagonists and agonist before electrical seizure discharges were induced by heating the brain of a rat with infra-red rays. The thresholds for the GABA antagonist groups were significantly lower than that for the control, and the threshold for the GABA agonist group was significantly higher than that for the control. These results support the hypothesis that reduced GABAergic system activity underlies febrile seizures.
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Affiliation(s)
- M Fukuda
- Department of Pediatrics, Ehime University School of Medicine, Japan
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50
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Pereira P, Elisabetsky E, Souza DO. Effect of gamma-decanolactone on glutamate binding in the rat cerebral cortex. Neurochem Res 1997; 22:1507-10. [PMID: 9357017 DOI: 10.1023/a:1021962714034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Epilepsy is one of the most common neurological disorders. Even though antiepileptic drugs can afford a reasonably satisfactory treatment for 80% of diagnosed patients, chronic intractable epilepsy still affects a significant number of people and more effective and less harmful antiepileptic drugs are needed. Previous studies have shown that gamma-decanolactone has dose-dependent sedative effects, including hypnotic, anticonvulsant and hypothermic properties in mice. The present study reports an inhibitory effect of gamma-decanolactone on glutamate binding (96.8% with 5 mM) in rat cortex membranes. The non competitive nature of glutamate binding inhibition as a neurochemical correlate of the anticonvulsant activity of gamma-decanolactone may be a relevant mode of action for further drug development.
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Affiliation(s)
- P Pereira
- Departamento de Farmacologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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