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Onitsuka T, Tsuchimoto R, Oribe N, Spencer KM, Hirano Y. Neuronal imbalance of excitation and inhibition in schizophrenia: a scoping review of gamma-band ASSR findings. Psychiatry Clin Neurosci 2022; 76:610-619. [PMID: 36069299 DOI: 10.1111/pcn.13472] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 08/04/2022] [Accepted: 08/16/2022] [Indexed: 12/01/2022]
Abstract
Recent empirical findings suggest that altered neural synchronization, which is hypothesized to be associated with an imbalance of excitatory (E) and inhibitory (I) neuronal activities, may underlie a core pathophysiological mechanism in patients with schizophrenia. The auditory steady-state response (ASSR) examined by electroencephalography (EEG) and magnetoencephalography (MEG) has been proposed as a potential biomarker for evaluating altered neural synchronization in schizophrenia. For this review, we performed a comprehensive literature search for papers published between 1999 and 2021 examining ASSRs in patients with schizophrenia. Almost all EEG-ASSR studies reported gamma-band ASSR reductions, especially to 40-Hz stimuli both in power and/or phase synchronization in chronic and first-episode schizophrenia. In addition, similar to EEG-ASSR findings, MEG-ASSR deficits to 80-Hz stimuli (high gamma) have been reported in patients with schizophrenia. Moreover, the 40-Hz ASSR is likely to be a predictor of the onset of schizophrenia. Notably, increased spontaneous (or ongoing) broadband (30-100 Hz) gamma power has been reported during ASSR tasks, which resembles the increased spontaneous gamma activity reported in animal models of E/I imbalance. Further research on ASSRs and evoked and spontaneous gamma oscillations is expected to elucidate the pathophysiology of schizophrenia with translational implications.
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Affiliation(s)
- Toshiaki Onitsuka
- Department of Neuroimaging Psychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Rikako Tsuchimoto
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Naoya Oribe
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Division of Clinical Research, National Hospital Organization, Hizen Psychiatric Medical Center, Saga, Japan
| | - Kevin M Spencer
- Neural Dynamics Laboratory, Research Service, Veterans Affairs Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, 02130, USA.,Clinical Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, Boston VA Healthcare System, Brockton Division and Harvard Medical School, Brockton, Massachusetts, USA
| | - Yoji Hirano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Neural Dynamics Laboratory, Research Service, Veterans Affairs Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, Massachusetts, 02130, USA.,Clinical Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, Boston VA Healthcare System, Brockton Division and Harvard Medical School, Brockton, Massachusetts, USA
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2
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Osmanlıoğlu Ş, Yildiz A, Vardi N, Karaaslan M, Ozhan O, Parlakpinar H. Effects of antiepileptic drugs on ovaries of female Wistar rats. Biotech Histochem 2021; 97:261-268. [PMID: 34281441 DOI: 10.1080/10520295.2021.1946713] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Valproate (VPA) induced changes in ovarian morphology are observed in humans with epilepsy and in non-epileptic animals. The effects of lamotrigine (LTG) on female reproduction is not well known. We investigated whether LTG might be a safer drug for use with patients of reproductive age. Forty Wistar albino female rats were divided into five groups. The control group was injected with saline-vehicle solution. The low dose (LD)-VPA group was injected with 100 mg/kg VPA. The high dose (HD)-VPA group was injected with 500 mg/kg VPA. The LD-LTG group was injected with 10 mg/kg LTG. The HD-LTG group was injected with 50 mg/kg LTG. We evaluated histological and biochemical changes in the ovaries. The number of atretic and cystic follicles was increased in the HD-VPA and HD-LTG groups compared to the control group. A significant increase in malondialdehyde level was found in the VPA groups compared to the control and LTG groups. No significant differences in total glutathione levels or superoxide dismutase activity were found among study groups. Catalase activity was significantly higher in HD-VPA and HD-LTG groups compared to the control, LD-VPA and LD-LTG groups. Prevalence and intensity of caspase-3 immunoreactivity in the luteal cells were significantly greater in the HD-LTG group compared to the control group. VPA administration caused polycystic ovarian syndrome-like changes in the ovary. We found that LD-LTG, which reflects the dose for humans, might be a safer option for use during the reproductive age.
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Affiliation(s)
- Şeyma Osmanlıoğlu
- Department of Gynecology and Obstetrics, Faculty of Medicine, Ankara Medipol University, Ankara, Turkey
| | - Azibe Yildiz
- Department of Histology and Embryology, Faculty of Medicine, Inonu University, Malatya, Turkey
| | - Nigar Vardi
- Department of Chemistry, Faculty of Science, Inonu University, Malatya, Turkey.,Department of Property Protection and Security, askent Vocational High School, Selcuk University, Konya, Turkey
| | - Merve Karaaslan
- Department of Histology and Embryology, Faculty of Medicine, Inonu University, Malatya, Turkey
| | - Onural Ozhan
- Department of Medical Pharmacology, Faculty of Medicine, Inonu University, Malatya, Turkey
| | - Hakan Parlakpinar
- Department of Medical Pharmacology, Faculty of Medicine, Inonu University, Malatya, Turkey
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Brown M, Turgeon C, Rinaldo P, Roullet JB, Gibson KM. Temporal metabolomics in dried bloodspots suggests multipathway disruptions in aldh5a1 -/- mice, a model of succinic semialdehyde dehydrogenase deficiency. Mol Genet Metab 2019; 128:397-408. [PMID: 31699650 DOI: 10.1016/j.ymgme.2019.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 08/26/2019] [Accepted: 10/05/2019] [Indexed: 02/08/2023]
Abstract
Succinic semialdehyde dehydrogenase (SSADH) deficiency (SSADHD; OMIM 271980) is a rare disorder featuring accumulation of neuroactive 4-aminobutyric acid (GABA; γ-aminobutyric acid, derived from glutamic acid) and 4-hydroxybutyric acid (γ-hydroxybutyric acid; GHB, a short-chain fatty acid analogue of GABA). Elevated GABA is predicted to disrupt the GABA shunt linking GABA transamination to the Krebs cycle and maintaining the balance of excitatory:inhibitory neurotransmitters. Similarly, GHB (or a metabolite) is predicted to impact β-oxidation flux. We explored these possibilities employing temporal metabolomics of dried bloodspots (DBS), quantifying amino acids, acylcarnitines, and guanidino- metabolites, derived from aldh5a1+/+, aldh5a1+/- and aldh5a1-/- mice (aldehyde dehydrogenase 5a1 = SSADH) at day of life (DOL) 20 and 42 days. At DOL 20, aldh5a1-/- mice had elevated C6 dicarboxylic (adipic acid) and C14 carnitines and threonine, combined with a significantly elevated ratio of threonine/[aspartic acid + alanine], in comparison to aldh5a1+/+ mice. Conversely, at DOL 42 aldh5a1-/- mice manifested decreased short chain carnitines (C0-C6), valine and glutamine, in comparison to aldh5a1+/+ mice. Guanidino species, including creatinine, creatine and guanidinoacetic acid, evolved from normal levels (DOL 20) to significantly decreased values at DOL 42 in aldh5a1-/- as compared to aldh5a1+/+ mice. Our results provide a novel temporal snapshot of the evolving metabolic profile of aldh5a1-/- mice while highlighting new pathomechanisms in SSADHD.
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Affiliation(s)
- Madalyn Brown
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, United States of America
| | - Coleman Turgeon
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Piero Rinaldo
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States of America
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, United States of America
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, United States of America.
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Excitatory and inhibitory synaptic dysfunction in mania: an emerging hypothesis from animal model studies. Exp Mol Med 2018; 50:1-11. [PMID: 29628501 PMCID: PMC5938027 DOI: 10.1038/s12276-018-0028-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 11/29/2017] [Indexed: 12/26/2022] Open
Abstract
Bipolar disorder (BD) is a common psychiatric disorder characterized by recurrent mood swings between depression and mania, and is associated with high treatment costs. The existence of manic episodes is the defining feature of BD, during which period, patients experience extreme elevation in activity, energy, and mood, with changes in sleep patterns that together severely impair their ability to function in daily life. Despite some limitations in recapitulating the complex features of human disease, several rodent models of mania have been generated and characterized, which have provided important insights toward understanding its underlying pathogenic mechanisms. Among the mechanisms, neuronal excitatory and inhibitory (E/I) synaptic dysfunction in some brain regions, including the frontal cortex, hippocampus, and striatum, is an emerging hypothesis explaining mania. In this review, we highlight recent studies of rodent manic models having impairments in the E/I synaptic development and function. We also summarize the molecular and functional changes of E/I synapses by some mood stabilizers that may contribute to the therapeutic efficacy of drugs. Furthermore, we discuss potential future directions in the study of this emerging hypothesis to better connect the outcomes of basic research to the treatment of patients with this devastating mental illness. Studies in rodents offer insights into bipolar disorder that may help understanding and treatment of this common and debilitating condition. Kihoon Han and colleagues at Korea University in Seoul review research using mice and rats to model the episodes of mania in patients with bipolar disorder. The research supports an emerging hypothesis implicating specific problems with nervous transmission in the brain in the onset of mania. The hypothesis suggests that the transmission of signals between particular nerve cells whose normal function is either to excite or to inhibit other nerve cells may be involved. It also indicates regions of the brain most involved in manic episodes. Changes at the affected nerve junctions—called synapses—brought about by mood-stabilizing drugs are examined. The hypothesis suggests new approaches to treatment options for researchers to explore.
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Druschky K, Bleich S, Grohmann R, Engel RR, Kleimann A, Stübner S, Greil W, Toto S. Use and safety of antiepileptic drugs in psychiatric inpatients-data from the AMSP study. Eur Arch Psychiatry Clin Neurosci 2018; 268:191-208. [PMID: 28766129 DOI: 10.1007/s00406-017-0827-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/24/2017] [Indexed: 12/19/2022]
Abstract
The psychiatric utilization patterns and risks of antiepileptic drugs (AEDs) were assessed by using data from the drug safety programme Arzneimittelsicherheit in der Psychiatrie over the time period 1993-2013. In a total of 432,215 patients, the main indications for AED use were acute mania, schizoaffective disorder, and schizophrenic and organic psychoses. Valproic acid (VPA) was the most common substance across all of those groups, reaching administration rates of up to 50% since 2005, at which time carbamazepine (CBZ) administration consistently dropped below a rate of 10%. Lamotrigine (LTG) and pregabalin (PGB) increased in relevance after 2005 and 2010, respectively (with administration rates of up to 9%), whereas oxcarbazepine (OXC) was least prevalent (<3%). The mean rates of severe adverse drug reactions (ADRs) ranged from 6 cases per 1000 patients treated (VPA) to 19/1000 (OXC) and were significantly lower with treatment with VPA compared to OXC and CBZ. Hyponatremia was the leading ADR during treatment with OXC; severe allergic skin reactions were most often observed during treatment with CBZ and LTG, and severe oedema was most common during treatment with PGB. Severe hyponatremia induced by OXC was observed significantly more often in female patients than in male patients.
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Affiliation(s)
- Katrin Druschky
- Department of Neurology, University of Erlangen-Nuernberg, Schwabachanlage 6, 91054, Erlangen, Germany.
| | - Stefan Bleich
- Department of Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical School, Hannover, Germany
| | - Renate Grohmann
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University of Munich, Nussbaumstraße 7, 80336, Munich, Germany
| | - Rolf R Engel
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University of Munich, Nussbaumstraße 7, 80336, Munich, Germany
| | - Alexandra Kleimann
- Department of Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical School, Hannover, Germany
| | - Susanne Stübner
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University of Munich, Nussbaumstraße 7, 80336, Munich, Germany
| | - Waldemar Greil
- Department of Psychiatry and Psychotherapy, Ludwig Maximilian University of Munich, Nussbaumstraße 7, 80336, Munich, Germany.,Psychiatric Hospital Kilchberg, Kilchberg-Zurich, Switzerland
| | - Sermin Toto
- Department of Psychiatry, Social Psychiatry and Psychotherapy, Hannover Medical School, Hannover, Germany
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6
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Alda M, McKinnon M, Blagdon R, Garnham J, MacLellan S, O'Donovan C, Hajek T, Nair C, Dursun S, MacQueen G. Methylene blue treatment for residual symptoms of bipolar disorder: randomised crossover study. Br J Psychiatry 2017; 210:54-60. [PMID: 27284082 DOI: 10.1192/bjp.bp.115.173930] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 12/14/2015] [Accepted: 02/01/2016] [Indexed: 01/15/2023]
Abstract
BACKGROUND Residual symptoms and cognitive impairment are among important sources of disability in patients with bipolar disorder. Methylene blue could improve such symptoms because of its potential neuroprotective effects. AIMS We conducted a double-blind crossover study of a low dose (15 mg, 'placebo') and an active dose (195 mg) of methylene blue in patients with bipolar disorder treated with lamotrigine. METHOD Thirty-seven participants were enrolled in a 6-month trial (trial registration: NCT00214877). The outcome measures included severity of depression, mania and anxiety, and cognitive functioning. RESULTS The active dose of methylene blue significantly improved symptoms of depression both on the Montgomery-Åsberg Depression Rating Scale and Hamilton Rating Scale for Depression (P = 0.02 and 0.05 in last-observation-carried-forward analysis). It also reduced the symptoms of anxiety measured by the Hamilton Rating Scale for Anxiety (P = 0.02). The symptoms of mania remained low and stable throughout the study. The effects of methylene blue on cognitive symptoms were not significant. The medication was well tolerated with transient and mild side-effects. CONCLUSIONS Methylene blue used as an adjunctive medication improved residual symptoms of depression and anxiety in patients with bipolar disorder.
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Affiliation(s)
- Martin Alda
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Margaret McKinnon
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Ryan Blagdon
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Julie Garnham
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Susan MacLellan
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Claire O'Donovan
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Tomas Hajek
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Cynthia Nair
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Serdar Dursun
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
| | - Glenda MacQueen
- Martin Alda, MD, FRCPC, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Margaret McKinnon, PhD, Department of Psychiatry and Neuroscience, McMaster University, Hamilton, Mood Disorders Program, St Joseph's Healthcare, Hamilton and Homewood Research Institute, Guelph, Ontario; Ryan Blagdon, MSc, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia; Julie Garnham, RN, BN, Susan MacLellan, RN, Capital District Health Authority, Halifax, Nova Scotia; Claire O'Donovan, MB, FRCPC, Tomas Hajek, MD, PhD, Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia; Cynthia Nair, MD, FRCPC, Associate Medical Clinic, Prince Albert, Saskatchewan; Serdar Dursun, MD, PhD, FRCPC, Department of Psychiatry, University of Alberta, Edmonton, Alberta; Glenda MacQueen, MD, PhD, FRCPC, Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada
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7
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Oja SS, Saransaari P. Taurine and epilepsy. Epilepsy Res 2013; 104:187-94. [DOI: 10.1016/j.eplepsyres.2013.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/19/2012] [Accepted: 01/18/2013] [Indexed: 10/27/2022]
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8
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Ramadan E, Basselin M, Rao JS, Chang L, Chen M, Ma K, Rapoport SI. Lamotrigine blocks NMDA receptor-initiated arachidonic acid signalling in rat brain: implications for its efficacy in bipolar disorder. Int J Neuropsychopharmacol 2012; 15:931-43. [PMID: 21733229 PMCID: PMC3204186 DOI: 10.1017/s1461145711001003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
An up-regulated brain arachidonic acid (AA) cascade and a hyperglutamatergic state characterize bipolar disorder (BD). Lamotrigine (LTG), a mood stabilizer approved for treating BD, is reported to interfere with glutamatergic neurotransmission involving N-methyl-d-aspartate receptors (NMDARs). NMDARs allow extracellular calcium into the cell, thereby stimulating calcium-dependent cytosolic phospholipase A2 (cPLA2) to release AA from membrane phospholipid. We hypothesized that LTG, like other approved mood stabilizers, would reduce NMDAR-mediated AA signalling in rat brain. An acute subconvulsant dose of NMDA (25 mg/kg) or saline was administered intraperitoneally to unanaesthetized rats that had been treated p.o. daily for 42 d with vehicle or a therapeutically relevant dose of LTG (10 mg/kg.d). Regional brain AA incorporation coefficients k* and rates J in, and AA signals, were measured using quantitative autoradiography after intravenous [1-14C]AA infusion, as were other AA cascade markers. In chronic vehicle-treated rats, acute NMDA compared to saline increased k* and J in in widespread regions of the brain, as well as prostaglandin (PG)E2 and thromboxane B2 concentrations. Chronic LTG treatment compared to vehicle reduced brain cyclooxygenase (COX) activity, PGE2 concentration, and DNA-binding activity of the COX-2 transcription factor, NF-κB. Pretreatment with chronic LTG blocked the acute NMDA effects on AA cascade markers. In summary, chronic LTG like other mood stabilizers blocks NMDA-mediated signalling involving the AA metabolic cascade. Since markers of the AA cascade and of NMDAR signalling are up-regulated in the post-mortem BD brain, mood stabilizers generally may be effective in BD by dampening NMDAR signalling and the AA cascade.
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Affiliation(s)
- Epolia Ramadan
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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9
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Oda Y, Onitsuka T, Tsuchimoto R, Hirano S, Oribe N, Ueno T, Hirano Y, Nakamura I, Miura T, Kanba S. Gamma band neural synchronization deficits for auditory steady state responses in bipolar disorder patients. PLoS One 2012; 7:e39955. [PMID: 22792199 PMCID: PMC3390322 DOI: 10.1371/journal.pone.0039955] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 05/29/2012] [Indexed: 11/19/2022] Open
Abstract
Periodic auditory click stimulation has been reported to elicit an auditory steady state response (ASSR). The ASSR has been suggested to reflect the efficiency of γ-amino butyric acid (GABA) inhibitory interneuronal activity. Although a potential role for GABAergic dysfunction has been previously proposed, the role of neural synchronization in the ASSR in people with bipolar disorder (BD) has received little attention. In the current study, we investigated ASSRs to 20 Hz, 30 Hz, 40 Hz and 80 Hz click trains in BD patients. A total of 14 (4 males) BD patients and 25 (10 males) healthy controls participated in this study. ASSRs were obtained using whole-head 306-channel magnetoencephalography to calculate, ASSR power values and phase locking factors (PLF). BD patients exhibited significantly reduced mean ASSR power and PLF values bilaterally at frequencies of 30, 40, and 80 Hz (p<0.05 for these frequencies). At 20 Hz, bipolar patients showed no significant reduction in mean ASSR power and PLF values. There was a significant negative correlation between 80 Hz-ASSR-power values obtained from the right hemisphere and scores on the Hamilton Depression Rating Scale (rho = −0.86, p = 0.0003). The current study showed reduced low and high gamma band ASSR power and PLF bilaterally with no significant beta band ASSR reduction in BD patients. BD patients are characterized by deficits in gamma band oscillations, which may be associated with GABA inhibitory interneuronal activity dysfunction.
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Affiliation(s)
- Yuko Oda
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshiaki Onitsuka
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Rikako Tsuchimoto
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shogo Hirano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Naoya Oribe
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Clinical Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, Boston VA Healthcare System, Brockton Division and Harvard Medical School, Brockton, Massachusetts, United States of America
| | - Takefumi Ueno
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoji Hirano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Clinical Neuroscience Division, Laboratory of Neuroscience, Department of Psychiatry, Boston VA Healthcare System, Brockton Division and Harvard Medical School, Brockton, Massachusetts, United States of America
| | - Itta Nakamura
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomofumi Miura
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shigenobu Kanba
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- * E-mail:
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Ramadan E, Basselin M, Taha AY, Cheon Y, Chang L, Chen M, Rapoport SI. Chronic valproate treatment blocks D2-like receptor-mediated brain signaling via arachidonic acid in rats. Neuropharmacology 2011; 61:1256-64. [PMID: 21839100 PMCID: PMC3190603 DOI: 10.1016/j.neuropharm.2011.07.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Revised: 07/12/2011] [Accepted: 07/17/2011] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND OBJECTIVE Hyperdopaminergic signaling and an upregulated brain arachidonic acid (AA) cascade may contribute to bipolar disorder (BD). Lithium and carbamazepine, FDA-approved for the treatment of BD, attenuate brain dopaminergic D(2)-like (D(2), D(3), and D(4)) receptor signaling involving AA when given chronically to awake rats. We hypothesized that valproate (VPA), with mood-stabilizing properties, would also reduce D(2)-like-mediated signaling via AA. METHODS An acute dose of quinpirole (1 mg/kg) or saline was administered to unanesthetized rats that had been treated for 30 days with a therapeutically relevant dose of VPA (200 mg/kg/day) or vehicle. Regional brain AA incorporation coefficients, k*, and incorporation rates, J(in), markers of AA signaling and metabolism, were measured by quantitative autoradiography after intravenous [1-(14)C]AA infusion. Whole brain concentrations of prostaglandin (PG)E(2) and thromboxane (TX)B(2) also were measured. RESULTS Quinpirole compared to saline significantly increased k* in 40 of 83 brain regions, and increased brain concentrations of PGE(2) in chronic vehicle-treated rats. VPA treatment by itself reduced concentrations of plasma unesterified AA and whole brain PGE(2) and TXB(2), and blocked the quinpirole-induced increments in k* and PGE(2). CONCLUSION These results further provide evidence that mood stabilizers downregulate brain dopaminergic D(2)-like receptor signaling involving AA.
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Affiliation(s)
- Epolia Ramadan
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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11
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Abstract
Mitochondria provide most of the energy production in cells. They are involved in the regulation of free radicals, calcium buffering, and redox signaling and take part in the intrinsic pathway of apoptosis. Mutations or polymorphisms of mitochondrial DNA, mitochondria-mediated oxidative stress, decrease of adenosine triphosphate production, changes of intracellular calcium and oxidative stress are concerned in various diseases. There is increasing evidence that impaired functions of mitochondria are associated with mood disorders. It is suggested that disturbed energetic metabolism and/or reactive oxygen species production take part in the pathophysiology of mood disorders and could participate in the therapeutic effects or side-effects of antidepressants and mood stabilizers.
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Affiliation(s)
- Jana Hroudová
- Department of Psychiatry, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic.
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12
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Hassel B, Taubøll E, Shaw R, Gjerstad L, Dingledine R. Region-specific changes in gene expression in rat brain after chronic treatment with levetiracetam or phenytoin. Epilepsia 2010; 51:1714-20. [PMID: 20345932 DOI: 10.1111/j.1528-1167.2010.02545.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE It is commonly assumed that antiepileptic drugs (AEDs) act similarly in the various parts of the brain as long as their molecular targets are present. A few experimental studies on metabolic effects of vigabatrin, levetiracetam, valproate, and lamotrigine have shown that these drugs may act differently in different brain regions. We examined effects of chronic treatment with levetiracetam or phenytoin on mRNA levels to detect regional drug effects in a broad, nonbiased manner. METHODS mRNA levels were monitored in three brain regions with oligonucleotide-based microarrays. RESULTS Levetiracetam (150 mg/kg for 90 days) changed the expression of 65 genes in pons/medulla oblongata, two in hippocampus, and one in frontal cortex. Phenytoin (75 mg/kg), in contrast, changed the expression of only three genes in pons/medulla oblongata, but 64 genes in hippocampus, and 327 genes in frontal cortex. Very little overlap between regions or drug treatments was observed with respect to effects on gene expression. DISCUSSION We conclude that chronic treatment with levetiracetam or phenytoin causes region-specific and highly differential effects on gene expression in the brain. Regional effects on gene expression could reflect regional differences in molecular targets of AEDs, and they could influence the clinical profiles of AEDs.
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Affiliation(s)
- Bjørnar Hassel
- Department of Neurology, Division of Clinical Neuroscience, Rikshospitalet, Oslo, Norway
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13
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Lelevich VV, Vinitskaya AG, Lelevich SV. Modern conception on metabolism of γ-aminobutyric acid in the brain. NEUROCHEM J+ 2009. [DOI: 10.1134/s1819712409040023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Rapoport SI, Basselin M, Kim HW, Rao JS. Bipolar disorder and mechanisms of action of mood stabilizers. ACTA ACUST UNITED AC 2009; 61:185-209. [PMID: 19555719 DOI: 10.1016/j.brainresrev.2009.06.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Revised: 06/03/2009] [Accepted: 06/15/2009] [Indexed: 11/30/2022]
Abstract
Bipolar disorder (BD) is a major medical and social burden, whose cause, pathophysiology and treatment are not agreed on. It is characterized by recurrent periods of mania and depression (Bipolar I) or of hypomania and depression (Bipolar II). Its inheritance is polygenic, with evidence of a neurotransmission imbalance and disease progression. Patients often take multiple agents concurrently, with incomplete therapeutic success, particularly with regard to depression. Suicide is common. Of the hypotheses regarding the action of mood stabilizers in BD, the "arachidonic acid (AA) cascade" hypothesis is presented in detail in this review. It is based on evidence that chronic administration of lithium, carbamazepine, sodium valproate, or lamotrigine to rats downregulated AA turnover in brain phospholipids, formation of prostaglandin E(2), and/or expression of AA cascade enzymes, including cytosolic phospholipase A(2), cyclooxygenase-2 and/or acyl-CoA synthetase. The changes were selective for AA, since brain docosahexaenoic or palmitic acid metabolism, when measured, was unaffected, and topiramate, ineffective in BD, did not modify the rat brain AA cascade. Downregulation of the cascade by the mood stabilizers corresponded to inhibition of AA neurotransmission via dopaminergic D(2)-like and glutamatergic NMDA receptors. Unlike the mood stabilizers, antidepressants that increase switching of bipolar depression to mania upregulated the rat brain AA cascade. These observations suggest that the brain AA cascade is a common target of mood stabilizers, and that bipolar symptoms, particularly mania, are associated with an upregulated cascade and excess AA signaling via D(2)-like and NMDA receptors. This review presents ways to test these suggestions.
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Affiliation(s)
- Stanley I Rapoport
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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15
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Papazisis G, Kallaras K, Kaiki-Astara A, Pourzitaki C, Tzachanis D, Dagklis T, Kouvelas D. Neuroprotection by lamotrigine in a rat model of neonatal hypoxic-ischaemic encephalopathy. Int J Neuropsychopharmacol 2008; 11:321-9. [PMID: 17897482 DOI: 10.1017/s1461145707008012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Hypoxic-ischaemic (HI) encephalopathy is a severe complication of perinatal asphyxia and remains a frequent cause of a variety of brain disorders with long-term effects on the patients' life. The associated brain damage is strongly related to the toxic action of excitatory amino acids, especially glutamate and aspartate. Lamotrigine is an anti-epileptic drug that blocks the voltage-gated sodium channels of the presynaptic neuron and inhibits the release of glutamate. In the present study a well-established model of perinatal asphyxia in 7-d-old rats was used to investigate the effect of lamotrigine on HI-induced damage to different hippocampal brain structures, since disruption of this brain area is thought to play a key role in schizophrenia and epilepsy. Therefore, a combination of ischaemia, induced by unilateral occlusion of the left common carotid artery, followed by exposure to a 1-h period of hypoxia, was carried out in neonatal 7-d-old rats. Immediately after the insult, lamotrigine was given i.p. The histological outcome in the hippocampus was conducted and the tissue levels of glutamate, aspartate, GABA, and glutamine in the same area were determined. A remarkable reduction of HI-evoked damaged neurons in most of the investigated hippocampal regions was noted after lamotrigine administration. Furthermore, lamotrigine decreased the asphyxia-induced hippocampal tissue levels of glutamate and aspartate. Immediately after perinatal asphyxia GABA levels were enhanced, while levels of glutamine were decreased. Lamotrigine administration did not affect either GABA or glutamine levels. These results suggest a neuroprotective effect of lamotrigine in this particular animal model of neonatal HI encephalopathy.
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Affiliation(s)
- Georgios Papazisis
- Department of Pharmacology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
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16
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Chronic Administration of Lamotrigine Downregulates COX-2 mRNA and Protein in Rat Frontal Cortex. Neurochem Res 2007; 33:861-6. [DOI: 10.1007/s11064-007-9526-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 10/05/2007] [Indexed: 01/09/2023]
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17
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Lee HJ, Rao JS, Chang L, Rapoport SI, Bazinet RP. Chronic lamotrigine does not alter the turnover of arachidonic acid within brain phospholipids of the unanesthetized rat: implications for the treatment of bipolar disorder. Psychopharmacology (Berl) 2007; 193:467-74. [PMID: 17487474 DOI: 10.1007/s00213-007-0803-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 04/11/2007] [Indexed: 12/27/2022]
Abstract
RATIONALE Drugs that are effective in treating the manic phase of bipolar disorder (lithium, carbamazepine, and valproate) upon chronic administration to rats decrease the turnover of arachidonic acid in their brain phospholipids. Lamotrigine may not be effective in the manic phase, but is effective in delaying the depressive phase and for treating rapid cycling bipolar disorder. Thus, lamotrigine provides a pharmacological tool to differentiate if downregulation of arachidonic acid turnover is specific to drugs effective in the manic phase of bipolar disorder. MATERIALS AND METHODS To test this hypothesis, rats were administered lamotrigine (10 mg kg(-1) day(-1)) or vehicle intragastrically once daily for 42 days. In the unanesthetized rat, [1-(14)C]arachidonic acid was infused intravenously and arterial blood plasma was sampled until the animal was killed at 5 min, and its microwaved brain was subjected to chemical and radiotracer analysis. RESULTS Using equations from our fatty acid model, we found that chronic lamotrigine compared with vehicle did not alter the net incorporation rate of plasma arachidonic acid into brain phospholipids, nor did it alter the turnover of arachidonic acid within brain phospholipids. CONCLUSION Chronic lamotrigine, which is effective in the depressive phase or rapid cycling bipolar disorder does not alter brain arachidonic acid turnover in the unanesthetized rat. These results are consistent with the hypothesis that drugs effective in treating the manic phase of bipolar disorder decrease brain arachidonic acid turnover.
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Affiliation(s)
- Ho-Joo Lee
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA.
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Bough KJ, Wetherington J, Hassel B, Pare JF, Gawryluk JW, Greene JG, Shaw R, Smith Y, Geiger JD, Dingledine RJ. Mitochondrial biogenesis in the anticonvulsant mechanism of the ketogenic diet. Ann Neurol 2006; 60:223-35. [PMID: 16807920 DOI: 10.1002/ana.20899] [Citation(s) in RCA: 391] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The full anticonvulsant effect of the ketogenic diet (KD) can require weeks to develop in rats, suggesting that altered gene expression is involved. The KD typically is used in pediatric epilepsies, but is effective also in adolescents and adults. Our goal was to use microarray and complementary technologies in adolescent rats to understand its anticonvulsant effect. METHODS Microarrays were used to define patterns of gene expression in the hippocampus of rats fed a KD or control diet for 3 weeks. Hippocampi from control- and KD-fed rats were also compared for the number of mitochondrial profiles in electron micrographs, the levels of selected energy metabolites and enzyme activities, and the effect of low glucose on synaptic transmission. RESULTS Most striking was a coordinated upregulation of all (n = 34) differentially regulated transcripts encoding energy metabolism enzymes and 39 of 42 transcripts encoding mitochondrial proteins, which was accompanied by an increased number of mitochondrial profiles, a higher phosphocreatine/creatine ratio, elevated glutamate levels, and decreased glycogen levels. Consistent with increased energy reserves, synaptic transmission in hippocampal slices from KD-fed animals was resistant to low glucose. INTERPRETATION These data show that a calorie-restricted KD enhances brain metabolism. We propose an anticonvulsant mechanism of the KD involving mitochondrial biogenesis leading to enhanced alternative energy stores.
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Joo EY, Hong SB, Tae WS, Han SJ, Seo DW, Lee KH, Lee MH. Effect of lamotrigine on cerebral blood flow in patients with idiopathic generalised epilepsy. Eur J Nucl Med Mol Imaging 2006; 33:724-9. [PMID: 16528524 DOI: 10.1007/s00259-005-0029-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2005] [Accepted: 10/25/2005] [Indexed: 10/24/2022]
Abstract
PURPOSE The purpose of this study was to investigate the effects of the new anti-epileptic drug, lamotrigine, on cerebral blood flow by performing (99m)Tc-ethylcysteinate dimer (ECD) single-photon emission computed tomography (SPECT) before and after medication in patients with drug-naive idiopathic generalised epilepsy. METHODS Interictal (99m)Tc-ECD brain SPECT was performed before drug treatment started and then repeated after lamotrigine medication for 4-5 months in 30 patients with generalised epilepsy (M/F=14/16, 19.3+/-3.4 years). Seizure types were generalised tonic-clonic seizure in 23 patients and myoclonic seizures in seven. The mean lamotrigine dose used was 214.1+/-29.1 mg/day. For SPM analysis, all SPECT images were spatially normalised to the standard SPECT template and then smoothed using a 12-mm full-width at half-maximum Gaussian kernel. The paired t test was used to compare pre- and post-lamotrigine SPECT images. RESULTS SPM analysis of pre- and post-lamotrigine brain SPECT images showed decreased perfusion in bilateral dorsomedial nuclei of thalami, bilateral uncus, right amygdala, left subcallosal gyrus, right superior and inferior frontal gyri, right precentral gyrus, bilateral superior and inferior temporal gyri and brainstem (pons, medulla) after lamotrigine medication at a false discovery rate-corrected p<0.05. No brain region showed increased perfusion after lamotrigine administration. CONCLUSION Our study demonstrates for the first time the effect of lamotrigine on interictal cerebral perfusion in drug-naive idiopathic generalised epilepsy patients. In summary, lamotrigine medication was found to reduce perfusion in cortico-thalamo-limbic areas, the orbitofrontal cortex, and brainstem.
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Affiliation(s)
- Eun Yeon Joo
- Department of Neurology, College of Medicine, Ewha Womans University, Seoul, Korea
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20
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Large CH, Webster EL, Goff DC. The potential role of lamotrigine in schizophrenia. Psychopharmacology (Berl) 2005; 181:415-36. [PMID: 16001126 DOI: 10.1007/s00213-005-0020-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Accepted: 03/29/2005] [Indexed: 12/16/2022]
Abstract
RATIONALE Atypical antipsychotic drugs are the drugs of choice for the treatment of schizophrenia. However, despite advances, no treatments have been established for patients who fail to improve with the most effective of these, clozapine. The inhibition of dopamine transmission through blockade of dopamine D2 receptors is considered to be essential for antipsychotic efficacy, but it is postulated that modulation of glutamate transmission may be equally important. In support of this, symptoms similar to schizophrenia can be induced in healthy volunteers using N-methyl-D-aspartate (NMDA) antagonist drugs that are also known to enhance glutamate transmission. Furthermore, lamotrigine, which can modulate glutamate release, may add to or synergise with atypical antipsychotic drugs, some of which may themselves modulate glutamate transmission. OBJECTIVES We examine the evidence for the efficacy of lamotrigine. We consider how this fits with a glutamate neuron dysregulation hypothesis of the disorder. We discuss mechanisms by which lamotrigine might influence neuronal activity and glutamate transmission, and possible ways in which the drug might interact with antipsychotic medications. RESULTS Data from four clinical studies support the efficacy of adjunctive lamotrigine in the treatment of schizophrenia. In addition, and consistent with a glutamate neuron dysregulation hypothesis of schizophrenia, lamotrigine can prevent the psychotic symptoms or behavioural disruption induced by NMDA receptor antagonists in healthy volunteers or rodents. CONCLUSIONS The efficacy of lamotrigine is most likely explained within the framework of a glutamate neuron dysregulation hypothesis, and may arise primarily through the drugs ability to influence glutamate transmission and neural activity in the cortex. The drug is likely to act through inhibition of voltage-gated sodium channels, though other molecular interactions cannot be ruled out. Lamotrigine may add to or synergise with some atypical antipsychotic drugs acting on glutamate transmission; alternatively, they may act independently on glutamate and dopamine systems to bring about a combined therapeutic effect. We propose new strategies for the treatment of schizophrenia using a combination of anti-dopaminergic and anti-glutamatergic drugs.
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Affiliation(s)
- Charles H Large
- Department of Neuropharmacology, Psychiatry CEDD, GlaxoSmithKline SpA, Via Fleming 4, 37135, Verona, Italy.
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Idris NF, Repeto P, Neill JC, Large CH. Investigation of the effects of lamotrigine and clozapine in improving reversal-learning impairments induced by acute phencyclidine and D-amphetamine in the rat. Psychopharmacology (Berl) 2005; 179:336-48. [PMID: 15645224 DOI: 10.1007/s00213-004-2058-5] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2003] [Accepted: 09/22/2004] [Indexed: 11/30/2022]
Abstract
RATIONALE Phencyclidine (PCP), a glutamate/N-methyl-D-aspartate (NMDA) receptor antagonist, has been shown to induce a range of symptoms similar to those of patients with schizophrenia, while D-amphetamine induces predominantly positive symptoms. Previous studies in our laboratory have shown that PCP can selectively impair the performance of an operant reversal-learning task in the rat. Furthermore, we found that the novel antipsychotic ziprasidone, but not the classical antipsychotic haloperidol, could prevent the PCP-induced deficit. OBJECTIVES The aim of the present study was to validate the model further using the atypical antipsychotic clozapine and then to investigate the effects of lamotrigine, a broad-spectrum anticonvulsant that is known to reduce glutamate release in vitro and is able to prevent ketamine-induced psychotic symptoms in healthy human volunteers. A further aim was to compare effects of PCP and D-amphetamine in the test and investigate the effects of the typical antipsychotic haloperidol against the latter. METHODS Female hooded-Lister rats were food deprived and trained to respond for food in a reversal-learning paradigm. RESULTS PCP at 1.5 mg/kg and 2.0 mg/kg and D-amphetamine at 0.5 mg/kg significantly and selectively impaired performance in the reversal phase of the task. The cognitive deficit induced by 1.5 mg/kg PCP was attenuated by prior administration of lamotrigine (20 mg/kg and 30 mg/kg) or clozapine (5 mg/kg), but not haloperidol (0.05 mg/kg). In direct contrast, haloperidol (0.05 mg/kg), but not lamotrigine (25 mg/kg) or clozapine (5 mg/kg), prevented a similar cognitive impairment produced by D-amphetamine (0.5 mg/kg). CONCLUSIONS Our findings provide further data to support the use of PCP-induced disruption of reversal learning in rodents to investigate novel antipsychotic drugs. The results also provide evidence for different mechanisms of PCP and D-amphetamine-induced disruption of performance in the test, and their different sensitivities to typical and atypical antipsychotic drugs.
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Affiliation(s)
- N F Idris
- The School of Pharmacy, The University of Bradford, Bradford, West Yorkshire, BD7 1DP, UK
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Arban R, Maraia G, Brackenborough K, Winyard L, Wilson A, Gerrard P, Large C. Evaluation of the effects of lamotrigine, valproate and carbamazepine in a rodent model of mania. Behav Brain Res 2005; 158:123-32. [PMID: 15680200 DOI: 10.1016/j.bbr.2004.08.015] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2004] [Revised: 08/23/2004] [Accepted: 08/23/2004] [Indexed: 11/26/2022]
Abstract
Bipolar disorder is a psychiatric condition characterised by episodes of mania, depression, and underlying mood instability. Anticonvulsant drugs have an established place in the treatment of the disorder, but identifying novel drugs in this class is complicated by the absence of validated animal models. We have evaluated the efficacy of three anticonvulsant mood stabilising drugs (lamotrigine, valproate, and carbamazepine) in a model of mania, in which hyperactivity is induced by the combination of D-amphetamine and chlordiazepoxide. All three drugs were effective at preventing the hyperactivity. Lower doses of valproate and carbamazepine were required to prevent hyperactivity compared to doses required to block tonic-clonic seizures induced by pentylenetetrazole. Lamotrigine was equipotent in the two models. However, the complex pharmacology of the D-amphetamine/chlordiazepoxide model means that there may be several mechanisms by which hyperactivity can be reduced, and these may have more or less relevance to the treatment of bipolar disorder. To address this issue, we also evaluated effects of the three anticonvulsants on baseline locomotion, on activity in the presence of chlordiazepoxide alone, or on activity induced by D-amphetamine alone. Based on the results, we propose that hyperactivity induced by D-amphetamine/chlordiazepoxide may arise through dopaminergic drive coupled with disinhibition caused by low doses of the benzodiazepine. The efficacy of lamotrigine may then arise through a reduction in neuronal excitability or increased glutamate transmission, these latter a consequence of the disinhibition. Carbamazepine may also reduce excitability and glutamate release, but its broader pharmacology, manifested by sedation at higher doses complicates interpretation of its efficacy and reflects its poorer tolerability in the clinic. Valproate may be effective, at least in part, through an enhancement of GABAergic transmission. The predictive validity of the D-amphetamine/chlordiazepoxide model for efficacy in bipolar disorder remains to be established, and research with a wider range of clinically tested drugs is warranted to help validate the model further. In the meantime, the model may be useful for distinguishing novel anticonvulsant drugs with different mechanisms of action.
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Affiliation(s)
- Roberto Arban
- Department of Biology, Psychiatry CEDD, GlaxoSmithKline S.p.A., Via Fleming 4, 37135 Verona, Italy
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Ahmad S, Fowler LJ, Whitton PS. Effects of acute and chronic lamotrigine treatment on basal and stimulated extracellular amino acids in the hippocampus of freely moving rats. Brain Res 2004; 1029:41-7. [PMID: 15533314 DOI: 10.1016/j.brainres.2004.09.016] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2004] [Indexed: 10/26/2022]
Abstract
The antiepileptic drug lamotrigine (LTG) is a relatively novel anticonvulsant frequently used in polytherapy and increasingly in monotherapy. LTG is believed to act by reducing excitatory glutamate (GLU) release due to an inhibition of Na(+) channels. In the present study, we have investigated the effects of acute and chronic (up to 21 days) treatment with LTG on basal and either veratridine- or KCl-stimulated release of aspartate (ASP), GLU, taurine (TAU) and GABA in the hippocampus of freely moving rats using microdialysis. Additionally, we have measured LTG concentrations in the plasma, whole brain and extracellular fluid of rats at the same time points. LTG significantly reduced basal ASP and GLU but only at the highest dose used (20 mg/kg) and was entirely without effect on basal TAU or GABA. When either veratridine or 100 mM KCl were added to the infusion medium amino acid release was evoked although the extent of this varied from one amino acid to another. LTG (10 mg/kg) reduced veratridine-evoked release of all four amino acids studied, although this was most marked in the case of GLU. LTG had no effect on KCl-stimulated amino acid release. When given for up to 21 days (2 x 5 mg/kg/day), LTG had no effect on basal amino acid levels. In contrast, LTG demonstrated over the time period studied an increasingly inhibitory effect on veratridine-evoked amino acid release. This effect of the drug was proportionally much greater in the case of GLU than for the other three amino acids studied. Measurement of plasma, whole brain tissue and extracellular LTG showed that in each of these compartments, it had reached an apparent steady state within 4 days of commencement of treatment and appeared to mirror the neurochemical changes measured. Our estimate of plasma LTG indicates that during chronic study, this was well within the therapeutic range, suggesting that the current neurochemical observations are clinically relevant.
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Affiliation(s)
- Shagufta Ahmad
- Department of Pharmacology, The School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, Great Britain, United Kingdom
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Louzada PR, Paula Lima AC, Mendonca-Silva DL, Noël F, De Mello FG, Ferreira ST. Taurine prevents the neurotoxicity of beta-amyloid and glutamate receptor agonists: activation of GABA receptors and possible implications for Alzheimer's disease and other neurological disorders. FASEB J 2004; 18:511-8. [PMID: 15003996 DOI: 10.1096/fj.03-0739com] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Alzheimer's disease (AD) and several other neurological disorders have been linked to the overactivation of glutamatergic transmission and excitotoxicity as a common pathway of neuronal injury. The beta-amyloid peptide (Abeta) is centrally related to the pathogenesis of AD, and previous reports have demonstrated that the blockade of glutamate receptors prevents Abeta-induced neuronal death. We show that taurine, a beta-amino acid found at high concentrations in the brain, protects chick retinal neurons in culture against the neurotoxicity of Abeta and glutamate receptor agonists. The protective effect of taurine is not mediated by interaction with glutamate receptors, as demonstrated by binding studies using radiolabeled glutamate receptor ligands. The neuroprotective action of taurine is blocked by picrotoxin, an antagonist of GABA(A) receptors. GABA and the GABA(A) receptor agonists phenobarbital and melatonin also protect neurons against Abeta-induced neurotoxicity. These results suggest that activation of GABA receptors decreases neuronal vulnerability to excitotoxic damage and that pharmacological manipulation of the excitatory and inhibitory neurotransmitter tonus may protect neurons against a variety of insults. GABAergic transmission may represent a promising target for the treatment of AD and other neurological disorders in which excitotoxicity plays a relevant role.
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Affiliation(s)
- Paulo Roberto Louzada
- Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brasil
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25
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Hassel B, Boldingh KA, Narvesen C, Iversen EG, Skrede KK. Glutamate transport, glutamine synthetase and phosphate-activated glutaminase in rat CNS white matter. A quantitative study. J Neurochem 2003; 87:230-7. [PMID: 12969269 DOI: 10.1046/j.1471-4159.2003.01984.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Glutamatergic signal transduction occurs in CNS white matter, but quantitative data on glutamate uptake and metabolism are lacking. We report that the level of the astrocytic glutamate transporter GLT in rat fimbria and corpus callosum was approximately 35% of that in parietal cortex; uptake of [3H]glutamate was 24 and 43%, respectively, of the cortical value. In fimbria and corpus callosum levels of synaptic proteins, synapsin I and synaptophysin were 15-20% of those in cortex; the activities of glutamine synthetase and phosphate-activated glutaminase, enzymes involved in metabolism of transmitter glutamate, were 11-25% of cortical values, and activities of aspartate and alanine aminotransferases were 50-70% of cortical values. The glutamate level in fimbria and corpus callosum was 5-6 nmol/mg tissue, half the cortical value. These data suggest a certain capacity for glutamatergic neurotransmission. In optic and trigeminal nerves, [3H]glutamate uptake was < 10% of the cortical uptake. Formation of [14C]glutamate from [U-14C]glucose in fimbria and corpus callosum of awake rats was 30% of cortical values, in optic nerve it was 13%, illustrating extensive glutamate metabolism in white matter in vivo. Glutamate transporters in brain white matter may be important both physiologically and during energy failure when reversal of glutamate uptake may contribute to excitotoxicity.
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Affiliation(s)
- Bjørnar Hassel
- Norwegian Defence Research Establishment, Kjeller, Norway.
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Ketter TA, Manji HK, Post RM. Potential mechanisms of action of lamotrigine in the treatment of bipolar disorders. J Clin Psychopharmacol 2003; 23:484-95. [PMID: 14520126 DOI: 10.1097/01.jcp.0000088915.02635.e8] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Based on the mood-stabilizing properties of carbamazepine and valproate, new anticonvulsants have been explored for use in bipolar disorders. One such agent, lamotrigine, has a novel clinical profile in that it may "stabilize mood from below," as it appears to maximally impact depressive symptoms in bipolar disorders. In this paper, we review the mechanisms of action of lamotrigine in an effort to understand the basis of its distinctive clinical use in the management of bipolar disorders as well as its diverse antiseizure effects. We consider lamotrigine mechanisms, emphasizing commonalities and dissociations among actions of lamotrigine, older mood stabilizers, and other anticonvulsants. Although ion channel effects, especially sodium channel blockade, may importantly contribute to antiseizure effects, such actions may be less central to lamotrigine thymoleptic effects. Antiglutamatergic and neuroprotective actions are important candidate mechanisms for lamotrigine psychotropic effects. Lamotrigine has a variable profile in kindling and contingent tolerance experiments and does not appear to have robust gamma-aminobutyric acid or monoaminergic actions. Lamotrigine intracellular signaling effects warrant investigation. Although lamotrigine mechanisms overlap those of other mood-stabilizing anticonvulsants, important dissociations suggest candidate mechanisms, which could contribute to lamotrigine's distinctive psychotropic profile.
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Affiliation(s)
- Terence A Ketter
- Bipolar Disorders Clinic, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA.
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Abstract
The authors review the available literature on the preclinical and clinical studies involving GABAergic neurotransmission in mood disorders. Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter present almost exclusively in the central nervous system (CNS), distributed across almost all brain regions, and expressed in interneurons modulating local circuits. The role of GABAergic dysfunction in mood disorders was first proposed 20 years ago. Preclinical studies have suggested that GABA levels may be decreased in animal models of depression, and clinical studies reported low plasma and CSF GABA levels in mood disorder patients. Also, antidepressants, mood stabilizers, electroconvulsive therapy, and GABA agonists have been shown to reverse the depression-like behavior in animal models and to be effective in unipolar and bipolar patients by increasing brain GABAergic activity. The hypothesis of reduced GABAergic activity in mood disorders may complement the monoaminergic and serotonergic theories, proposing that the balance between multiple neurotransmitter systems may be altered in these disorders. However, low GABAergic cortical function may probably be a feature of a subset of mood disorder patients, representing a genetic susceptibility. In this paper, we discuss the status of GABAergic hypothesis of mood disorders and suggest possible directions for future preclinical and clinical research in this area.
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Affiliation(s)
- P Brambilla
- Biological Psychiatry Unit, IRCCS S Giovanni di Dio, Fatebenefratelli, Brescia, Italy.
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Isoherranen N, Yagen B, Spiegelstein O, Finnell RH, Merriweather M, Woodhead JH, Wlodarczyk B, White HS, Bialer M. Anticonvulsant activity, teratogenicity and pharmacokinetics of novel valproyltaurinamide derivatives in mice. Br J Pharmacol 2003; 139:755-64. [PMID: 12812999 PMCID: PMC1573897 DOI: 10.1038/sj.bjp.0705301] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2003] [Revised: 03/27/2003] [Accepted: 03/27/2003] [Indexed: 11/08/2022] Open
Abstract
1 The purpose of this study was to synthesize novel valproyltaurine (VTA) derivatives including valproyltaurinamide (VTD), N-methyl-valproyltaurinamide (M-VTD), N,N-dimethyl-valproyltaurinamide (DM-VTD) and N-isopropyl-valproyltaurinamide (I-VTD) and evaluate their structure-pharmacokinetic-pharmacodynamic relationships with respect to anticonvulsant activity and teratogenic potential. However, their hepatotoxic potential could not be evaluated. The metabolism and pharmacokinetics of these derivatives in mice were also studied. 2 VTA lacked anticonvulsant activity, but VTD, DM-VTD and I-VTD possessed anticonvulsant activity in the Frings audiogenic seizure susceptible mice (ED(50) values of 52, 134 and 126 mg kg(-1), respectively). 3 VTA did not have any adverse effect on the reproductive outcome in the Swiss Vancouver/Fnn mice following a single i.p. injection of 600 mg kg(-1) on gestational day (GD) 8.5. VTD (600 mg kg(-1) at GD 8.5) produced an increase in embryolethality, but unlike valproic acid, it did not induce congenital malformations. DM-VTD and I-VTD (600 mg kg(-1) at GD 8.5) produced a significant increase in the incidence of gross malformations. The incidence of birth defects increased when the length of the alkyl substituent or the degree of N-alkylation increased. 4 In mice, N-alkylated VTDs underwent metabolic N-dealkylation to VTD. DM-VTD was first biotransformed to M-VTD and subsequently to VTD. I-VTD's fraction metabolized to VTD was 29%. The observed metabolic pathways suggest that active metabolites may contribute to the anticonvulsant activity of the N-alkylated VTDs and reactive intermediates may be formed during their metabolism. In mice, VTD had five to 10 times lower clearance (CL), and three times longer half-life than I-VTD and DM-VTD, making it a more attractive compound than DM-VTD and I-VTD for further development. VTD's extent of brain penetration was only half that observed for the N-alkylated taurinamides suggesting that it has a higher intrinsic activity that DM-VTD and I-VTD. 5 In conclusion, from this series of compounds, although VTD caused embryolethality, this compound emerged as the most promising new antiepileptic drug, having a preclinical spectrum characterized by the highest anticonvulsant potential, lowest potential for teratogenicity and favorable pharmacokinetics.
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Affiliation(s)
- Nina Isoherranen
- Department of Pharmaceutics, School of Pharmacy, Hebrew University of Jerusalem, Israel
| | - Boris Yagen
- Department of Natural Products and Medicinal Chemistry, School of Pharmacy, Hebrew University of Jerusalem, Israel
- David R. Bloom Center for Pharmacy, The Hebrew University of Jerusalem, Israel
| | - Ofer Spiegelstein
- Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX, U.S.A
| | - Richard H Finnell
- Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX, U.S.A
| | - Michelle Merriweather
- Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX, U.S.A
| | - Jose H Woodhead
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, U.S.A
| | - Bogdan Wlodarczyk
- Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, TX, U.S.A
| | - H Steve White
- Anticonvulsant Drug Development Program, University of Utah, Salt Lake City, UT, U.S.A
| | - Meir Bialer
- Department of Pharmaceutics, School of Pharmacy, Hebrew University of Jerusalem, Israel
- David R. Bloom Center for Pharmacy, The Hebrew University of Jerusalem, Israel
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Rainesalo S, Saransaari P, Peltola J, Keränen T. Uptake of GABA and activity of GABA-transaminase in platelets from epileptic patients. Epilepsy Res 2003; 53:233-9. [PMID: 12694932 DOI: 10.1016/s0920-1211(03)00030-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to assess the activity of GABA-transaminase (GABA-T) and the kinetic parameters of GABA uptake in platelets from patients with distinct epileptic syndromes. We studied 14 patients with juvenile myoclonic epilepsy (JME), 19 patients with refractory localization-related epilepsy (RLE) and 20 healthy volunteers who were matched for age and sex. Acute effects of valproate (VPA) and lamotrigine (LTG) on the uptake of GABA and the activity of GABA-T in platelets in vitro were also analyzed. The mean activity of GABA-T in JME patients was significantly higher than in control subjects, whereas RLE patients did not significantly differ from controls. The capacity of GABA uptake was least in JME patients, intermediate in RLE patients and highest in controls. In vitro VPA (concentrations 150-1200 microM) or LTG (concentrations 1-100 microM) had no significant effects on GABA uptake. Our results indicate marked differences in the platelet uptake of GABA and the activity of catabolic enzyme GABA-T between patients with generalized and localization-related epileptic syndromes. The observed peripheral alterations may indicate an impairment in the function of brain GABAergic systems.
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Affiliation(s)
- Sirpa Rainesalo
- Brain Research Center, Medical School, University of Tampere, Tampere FIN-33014, Finland.
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Zhang ZJ, Russell S, Obeng K, Postma T, Obrocea G, Weiss SRB, Post RM. Coadministration of gabapentin or MK-801 with lamotrigine slows tolerance to its anticonvulsant effects on kindled seizures. Pharmacol Biochem Behav 2003; 74:565-71. [PMID: 12543220 DOI: 10.1016/s0091-3057(02)01035-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The development of tolerance to therapeutic effects of antiepileptic drugs can be a problem in the treatment of epilepsy, bipolar disorder, and pain syndromes. In the present study, acute treatment with the new antiepileptic drug lamotrigine (LTG, 15 mg/kg) markedly suppressed seizure stage and seizure duration in amygdala-kindled rats; but this antiseizure effect was rapidly lost following 4-8 days of repeated treatment. When gabapentin (GBP, 20 mg/kg) was coadministered with LTG, the ability of LTG to suppress seizure stage, seizure duration, and after-discharge (AD) duration was markedly extended. In addition, GBP coadministration with LTG decreased the number of animals that developed LTG-related running fits (Stage 6 seizures) and lengthened the number of days required to develop running fits or complete tolerance. Neither acute nor repeated treatment with MK-801 (0.3 mg/kg), a noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, had effects on kindled seizures. However, cotreatment with MK-801 markedly extended the anticonvulsant effects of LTG on the three seizure indices and reduced running fits. These data indicate that cotreatment with either GBP or MK-801 slows tolerance development to the anticonvulsant effects of LTG on kindled seizures. Therapeutic implications of the present study remain to be explored.
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Affiliation(s)
- Zhang-Jin Zhang
- Department of Psychiatry, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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31
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Castel-Branco MM, Figueiredo IV, Falcão AC, Macedo TRA, Caramona MM. Influence of administration vehicles and drug formulations on the pharmacokinetic profile of lamotrigine in rats. Fundam Clin Pharmacol 2002; 16:331-6. [PMID: 12602457 DOI: 10.1046/j.1472-8206.2002.00096.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Given that administration vehicles and drug formulations can affect drug bioavailability, their influence on the pharmacokinetic profile of lamotrigine (LTG), a new-generation anti-epileptic drug, was studied in rats. Three different formulations administered intraperitoneally at a dose of 10 mg/kg were used: (1) LTG suspended in a 0.25% methylcelulose solution, (2) LTG dissolved in a 50% propylene glycol solution, and (3) LTG isethionate dissolved in distilled water. Plasma and brain homogenate levels were determined in order to evaluate vehicle-dependent drug absorption. The results demonstrated rapid absorption of LTG when it was administered as an aqueous solution, in contrast to a slower and more erratic absorption after the injection of either the lipophilic solution or the suspension. A plasma peak was achieved 15 min post-dose with the aqueous solution, with a brain peak being achieved 15 min later, while with the other formulations both plasma and brain homogenate peaks were reached 2 h after LTG administration. This study suggests that LTG isethionate dissolved in distilled water is the most suitable formulation for successful LTG pharmacokinetic studies in rats.
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Affiliation(s)
- M M Castel-Branco
- Laboratory of Pharmacology, Faculty of Pharmacy, Coimbra University, Coimbra, Portugal
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Foos TM, Wu JY. The role of taurine in the central nervous system and the modulation of intracellular calcium homeostasis. Neurochem Res 2002; 27:21-6. [PMID: 11926272 DOI: 10.1023/a:1014890219513] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The effects of taurine in the mammalian nervous system are numerous and varied. There has been great difficulty in determining the specific targets of taurine action. The authors present a review of accepted taurine action and highlight recent discoveries regarding taurine and calcium homeostasis in neurons. In general there is a consensus that taurine is a powerful agent in regulating and reducing the intracellular calcium levels in neurons. After prolonged L-glutamate stimulation, neurons lose the ability to effectively regulate intracellular calcium. This condition can lead to acute swelling and lysis of the cell, or culminate in apoptosis. Under these conditions, significant amounts of taurine (mM range) are released from the excited neuron. This extracellular taurine acts to slow the influx of calcium into the cytosol through both transmembrane ion transporters and intracellular storage pools. Two specific targets of taurine action are discussed: Na(+)-Ca2+ exchangers, and metabotropic receptors mediating phospholipase-C.
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Affiliation(s)
- Todd M Foos
- Department of Molecular Biosciences, University of Kansas, Lawrence 66045, USA
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