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Dudarenko MV, Pozdnyakova NG. Perinatal hypoxia and thalamus brain region: increased efficiency of antiepileptic drug levetiracetam to inhibit GABA release from nerve terminals. UKRAINIAN BIOCHEMICAL JOURNAL 2022. [DOI: 10.15407/ubj94.05.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Levetiracetam (LV), 2S-(2-oxo-1-pyrrolidiny1) butanamide, is an antiepileptic drug. The exact mechanisms of anticonvulsant effects of LV remain unclear. In this study, rats (Wistar strain) underwent hypoxia and seizures at the age of 10–12 postnatal days (pd). [3H]GABA release was analysed in isolated from thalamus nerve terminals (synaptosomes) during development at the age of pd 17–19 and pd 24–26 (infantile stage), pd 38–40 (puberty) and pd 66–73 (young adults) in control and after perinatal hypoxia. The extracellular level of [3H]GABA in the preparation of thalamic synaptosomes increased during development at the age of pd 38–40 and pd 66–73 as compared to earlier ones. LV did not influence the extracellular level of [3H]GABA in control and after perinatal hypoxia at all studied ages. Exocytotic [3H]GABA release in control increased at the age of pd 24–26 as compared to pd 17–19. After hypoxia, exocytotic [3H]GABA release from synaptosomes also increased during development. LV elevated [3H]GABA release from thalamic synaptosomes at the age of pd 66–73 after hypoxia and during blockage of GABA uptake by NO-711 only. LV realizes its antiepileptic effects at the presynaptic site through an increase in exocytotic release of [3H]GABA in thalamic synaptosomes after perinatal hypoxia at pd 66–73. LV exhibited a more significant effect in thalamic synaptosomes after perinatal hypoxia than in control ones. The action of LV is age-dependent, and the drug was inert at the infantile stage that can be useful for an LV application strategy in child epilepsy therapy. Keywords: brain development, exocytosis, GABA, levetiracetam, perinatal hypoxia, thalamic synaptosomes
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Shimizu-Okabe C, Kobayashi S, Kim J, Kosaka Y, Sunagawa M, Okabe A, Takayama C. Developmental Formation of the GABAergic and Glycinergic Networks in the Mouse Spinal Cord. Int J Mol Sci 2022; 23:ijms23020834. [PMID: 35055019 PMCID: PMC8776010 DOI: 10.3390/ijms23020834] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 12/15/2022] Open
Abstract
Gamma-aminobutyric acid (GABA) and glycine act as inhibitory neurotransmitters. Three types of inhibitory neurons and terminals, GABAergic, GABA/glycine coreleasing, and glycinergic, are orchestrated in the spinal cord neural circuits and play critical roles in regulating pain, locomotive movement, and respiratory rhythms. In this study, we first describe GABAergic and glycinergic transmission and inhibitory networks, consisting of three types of terminals in the mature mouse spinal cord. Second, we describe the developmental formation of GABAergic and glycinergic networks, with a specific focus on the differentiation of neurons, formation of synapses, maturation of removal systems, and changes in their action. GABAergic and glycinergic neurons are derived from the same domains of the ventricular zone. Initially, GABAergic neurons are differentiated, and their axons form synapses. Some of these neurons remain GABAergic in lamina I and II. Many GABAergic neurons convert to a coreleasing state. The coreleasing neurons and terminals remain in the dorsal horn, whereas many ultimately become glycinergic in the ventral horn. During the development of terminals and the transformation from radial glia to astrocytes, GABA and glycine receptor subunit compositions markedly change, removal systems mature, and GABAergic and glycinergic action shifts from excitatory to inhibitory.
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Affiliation(s)
- Chigusa Shimizu-Okabe
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Shiori Kobayashi
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Jeongtae Kim
- Department of Anatomy, Kosin University College of Medicine, Busan 49267, Korea;
| | - Yoshinori Kosaka
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Masanobu Sunagawa
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
| | - Akihito Okabe
- Department of Nutritional Science, Faculty of Health and Welfare, Seinan Jo Gakuin University, Fukuoka 803-0835, Japan;
| | - Chitoshi Takayama
- Department of Molecular Anatomy, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara 903-0215, Japan; (C.S.-O.); (S.K.); (Y.K.); (M.S.)
- Correspondence: ; Tel.: +81-98-895-1103 or +81-895-1405
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Bakalar D, Sweat S, Drossel G, Jiang SZ, Samal BS, Stroth N, Xu W, Zhang L, Zhang H, Eiden LE. Relationships between constitutive and acute gene regulation, and physiological and behavioral responses, mediated by the neuropeptide PACAP. Psychoneuroendocrinology 2022; 135:105447. [PMID: 34741979 PMCID: PMC8900973 DOI: 10.1016/j.psyneuen.2021.105447] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/10/2021] [Accepted: 10/08/2021] [Indexed: 01/03/2023]
Abstract
Since the advent of gene knock-out technology in 1987, insight into the role(s) of neuropeptides in centrally- and peripherally-mediated physiological regulation has been gleaned by examining altered physiological functioning in mammals, predominantly mice, after genetic editing to produce animals deficient in neuropeptides or their cognate G-protein coupled receptors (GPCRs). These results have complemented experiments involving infusion of neuropeptide agonists or antagonists systemically or into specific brain regions. Effects of gene loss are often interpreted as indicating that the peptide and its receptor(s) are required for the physiological or behavioral responses elicited in wild-type mice at the time of experimental examination. These interpretations presume that peptide/peptide receptor gene deletion affects only the expression of the peptide/receptor itself, and therefore impacts physiological events only at the time at which the experiment is conducted. A way to support 'real-time' interpretations of neuropeptide gene knock-out is to demonstrate that the wild-type transcriptome, except for the deliberately deleted gene(s), in tissues of interest, is preserved in the knock-out mouse. Here, we show that there is a cohort of genes (constitutively PACAP-Regulated Genes, or cPRGs) whose basal expression is affected by constitutive knock-out of the Adcyap1 gene in C57Bl6/N mice, and additional genes whose expression in response to physiological challenge, in adults, is altered or impaired in the absence of PACAP expression (acutely PACAP-Regulated Genes, or aPRGs). Distinguishing constitutive and acute transcriptomic effects of neuropeptide deficiency on physiological function and behavior in mice reveals alternative mechanisms of action, and changing functions of neuropeptides, throughout the lifespan.
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Affiliation(s)
- Dana Bakalar
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Sean Sweat
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Gunner Drossel
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Sunny Z. Jiang
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Babru S. Samal
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Nikolas Stroth
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Wenqin Xu
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Limei Zhang
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA,Department of Physiology, Autonomous National University of Mexico (UNAM) Medical School, Mexico City, Mexico
| | - Haiying Zhang
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA
| | - Lee E. Eiden
- Section on Molecular Neuroscience, National Institute of Mental Heath - Intramural Research Program, Bethesda, MD. NIH, USA,Correspondence Lee E. Eiden, Ph.D., Section on Molecular Neuroscience, National Institute of Mental Heath – Intramural Research Program, Bethesda, MD. NIH, USA, Phone: +13014964110,
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Gorski K, Spoljaric A, Nyman TA, Kaila K, Battersby BJ, Lehesjoki AE. Quantitative Changes in the Mitochondrial Proteome of Cerebellar Synaptosomes From Preclinical Cystatin B-Deficient Mice. Front Mol Neurosci 2020; 13:570640. [PMID: 33281550 PMCID: PMC7691638 DOI: 10.3389/fnmol.2020.570640] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/21/2020] [Indexed: 12/04/2022] Open
Abstract
Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is a neurodegenerative disorder caused by loss-of-function mutations in the cystatin B (CSTB) gene. Progression of the clinical symptoms in EPM1 patients, including stimulus-sensitive myoclonus, tonic-clonic seizures, and ataxia, are well described. However, the cellular dysfunction during the presymptomatic phase that precedes the disease onset is not understood. CSTB deficiency leads to alterations in GABAergic signaling, and causes early neuroinflammation followed by progressive neurodegeneration in brains of a mouse model, manifesting as progressive myoclonus and ataxia. Here, we report the first proteome atlas from cerebellar synaptosomes of presymptomatic Cstb-deficient mice, and propose that early mitochondrial dysfunction is important to the pathogenesis of altered synaptic function in EPM1. A decreased sodium- and chloride dependent GABA transporter 1 (GAT-1) abundance was noted in synaptosomes with CSTB deficiency, but no functional difference was seen between the two genotypes in electrophysiological experiments with pharmacological block of GAT-1. Collectively, our findings provide novel insights into the early onset and pathogenesis of CSTB deficiency, and reveal greater complexity to the molecular pathogenesis of EPM1.
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Affiliation(s)
- Katarin Gorski
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Albert Spoljaric
- Molecular and Integrative Biosciences, and Neuroscience Center (HiLIFE), Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Tuula A Nyman
- Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - Kai Kaila
- Molecular and Integrative Biosciences, and Neuroscience Center (HiLIFE), Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | | | - Anna-Elina Lehesjoki
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
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Nam SM, Seo JS, Nahm SS, Chang BJ. Effects of ascorbic acid treatment on developmental alterations in calcium-binding proteins and gamma-aminobutyric acid transporter 1 in the cerebellum of lead-exposed rats during pregnancy and lactation. J Toxicol Sci 2020; 44:799-809. [PMID: 31708536 DOI: 10.2131/jts.44.799] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In the present study, we investigated the effects of lead (Pb) and ascorbic acid co-administration on rat cerebellar development. Female rats were randomly divided into the following groups: control, Pb, and Pb plus ascorbic acid (PA) groups. From one week prior to mating, female rats were administered Pb (0.3% Pb acetate in drinking water) and ascorbic acid (100 mg/kg, oral intubation). The chemical administration was stopped on postnatal day 21 when the morphology of the offspring's cerebellum is similar to that of the adult brain. The blood Pb level was significantly increased following long-term Pb exposure. Ascorbic acid reduced Pb levels in the dams and offspring. Nissl staining demonstrated that the number of Purkinje cells was significantly reduced following Pb exposure, while ascorbic acid ameliorated this effect in the cerebellum of the offspring. Calcium-binding proteins, such as calbindin, calretinin, and parvalbumin were commonly expressed in Purkinje cells, and Pb exposure and ascorbic acid treatment resulted in similar patterns of change, namely Pb-induced impairment and ascorbic acid-mediated amelioration. The gamma-aminobutyric acid transporter 1 (GABAT1) is expressed in the pinceau structure where the somata of Purkinje cells are entwined in inhibitory synapses. The number of GABAT1-immunoreactive synapses was reduced following Pb exposure, and ascorbic acid co-treatment prevented this effect in the cerebellar cortex. Therefore, it can be concluded that ascorbic acid supplementation to mothers during gestation and lactation may have potential preventive effects against Pb-induced impairments in the developing cerebellum via protection of inhibitory neurons and synapses.
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Affiliation(s)
- Sung Min Nam
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Korea.,College of Veterinary Medicine and Veterinary Science Research Institute, Konkuk University, Korea
| | - Jin Seok Seo
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Korea
| | - Sang-Soep Nahm
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Korea.,College of Veterinary Medicine and Veterinary Science Research Institute, Konkuk University, Korea
| | - Byung-Joon Chang
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Korea.,College of Veterinary Medicine and Veterinary Science Research Institute, Konkuk University, Korea
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Nam SM, Choi SH, Cho HJ, Seo JS, Choi M, Nahm SS, Chang BJ, Nah SY. Ginseng Gintonin Attenuates Lead-Induced Rat Cerebellar Impairments during Gestation and Lactation. Biomolecules 2020; 10:biom10030385. [PMID: 32131481 PMCID: PMC7175158 DOI: 10.3390/biom10030385] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 02/26/2020] [Accepted: 02/26/2020] [Indexed: 12/13/2022] Open
Abstract
Gintonin, a novel ginseng-derived lysophosphatidic acid receptor ligand, improves brain functions and protects neurons from oxidative stress. However, little is known about the effects of gintonin against Pb-induced brain maldevelopment. We investigated the protective effects of gintonin on the developing cerebellum after prenatal and postnatal Pb exposure. Pregnant female rats were randomly divided into three groups: control, Pb (0.3% Pb acetate in drinking water), and Pb plus gintonin (100 mg/kg, p.o.). Blood Pb was increased in dams and pups; gintonin treatment significantly decreased blood Pb. On postnatal day 21, the number of degenerating Purkinje cells was remarkably increased while the number of calbindin-, GAD67-, NMDAR1-, LPAR1-immunoreactive intact Purkinje cells, and GABA transporter 1-immunoreactive pinceau structures were significantly reduced in Pb-exposed offspring. Following Pb exposure, gintonin ameliorated cerebellar degenerative effects, restored increased pro-apoptotic Bax, and decreased anti-apoptotic Bcl2. Gintonin treatment attenuated Pb-induced accumulation of oxidative stress (Nrf2 and Mn-SOD) and inflammation (IL-1β and TNFα,), restoring the decreased cerebellar BDNF and Sirt1. Gintonin ameliorated Pb-induced impairment of myelin basic protein-immunoreactive myelinated fibers of Purkinje cells. Gintonin attenuated Pb-induced locomotor dysfunctions. The present study revealed the ameliorating effects of gintonin against Pb, suggesting the potential use of gintonin as a preventive agent in Pb poisoning during pregnancy and lactation.
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Affiliation(s)
- Sung Min Nam
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.M.N.); (J.S.S.); (M.C.); (S.-S.N.); (B.-J.C.)
| | - Sun-Hye Choi
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.-H.C.); (H.-J.C.)
| | - Hee-Jung Cho
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.-H.C.); (H.-J.C.)
| | - Jin Seok Seo
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.M.N.); (J.S.S.); (M.C.); (S.-S.N.); (B.-J.C.)
| | - Minsuk Choi
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.M.N.); (J.S.S.); (M.C.); (S.-S.N.); (B.-J.C.)
| | - Sang-Soep Nahm
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.M.N.); (J.S.S.); (M.C.); (S.-S.N.); (B.-J.C.)
| | - Byung-Joon Chang
- Department of Anatomy, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.M.N.); (J.S.S.); (M.C.); (S.-S.N.); (B.-J.C.)
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (S.-H.C.); (H.-J.C.)
- Correspondence: ; Tel.: +82-2-450-4154
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Pozdnyakova N, Dudarenko M, Borisova T. Age-Dependency of Levetiracetam Effects on Exocytotic GABA Release from Nerve Terminals in the Hippocampus and Cortex in Norm and After Perinatal Hypoxia. Cell Mol Neurobiol 2019; 39:701-714. [PMID: 31006090 DOI: 10.1007/s10571-019-00676-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/10/2019] [Indexed: 10/27/2022]
Abstract
Perinatal hypoxia can lead to multiple chronic neurological deficits, e.g., mental retardation, behavioral abnormalities, and epilepsy. Levetiracetam (LEV), 2S-(2-oxo-1-pyrrolidiny1) butanamide, is an anticonvulsant drug with proven efficiency in treating patients with focal and generalized seizures. Rats were underwent hypoxia and seizures at the age of 10-12 postnatal days (pd). The ambient level and depolarization-induced exocytotic release of [3H]GABA (γ-aminobutyric acid) were analyzed in nerve terminals in the hippocampus and cortex during development at the age of pd 17-19 and pd 24-26 (infantile stage), pd 38-40 (puberty) and pd 66-73 (young adults) in norm and after perinatal hypoxia. LEV had no effects on the ambient [3H]GABA level. The latter increased during development and was further elevated after perinatal hypoxia in nerve terminals in the hippocampus during the whole period and in the cortex in young adults. Exocytotic [3H]GABA release from nerve terminals increased after perinatal hypoxia during development in the hippocampus and cortex, however this effect was preserved at all ages during blockage of GABA transporters by NO-711 in the hippocampus only. LEV realized its anticonvulsant effects at the presynaptic site through an increase in exocytotic release of GABA. LEV exerted more significant effect after perinatal hypoxia than in norm. Action of LEV was strongly age-dependent and can be registered in puberty and young adults, but the drug was inert at the infantile stage.
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Affiliation(s)
- Natalia Pozdnyakova
- The Department of Neurochemistry, Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Str, Kiev, 01030, Ukraine
| | - Marina Dudarenko
- The Department of Neurochemistry, Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Str, Kiev, 01030, Ukraine
| | - Tatiana Borisova
- The Department of Neurochemistry, Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovicha Str, Kiev, 01030, Ukraine.
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Pozdnyakova N. Consequences of perinatal hypoxia in developing brain: Changes in GABA transporter functioning in cortical, hippocampal and thalamic rat nerve terminals. Int J Dev Neurosci 2017; 63:1-7. [DOI: 10.1016/j.ijdevneu.2017.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 06/26/2017] [Accepted: 09/05/2017] [Indexed: 12/15/2022] Open
Affiliation(s)
- Natalia Pozdnyakova
- Department of NeurochemistryPalladin Institute of Biochemistry, National Academy of Sciences of UkraineLeontovicha Str. 9Kiev01030Ukraine
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Sotelo C. Molecular layer interneurons of the cerebellum: developmental and morphological aspects. CEREBELLUM (LONDON, ENGLAND) 2015; 14:534-56. [PMID: 25599913 DOI: 10.1007/s12311-015-0648-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
During the past 25 years, our knowledge on the development of basket and stellate cells (molecular layer interneurons [MLIs]) has completely changed, not only regarding their origin from the ventricular zone, corresponding to the primitive cerebellar neuroepithelium, instead of the external granular layer, but above all by providing an almost complete account of the genetic regulations (transcription factors and other genes) involved in their differentiation and synaptogenesis. Moreover, it has been shown that MLIs' precursors (dividing neuroblasts) and not young postmitotic neurons, as in other germinal neuroepithelia, leave the germinative zone and migrate all along a complex and lengthy path throughout the presumptive cerebellar white matter, which provides suitable niches exerting epigenetic influences on their ultimate neuronal identities. Recent studies carried out on the anatomical-functional properties of adult MLIs emphasize the importance of these interneurons in regulating PC inhibition, and point out the crucial role played by electrical synaptic transmission between MLIs as well as ephaptic interactions between them and Purkinje cells at the pinceaux level, in the regulation of this inhibition.
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Affiliation(s)
- Constantino Sotelo
- INSERM, UMRS_U968, Institut de la Vision, 17 Rue Moreau, Paris, 75012, France.
- Institut de la Vision, Sorbonne Université, UPMC Univ Paris 06, Paris, 75012, France.
- CNRS, UMR_7210, Paris, 75012, France.
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Miguel Hernández (UMH), Avenida Ramón y Cajal s/n, 03550, San Juan de Alicante, Spain.
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Stephan J, Friauf E. Functional analysis of the inhibitory neurotransmitter transporters GlyT1, GAT-1, and GAT-3 in astrocytes of the lateral superior olive. Glia 2014; 62:1992-2003. [PMID: 25103283 DOI: 10.1002/glia.22720] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 01/03/2023]
Abstract
Neurotransmitter clearance from the synaptic cleft is a major function of astrocytes and requires neurotransmitter transporters. In the rodent lateral superior olive (LSO), a conspicuous auditory brainstem center, both glycine and GABA mediate synaptic inhibition. However, the main inhibitory input from the medial nucleus of the trapezoid body (MNTB) appears to be glycinergic by postnatal day (P) 14, when circuit maturation is almost accomplished. Using whole-cell patch-clamp recordings at P3-20, we analyzed glycine transporters (GlyT1) and GABA transporters (GAT-1, GAT-3) in mouse LSO astrocytes, emphasizing on their developmental regulation. Application of glycine or GABA induced a dose- and age-dependent inward current and a respective depolarization. The GlyT1-specific inhibitor sarcosine reduced the maximal glycine-induced current (IGly (max) ) by about 60%. The GAT-1 and GAT-3 antagonists NO711 and SNAP5114, respectively, reduced the maximal GABA-induced current (IGABA (max) ) by about 35%. Furthermore, [Cl(-) ]o reduction decreased IGly (max) and IGABA (max) by about 85 to 95%, showing the Cl(-) dependence of GlyT and GAT. IGABA (max) was stronger than IGly (max) , and the ratio increased developmentally from 1.6-fold to 3.7-fold. Together, our results demonstrate the functional presence of the three inhibitory neurotransmitter transporters GlyT1, GAT-1, and GAT-3 in LSO astrocytes. Furthermore, the uptake capability for GABA was higher than for glycine, pointing toward eminent GABAergic signaling in the LSO. GABA may originate from another source than the MNTB-LSO synapses, namely from another projection or from reversal of astrocytic GATs. Thus, neuronal signaling in the LSO appears to be more versatile than previously thought. GLIA 2014;62:1992-2003.
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Affiliation(s)
- Jonathan Stephan
- Department of Biology, Animal Physiology Group, University of Kaiserslautern, Kaiserslautern, Germany
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Characteristic development of the GABA-removal system in the mouse spinal cord. Neuroscience 2014; 262:129-42. [DOI: 10.1016/j.neuroscience.2013.12.066] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 12/28/2013] [Accepted: 12/31/2013] [Indexed: 11/24/2022]
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Yamashita A, Hamada A, Suhara Y, Kawabe R, Yanase M, Kuzumaki N, Narita M, Matsui R, Okano H, Narita M. Astrocytic activation in the anterior cingulate cortex is critical for sleep disorder under neuropathic pain. Synapse 2014; 68:235-47. [DOI: 10.1002/syn.21733] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 01/09/2014] [Indexed: 01/21/2023]
Affiliation(s)
- Akira Yamashita
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Asami Hamada
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Yuki Suhara
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Rui Kawabe
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Makoto Yanase
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Naoko Kuzumaki
- Department of Physiology; Keio University School of Medicine; 35 Shinanomachi Shinjuku-ku Tokyo 160-8582 Japan
| | - Michiko Narita
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
| | - Ryosuke Matsui
- Department of Molecular and Systems Biology; Graduate School of Biostudies, Kyoto University; Yoshida Sakyo-ku Kyoto 606-8501 Japan
| | - Hideyuki Okano
- Department of Physiology; Keio University School of Medicine; 35 Shinanomachi Shinjuku-ku Tokyo 160-8582 Japan
| | - Minoru Narita
- Department of Pharmacology; Hoshi University School of Pharmacy and Pharmaceutical Sciences; 2-4-41 Ebara Shinagawa-ku Tokyo 142-8501 Japan
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Egawa K, Fukuda A. Pathophysiological power of improper tonic GABA(A) conductances in mature and immature models. Front Neural Circuits 2013; 7:170. [PMID: 24167475 PMCID: PMC3807051 DOI: 10.3389/fncir.2013.00170] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 09/28/2013] [Indexed: 11/25/2022] Open
Abstract
High-affinity extrasynaptic gamma-aminobutyric acid A (GABAA) receptors are tonically activated by low and consistent levels of ambient GABA, mediating chronic inhibition against neuronal excitability (tonic inhibition) and the modulation of neural development. Synaptic (phasic) inhibition is spatially and temporally precise compared with tonic inhibition, which provides blunt yet strong integral inhibitory force by shunting electrical signaling. Although effects of acute modification of tonic inhibition are known, its pathophysiological significance remains unclear because homeostatic regulation of neuronal excitability can compensate for long-term deficit of extrasynaptic GABAA receptor activation. Nevertheless, tonic inhibition is of great interest for its pathophysiological involvement in central nervous system (CNS) diseases and thus as a therapeutic target. Together with the development of experimental models for various pathological states, recent evidence demonstrates such pathological involvements of tonic inhibition in neuronal dysfunction. This review focuses on the recent progress of tonic activation of GABAA conductance on the development and pathology of the CNS. Findings indicate that neuronal function in various brain regions are exacerbated with a gain or loss of function of tonic inhibition by GABA spillover. Disturbance of tonic GABAA conductance mediated by non-synaptic ambient GABA may result in brain mal-development. Therefore, various pathological states (epilepsy, motor dysfunctions, psychiatric disorders, and neurodevelopmental disorders) may be partly attributable to abnormal tonic GABAA conductances. Thus, the tone of tonic conductance and level of ambient GABA may be precisely tuned to maintain the regular function and development of the CNS. Therefore, receptor expression and factors for regulating the ambient GABA concentration are highlighted to gain a deeper understanding of pathology and therapeutic strategy for CNS diseases.
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Affiliation(s)
- Kiyoshi Egawa
- Department of Neurology, Massachusetts General Hospital Charlestown, MA, USA ; Department of Pediatrics, Hokkaido University Graduate School of Medicine Sapporo, Japan
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Egawa K, Kitagawa K, Inoue K, Takayama M, Takayama C, Saitoh S, Kishino T, Kitagawa M, Fukuda A. Decreased tonic inhibition in cerebellar granule cells causes motor dysfunction in a mouse model of Angelman syndrome. Sci Transl Med 2013; 4:163ra157. [PMID: 23220633 DOI: 10.1126/scitranslmed.3004655] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Angelman syndrome is a neurodevelopmental disorder caused by loss of function of the UBE3A gene encoding a ubiquitin E3 ligase. Motor dysfunction is a characteristic feature of Angelman syndrome, but neither the mechanisms of action nor effective therapeutic strategies have yet been elucidated. We report that tonic inhibition is specifically decreased in cerebellar granule cells of Ube3a-deficient mice, a model of Angelman syndrome. As a mechanism underlying this decrease in tonic inhibition, we show that Ube3a controls degradation of γ-aminobutyric acid (GABA) transporter 1 (GAT1) and that deficiency of Ube3a induces a surplus of GAT1 that results in a decrease in GABA concentrations in the extrasynaptic space. Administering low doses of 4,5,6,7-tetrahydroisothiazolo-[5,4-c]pyridin-3-ol (THIP), a selective extrasynaptic GABA(A) receptor agonist, improves the abnormal firing properties of a population of Purkinje cells in cerebellar brain slices and reduces cerebellar ataxia in Ube3a-deficient mice in vivo. These results suggest that pharmacologically increasing tonic inhibition may be a useful strategy for alleviating motor dysfunction in Angelman syndrome.
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Affiliation(s)
- Kiyoshi Egawa
- Department of Neurophysiology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan.
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Developmental switching of perisomatic innervation from climbing fibers to basket cell fibers in cerebellar Purkinje cells. J Neurosci 2012; 31:16916-27. [PMID: 22114262 DOI: 10.1523/jneurosci.2396-11.2011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In early postnatal development, perisomatic innervation of cerebellar Purkinje cells (PCs) switches from glutamatergic climbing fibers (CFs) to GABAergic basket cell fibers (BFs). Here we examined the switching process in C57BL/6 mice. At postnatal day 7 (P7), most perisomatic synapses were formed by CFs on to somatic spines. The density of CF-spine synapses peaked at P9, when pericellular nest around PCs by CFs was most developed, and CF-spine synapses constituted 88% of the total perisomatic synapses. Thereafter, CF-spine synapses dropped to 63% at P12, 6% at P15, and <1% at P20, whereas BF synapses increased reciprocally. During the switching period, a substantial number of BF synapses existed as BF-spine synapses (37% of the total perisomatic synapses at P15), and free spines surrounded by BFs or Bergmann glia also emerged. By P20, BF-spine synapses and free spines virtually disappeared, and BF-soma synapses became predominant (88%), thus attaining the adult pattern of perisomatic innervation. Parallel with the presynaptic switching, postsynaptic receptor phenotype also switched from glutamatergic to GABAergic. In the active switching period, particularly at P12, fragmental clusters of AMPA-type glutamate receptor were juxtaposed with those of GABA(A) receptor. When examined with serial ultrathin sections, immunogold labeling for glutamate and GABA(A) receptors was often clustered beneath single BF terminals. These results suggest that a considerable fraction of somatic spines is succeeded from CFs to BFs and Bergmann glia in the early postnatal period, and that the switching of postsynaptic receptor phenotypes mainly proceeds under the coverage of BF terminals.
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Narita M, Niikura K, Nanjo-Niikura K, Narita M, Furuya M, Yamashita A, Saeki M, Matsushima Y, Imai S, Shimizu T, Asato M, Kuzumaki N, Okutsu D, Miyoshi K, Suzuki M, Tsukiyama Y, Konno M, Yomiya K, Matoba M, Suzuki T. Sleep disturbances in a neuropathic pain-like condition in the mouse are associated with altered GABAergic transmission in the cingulate cortex. Pain 2011; 152:1358-1372. [DOI: 10.1016/j.pain.2011.02.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 02/04/2011] [Accepted: 02/07/2011] [Indexed: 11/17/2022]
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Le-Corronc H, Rigo JM, Branchereau P, Legendre P. GABA(A) receptor and glycine receptor activation by paracrine/autocrine release of endogenous agonists: more than a simple communication pathway. Mol Neurobiol 2011; 44:28-52. [PMID: 21547557 DOI: 10.1007/s12035-011-8185-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 04/14/2011] [Indexed: 02/04/2023]
Abstract
It is a common and widely accepted assumption that glycine and GABA are the main inhibitory transmitters in the central nervous system (CNS). But, in the past 20 years, several studies have clearly demonstrated that these amino acids can also be excitatory in the immature central nervous system. In addition, it is now established that both GABA receptors (GABARs) and glycine receptors (GlyRs) can be located extrasynaptically and can be activated by paracrine release of endogenous agonists, such as GABA, glycine, and taurine. Recently, non-synaptic release of GABA, glycine, and taurine gained further attention with increasing evidence suggesting a developmental role of these neurotransmitters in neuronal network formation before and during synaptogenesis. This review summarizes recent knowledge about the non-synaptic activation of GABA(A)Rs and GlyRs, both in developing and adult CNS. We first present studies that reveal the functional specialization of both non-synaptic GABA(A)Rs and GlyRs and we discuss the neuronal versus non-neuronal origin of the paracrine release of GABA(A)R and GlyR agonists. We then discuss the proposed non-synaptic release mechanisms and/or pathways for GABA, glycine, and taurine. Finally, we summarize recent data about the various roles of non-synaptic GABAergic and glycinergic systems during the development of neuronal networks and in the adult.
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Affiliation(s)
- Herve Le-Corronc
- Institut National de la Santé et de la Recherche Médicale, U952, Centre National de la Recherche Scientifique, UMR 7224, Université Pierre et Marie Curie, 9 quai Saint Bernard, Paris, Ile de France, France
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Oland LA, Gibson NJ, Tolbert LP. Localization of a GABA transporter to glial cells in the developing and adult olfactory pathway of the moth Manduca sexta. J Comp Neurol 2010; 518:815-38. [PMID: 20058309 DOI: 10.1002/cne.22244] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Glial cells have several critical roles in the developing and adult olfactory (antennal) lobe of the moth Manduca sexta. Early in development, glial cells occupy discrete regions of the developing olfactory pathway and processes of gamma-aminobutyric acid (GABA)ergic neurons extend into some of these regions. Because GABA is known to have developmental effects in a variety of systems, we explored the possibility that the glial cells express a GABA transporter that could regulate GABA levels to which olfactory neurons and glial cells are exposed. By using an antibody raised against a characterized high-affinity M. sexta GABA transporter with high sequence homology to known mammalian GABA transporters (Mbungu et al. [1995] Arch. Biochem. Biophys. 318:489-497; Umesh and Gill [2002] J. Comp. Neurol. 448:388-398), we found that the GABA transporter is localized to subsets of centrally derived glial cells during metamorphic adult development. The transporter persists into adulthood in a subset of the neuropil-associated glial cells, but its distribution pattern as determined by light-and electron-microscopic-level immunocytochemistry indicates that it could not serve to regulate GABA concentration in the synaptic cleft. Instead, its role is more likely to regulate extracellular GABA levels within the glomerular neuropil. Expression in the sorting zone glial cells disappears after the period of olfactory receptor axon ingrowth, but may be important during ingrowth if GABA regulates axon growth. Glial cells take up GABA, and that uptake can be blocked by L-2,4-diaminobutyric acid (DABA). This is the first molecular evidence that the central glial cell population in this pathway is heterogeneous.
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Affiliation(s)
- Lynne A Oland
- Department of Neuroscience, University of Arizona, Tucson, Arizona 85721, USA.
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Neuronal and non-neuronal GABA transporters as targets for antiepileptic drugs. Pharmacol Ther 2010; 125:394-401. [DOI: 10.1016/j.pharmthera.2009.11.007] [Citation(s) in RCA: 133] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 11/24/2009] [Indexed: 12/23/2022]
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Developmental localization of potassium chloride co-transporter 2 (KCC2), GABA and vesicular GABA transporter (VGAT) in the postnatal mouse somatosensory cortex. Neurosci Res 2010; 67:137-48. [PMID: 20219572 DOI: 10.1016/j.neures.2010.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2009] [Revised: 02/17/2010] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
Abstract
Gamma-amino butyric acid (GABA) mediates the hyperpolarization of membrane potential, negatively regulating glutamatergic activity in the adult brain, whereas, mediates depolarization in the immature brain. This developmental shift in GABA actions is induced by the expression of potassium chloride co-transporter 2 (KCC2). In this study, we focused on the developing mouse somatosensory cortex, where the barrel structure in layer 4 is altered by the whisker-lesion during the critical period, before postnatal day 4 (P4). First, to clarify the time-course of postnatal changes in GABA actions, we investigated the developmental localization of KCC2. Second, to reveal its spatial and temporal relationship with GABA synapse formation, we examined the developmental localization of GABA and vesicular GABA transporter. KCC2 was localized within the pyramidal cells in layer 5 after P3, granule cells in layer 4 after P5 and neurons in layers 2 and 3 after P7, indicating that KCC2 was expressed in the chronological order of neuronal settling at the destination. The onset of KCC2 localization was almost concomitant with the formation of GABA synapses, suggesting that GABA was inhibitory after GABA synapse formation. Furthermore, extrasynaptically released GABA might be involved in the maintenance of activity-dependent plasticity as an excitatory transmitter during the critical period.
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Barbaresi P. Postnatal development of GABA-immunoreactive neurons and terminals in rat periaqueductal gray matter: A light and electron microscopic study. J Comp Neurol 2010; 518:2240-60. [DOI: 10.1002/cne.22329] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Bullock WM, Bolognani F, Botta P, Valenzuela CF, Perrone-Bizzozero NI. Schizophrenia-like GABAergic gene expression deficits in cerebellar Golgi cells from rats chronically exposed to low-dose phencyclidine. Neurochem Int 2009; 55:775-82. [PMID: 19651169 DOI: 10.1016/j.neuint.2009.07.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 07/22/2009] [Accepted: 07/27/2009] [Indexed: 12/21/2022]
Abstract
One of the most consistent findings in schizophrenia is the decreased expression of the GABA synthesizing enzymes GAD(67) and GAD(65) in specific interneuron populations. This dysfunction is observed in distributed brain regions including the prefrontal cortex, hippocampus, and cerebellum. In an effort to understand the mechanisms for this GABA deficit, we investigated the effect of the N-methyl-D-aspartate receptor (NMDAR) antagonist phencyclidine (PCP), which elicits schizophrenia-like symptoms in both humans and animal models, in a chronic, low-dose exposure paradigm. Adult rats were given PCP at a dose of 2.58 mg/kg/day i.p. for a month, after which levels of various GABAergic cell mRNAs and other neuromodulators were examined in the cerebellum by qRT-PCR. Administration of PCP decreased the expression of GAD(67), GAD(65), and the presynaptic GABA transporter GAT-1, and increased GABA(A) receptor subunits similar to those seen in patients with schizophrenia. Additionally, we found that the mRNA levels of two Golgi cell selective NMDAR subunits, NR2B and NR2D, were decreased in PCP-treated rats. Furthermore, we localized the deficits in GAD(67) expression solely to these interneurons. Slice electrophysiological studies showed that spontaneous firing of Golgi cells was reduced by acute exposure to low-dose PCP, suggesting that these neurons are particularly vulnerable to NMDA receptor antagonism. In conclusion, our results demonstrate that chronic exposure to low levels of PCP in rats mimics the GABAergic alterations reported in the cerebellum of patients with schizophrenia (Bullock et al., 2008. Am. J. Psychiatry 165, 1594-1603), further supporting the validity of this animal model.
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Affiliation(s)
- W Michael Bullock
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
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Viltono L, Patrizi A, Fritschy JM, Sassoè-Pognetto M. Synaptogenesis in the cerebellar cortex: differential regulation of gephyrin and GABAA receptors at somatic and dendritic synapses of Purkinje cells. J Comp Neurol 2008; 508:579-91. [PMID: 18366064 DOI: 10.1002/cne.21713] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In rodent cerebellar cortex, synaptogenesis occurs entirely postnatally, allowing study of the mechanisms of synapse formation in vivo. Here we monitored the clustering of GABA(A) receptors and the scaffolding protein gephyrin at GABAergic postsynaptic sites during rat cerebellar development. We found that GABA(A) receptors and gephyrin co-aggregate at nascent synapses in the molecular and Purkinje cell layers with a similar time course. With few exceptions, gephyrin and GABA(A) receptor subunits clustered selectively in front of presynaptic boutons expressing the vesicular inhibitory amino acid transporter VIAAT and no ectopic localization of these molecules was observed. Surprisingly, gephyrin clusters outlining the cell body of Purkinje cells were transient, and disappeared rapidly at the end of the second postnatal week. The loss of gephyrin from perisomatic synapses was coincident with a significant reduction in the size of GABA(A) receptor clusters. Furthermore, these changes were accompanied by a developmental decrease in the size of synaptic appositions, as documented by electron microscopy. These findings suggest that gephyrin takes part in the initial assembly of postsynaptic specializations and reveal an unsuspected heterogeneity in the molecular organization of the postsynaptic apparatus at somatic and dendritic synapses of mature Purkinje cells.
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Affiliation(s)
- Laura Viltono
- Department of Anatomy, Pharmacology and Forensic Medicine, University of Turin, I-10126 Torino, Italy
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Enhancement of GABA release through endogenous activation of axonal GABA(A) receptors in juvenile cerebellum. J Neurosci 2007; 27:12452-63. [PMID: 18003823 DOI: 10.1523/jneurosci.3413-07.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Recent evidence indicates the presence of presynaptic GABA(A) receptors (GABA(A)Rs) in the axon domain of several classes of central neurons, including cerebellar basket and stellate cells. Here, we investigate the possibility that these receptors could be activated in the absence of electrical or chemical stimulation. We find that low concentrations of GABA increase the frequency of miniature GABAergic synaptic currents. Submaximal concentrations of a GABA(A)R blocker, gabazine, decrease both the miniature current frequency and the probability of evoked GABA release. Zolpidem, an agonist of the benzodiazepine binding site, and NO-711 (1-[2-[[(diphenylmethylene)imino]oxy]ethyl]-1,2,5,6-tetrahydro-3-pyridinecarboxylic acid hydrochloride), a blocker of GABA uptake, both increase the frequency of miniature currents. These effects occur up to postnatal day 14, but not later. Immunohistochemistry indicates the presence of alpha1-containing GABA(A)Rs in interneuron presynaptic terminals with a similar age dependence. We conclude that, under resting conditions, axonal GABA(A)Rs are significantly activated, that this activation results in enhanced GABA release, and that it can be augmented by increasing the affinity of GABA(A)Rs or reducing GABA uptake. Our findings suggest the existence of a positive-feedback mechanism involving presynaptic GABA(A)Rs that maintains a high release rate and a high local GABA concentration in the immature cerebellar network.
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Astori S, Köhr G. Sustained granule cell activity disinhibits juvenile mouse cerebellar stellate cells through presynaptic mechanisms. J Physiol 2007; 586:575-92. [PMID: 18033809 DOI: 10.1113/jphysiol.2007.146522] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
GABA release from cerebellar molecular layer interneurons can be modulated by presynaptic glutamate and/or GABA B receptors upon perfusing the respective agonists. However, it is unclear how release and potential spillover of endogenous transmitter lead to activation of presynaptic receptors. High frequency firing of granule cells, as observed in vivo upon sensory stimulation, could lead to glutamate and/or GABA spillover. Here, we established sustained glutamatergic activity in the granule cell layer of acute mouse cerebellar slices and performed 190 paired recordings from connected stellate cells. Train stimulation at 50 Hz reduced by about 30% the peak amplitude of IPSCs evoked by brief depolarization of the presynaptic cell in 2-week-old mice. A presynaptic mechanism was indicated by changes in failure rate, paired-pulse ratio and coefficient of variation of evoked IPSCs. Furthermore, two-photon Ca2+ imaging in identified Ca2+ hot spots of stellate cell axons confirmed reduced presynaptic Ca2+ influx after train stimulation within the granular layer. Pharmacological experiments indicated that glutamate released from parallel fibres activated AMPARs in stellate cells, evoking GABA release from surrounding cells. Consequential GABA spillover activated presynaptic GABA B Rs, which reduced the amplitude of eIPSCs. Two-thirds of the total disinhibitory effect were mediated by GABA B Rs, one-third being attributable to presynaptic AMPARs. This estimation was confirmed by the observation that bath applied baclofen induced a more pronounced reduction of evoked IPSCs than kainate. Granule cell-mediated disinhibition persisted at near-physiological temperature but was strongly diminished in 3-week-old mice. At this age, GABA release probability was not reduced and presynaptic GABA B Rs were still detectable, but GABA uptake appeared to be advanced, attenuating GABA spillover. Thus, sustained granule cell activity modulates stellate cell-to-stellate cell synapses, involving transmitter spillover during a developmentally restricted period.
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Affiliation(s)
- Simone Astori
- Department of Molecular Neurobiology, Max-Planck-Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
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Migani P, Bartlett C, Dunlop S, Beazley L, Rodger J. Ephrin-B2 immunoreactivity distribution in adult mouse brain. Brain Res 2007; 1182:60-72. [DOI: 10.1016/j.brainres.2007.08.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 08/29/2007] [Accepted: 08/29/2007] [Indexed: 12/30/2022]
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Simat M, Ambrosetti L, Lardi-Studler B, Fritschy JM. GABAergic synaptogenesis marks the onset of differentiation of basket and stellate cells in mouse cerebellum. Eur J Neurosci 2007; 26:2239-56. [PMID: 17892480 DOI: 10.1111/j.1460-9568.2007.05846.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Type 2 glycine transporter (GlyT2) mediates intracellular glycine transport and is expressed selectively in glycinergic neurons. Expression of GlyT2 gene promoter-driven enhanced green fluorescent protein (eGFP) in BAC transgenic mice allows selective visualization of glycinergic neurons by fluorescence microscopy. Here, we show that cerebellar interneuron precursors identified by the transcription factor Pax2, including gamma-aminobutyric acid (GABA)ergic interneurons of the molecular layer (ML; basket and stellate cells), transiently express GlyT2-eGFP during development. In contrast, expression of endogenous GlyT2 is restricted to glycinergic Golgi cells. Comparison with knock-in mice expressing eGFP in GABAergic neurons [glutamic acid decarboxylase (GAD)67-eGFP] revealed that GlyT2-eGFP expression often precedes GAD67-eGFP and is therefore a marker of immature GABAergic interneurons. In the internal granule cell layer, GABAergic Golgi cells differentiated shortly after birth, prior to glycinergic Golgi cells. In the ML, GlyT2-eGFP-positive precursor cells migrated until the boundary with the external granule cell layer, forming an inside-out maturation gradient that determined the final position of interneurons in the ML. After migration, GlyT2-eGFP gradually disappeared, while interneurons differentiated morphologically and became immunoreactive for parvalbumin, the GABA(A) receptor alpha1 subunit, and the K(+)Cl(-) exchanger KCC2 (K(+)Cl(-) cotransporter type 2). Numerous presumptive GABAergic synaptic terminals were seen on immature ML interneurons as early as P4, preceding the expression of these neurochemical markers. These results suggest that GABAergic synaptogenesis marks the onset of differentiation of basket and stellate cells in the mouse cerebellum, and that GABAergic synaptic function might contribute to the differentiation of interneurons in the cerebellar cortex.
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Affiliation(s)
- Marija Simat
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland
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Fehr C, Hohmann N, Gründer G, Dielentheis TF, Buchholz HG, Chechko N, Yakushev I, Landvogt C, Bartenstein P, Urban R, Schreckenberger M. Tiagabine does not attenuate alcohol-induced activation of the human reward system. Psychopharmacology (Berl) 2007; 191:975-83. [PMID: 17265078 DOI: 10.1007/s00213-006-0696-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Accepted: 12/26/2006] [Indexed: 10/23/2022]
Abstract
RATIONALE The rewarding effects of ethanol and other drugs of abuse are mediated by activation of the mesolimbic dopamine system. Recent neuroimaging studies in primates and humans suggest that cocaine-induced dopamine stimulation might be diminished by drugs augmenting gamma-aminobutyric acid A (GABA-A) receptor function such as the GABA transaminase inhibitor vigabatrin. OBJECTIVES The objective of this study was to test the property of the selective GABA transporter 1 (GAT1) inhibitor tiagabine to block ethanol-induced activation of the mesolimbic reward system in an i.v. ethanol challenge. MATERIALS AND METHODS Twenty nonaddicted healthy volunteers underwent an i.v. ethanol challenge after 1 week of tiagabine (15 mg/day) administration. Neuronal activation was measured using [(18)F]-fluoro-deoxyglucose positron emission tomography (PET). RESULTS Tiagabine did not prevent ethanol-induced stimulation of the mesolimbic reward system but augmented ethanol-induced hypometabolism within areas of the visual system and the cerebellum. Tiagabine alone also decreased neuronal metabolism within parts of the right temporal cortex that are highly enriched with GABA-ergic neurons. CONCLUSIONS Our ethanol challenge imaging study does not provide supporting evidence that the GAT1 inhibitor tiagabine diminishes the rewarding effects of ethanol. Further PET imaging studies using established anticraving compounds, such as the mu-opioid receptor antagonist naltrexone and antiepileptic drugs affecting the GABA-ergic system more broadly, will provide additional important insights on the interaction between the GABA-ergic and the brain reward system in vivo and the suitability of GABA-ergic drugs as anticraving compounds.
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Affiliation(s)
- Christoph Fehr
- Department of Psychiatry, University of Mainz, Untere Zahlbacher Strasse 8, 55131, Mainz, Germany.
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Sotelo C. Development of “Pinceaux” formations and dendritic translocation of climbing fibers during the acquisition of the balance between glutamatergic and γ-aminobutyric acidergic inputs in developing Purkinje cells. J Comp Neurol 2007; 506:240-62. [DOI: 10.1002/cne.21501] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Takayama C, Inoue Y. Developmental localization of potassium chloride co-transporter 2 in granule cells of the early postnatal mouse cerebellum with special reference to the synapse formation. Neuroscience 2006; 143:757-67. [PMID: 17008020 DOI: 10.1016/j.neuroscience.2006.08.044] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2006] [Revised: 07/26/2006] [Accepted: 08/17/2006] [Indexed: 11/16/2022]
Abstract
In the adult CNS, GABA is the predominant inhibitory neurotransmitter, mediating the hyperpolarization of membrane potential and regulating the glutamatergic activity. In the immature CNS, on the other hand, GABA mediates depolarization and is involved in controlling morphogenesis. This developmental shift in GABA actions from depolarization to hyperpolarization occurs as a result of decreasing the intracellular chloride ion (Cl(-)) concentration ([Cl(-)](i)) which is regulated by the potassium (K(+))-Cl(-) co-transporter 2 (KCC2). To clarify the time-course of changes in the GABA actions during development, we examined the developmental localization of the KCC2 in the granule cells of the postnatal mouse cerebellum using specific antibodies against KCC2. The granule cell precursors and migrating granule cells were devoid of immunoreactivity against KCC2 antibodies. At postnatal day 3 (P3), the KCC2-immunolabeling was negative in the internal granular layer, although synaptophysin-positive mossy fiber terminals were detected. At P5, we first detected the KCC2-immunolabeling at the somata of granule cells and their dendrites before granule cells received inhibitory input from Golgi cells. Almost all KCC2-positive dendrites (more than 98%) attached to and formed synapses with mossy fiber terminals. As development proceeded, the number of KCC2-positive granule cells increased, and all granule cells became positive by P21. These results suggested that GABAergic transmission on granule cells might shift from excitation to inhibition after the synapse formation, and the excitatory synapse-formation and related factors might be the triggers for the expression and localization of the KCC2 in the granule cells. Furthermore, it was also suggested that formation of the GABAergic synapses and GABAergic transmission were not necessary for the KCC2-expression in the mouse cerebellar granule cells in vivo.
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Affiliation(s)
- C Takayama
- Department of Molecular Neuroanatomy, Hokkaido University School of Medicine, Kita-15 Nishi-7, Kita-Ku, Sapporo 060-8638, Japan.
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Fritschy JM, Panzanelli P, Kralic JE, Vogt KE, Sassoè-Pognetto M. Differential dependence of axo-dendritic and axo-somatic GABAergic synapses on GABAA receptors containing the alpha1 subunit in Purkinje cells. J Neurosci 2006; 26:3245-55. [PMID: 16554475 PMCID: PMC6674111 DOI: 10.1523/jneurosci.5118-05.2006] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Synapse formation and maintenance require extensive transsynaptic interactions involving multiple signal transduction pathways. In the cerebellum, Purkinje cells (PCs) receive GABAergic, axo-dendritic synapses from stellate cells and axo-somatic synapses from basket cells, both with GABAA receptors containing the alpha1 subunit. Here, we investigated the effects of a targeted deletion of the alpha1 subunit gene on GABAergic synaptogenesis in PCs, using electrophysiology and immunoelectron microscopy. Whole-cell patch-clamp recordings in acute slices revealed that PCs from alpha1(0/0) mice lack spontaneous and evoked IPSCs, demonstrating that assembly of functional GABAA receptors requires the alpha1 subunit. Ultrastructurally, stellate cell synapses on PC dendrites were reduced by 75%, whereas basket cell synapses on the soma were not affected, despite the lack of GABAA-mediated synaptic transmission. Most strikingly, GABAergic terminals were retained in the molecular layer of adult alpha1(0/0) mice and formed heterologous synapses with PC spines characterized by a well differentiated asymmetric postsynaptic density. These synapses lacked presynaptic glutamatergic markers and postsynaptic AMPA-type glutamate receptors but contained delta2-glutamate receptors. During postnatal development, initial steps of GABAergic synapse formation were qualitatively normal, and heterologous synapses appeared in parallel with maturation of dendritic spines. These results suggest that synapse formation in the cerebellum is governed by neurotransmitter-independent mechanisms. However, in the absence of GABAA-mediated transmission, GABAergic terminals in the molecular layer apparently become responsive to synaptogenic signals from PC spines and form stable heterologous synapses. In contrast, maintenance of axo-somatic GABAergic synapses does not depend on functional GABAA receptors, suggesting differential regulation in distinct subcellular compartments.
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Affiliation(s)
- Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, CH-8057 Zurich, Switzerland.
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Abstract
In the adult central nervous system (CNS), gamma-amino butyric acid (GABA) is a predominant inhibitory neurotransmitter, and is involved in the expression of various higher brain functions. In the cerebellum, formation of GABAergic synapses is crucial for cerebellar functions. However, it is not fully understood how GABAergic synapses and networks are formed. We are morphologically investigating the developmental changes in GABAergic signaling and the mechanisms underlying the assembly of GABAergic synapses using the cerebellum, which provides an ideal system for the investigation of brain development. The anatomy and development of GABAergic synapses and networks in the cerebellar cortex are reviewed, the key factors for the formation of GABAergic synapses are addressed, and the mechanisms underlying the formation of cerebellar GABAergic networks are discussed.
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Affiliation(s)
- Chitoshi Takayama
- Department of Molecular Neuroanatomy, Hokkaido University School of Medicine, Sapporo, Japan.
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Takayama C. GABAergic signaling in the developing cerebellum. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2005; 71:63-94. [PMID: 16512346 DOI: 10.1016/s0074-7742(05)71003-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Chitoshi Takayama
- Department of Molecular Neuroanatomy, Hokkaido University School of Medicine, Sapporo, Japan
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