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Massri AJ, Fitzpatrick M, Cunny H, Li JL, Harry GJ. Differential gene expression profiling implicates altered network development in rat postnatal day 4 cortex following 4-Methylimidazole (4-MeI) induced maternal seizures. Neurotoxicol Teratol 2023; 100:107301. [PMID: 37783441 PMCID: PMC10843020 DOI: 10.1016/j.ntt.2023.107301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/31/2023] [Accepted: 09/19/2023] [Indexed: 10/04/2023]
Abstract
Compromised maternal health leading to maternal seizures can have adverse effects on the healthy development of offspring. This may be the result of inflammation, hypoxia-ischemia, and altered GABA signaling. The current study examined cortical tissue from F2b (2nd litter of the 2nd generation) postnatal day 4 (PND4) offspring of female Harlan SD rats chronically exposed to the seizuregenic compound, 4-Methylimidazole (0, 750, or 2500 ppm 4-MeI). Maternal seizures were evident only at 2500 ppm 4-MeI. GABA related gene expression as examined by qRT-PCR and whole genome microarray showed no indication of disrupted GABA or glutamatergic signaling. Canonical pathway hierarchical clustering and multi-omics combinatory genomic (CNet) plots of differentially expressed genes (DEG) showed alterations in genes associated with regulatory processes of cell development including neuronal differentiation and synaptogenesis. Functional enrichment analysis showed a similarity of cellular processes across the two exposure groups however, the genes comprising each cluster were primarily unique rather than shared and often showed different directionality. A dose-related induction of cytokine signaling was indicated however, pathways associated with individual cytokine signaling were not elevated, suggesting an alternative involvement of cytokine signaling. Pathways related to growth process and cell signaling showed a negative activation supporting an interpretation of disruption or delay in developmental processes at the 2500 ppm 4-MeI exposure level with maternal seizures. Thus, while GABA signaling was not altered as has been observed with maternal seizures, the pattern of DEG suggested a potential for alteration in neuronal network formation.
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Affiliation(s)
- Abdull J Massri
- Integrative Bioinformatics, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mackenzie Fitzpatrick
- Mechanistic Toxicology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Helen Cunny
- Office of the Scientific Director, Division of Translational Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jian-Liang Li
- Integrative Bioinformatics, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - G Jean Harry
- Mechanistic Toxicology Branch, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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Michalettos G, Ruscher K. Crosstalk Between GABAergic Neurotransmission and Inflammatory Cascades in the Post-ischemic Brain: Relevance for Stroke Recovery. Front Cell Neurosci 2022; 16:807911. [PMID: 35401118 PMCID: PMC8983863 DOI: 10.3389/fncel.2022.807911] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/28/2022] [Indexed: 11/28/2022] Open
Abstract
Adaptive plasticity processes are required involving neurons as well as non-neuronal cells to recover lost brain functions after an ischemic stroke. Recent studies show that gamma-Aminobutyric acid (GABA) has profound effects on glial and immune cell functions in addition to its inhibitory actions on neuronal circuits in the post-ischemic brain. Here, we provide an overview of how GABAergic neurotransmission changes during the first weeks after stroke and how GABA affects functions of astroglial and microglial cells as well as peripheral immune cell populations accumulating in the ischemic territory and brain regions remote to the lesion. Moreover, we will summarize recent studies providing data on the immunomodulatory actions of GABA of relevance for stroke recovery. Interestingly, the activation of GABA receptors on immune cells exerts a downregulation of detrimental anti-inflammatory cascades. Conversely, we will discuss studies addressing how specific inflammatory cascades affect GABAergic neurotransmission on the level of GABA receptor composition, GABA synthesis, and release. In particular, the chemokines CXCR4 and CX3CR1 pathways have been demonstrated to modulate receptor composition and synthesis. Together, the actual view on the interactions between GABAergic neurotransmission and inflammatory cascades points towards a specific crosstalk in the post-ischemic brain. Similar to what has been shown in experimental models, specific therapeutic modulation of GABAergic neurotransmission and inflammatory pathways may synergistically promote neuronal plasticity to enhance stroke recovery.
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Affiliation(s)
- Georgios Michalettos
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
| | - Karsten Ruscher
- Laboratory for Experimental Brain Research, Division of Neurosurgery, Department of Clinical Sciences, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
- LUBIN Lab—Lunds Laboratorium för Neurokirurgisk Hjärnskadeforskning, Division of Neurosurgery, Department of Clinical Sciences, Lund University, Lund, Sweden
- *Correspondence: Karsten Ruscher
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Abstract
In mammals, the selective transformation of transient experience into stored memory occurs in the hippocampus, which develops representations of specific events in the context in which they occur. In this review, we focus on the development of hippocampal circuits and the self-organized dynamics embedded within them since the latter critically support the role of the hippocampus in learning and memory. We first discuss evidence that adult hippocampal cells and circuits are sculpted by development as early as during embryonic neurogenesis. We argue that these primary developmental programs provide a scaffold onto which later experience of the external world can be grafted. Next, we review the different sequences in the development of hippocampal cells and circuits at anatomical and functional levels. We cover a period extending from neurogenesis and migration to the appearance of phenotypic diversity within hippocampal cells, and their wiring into functional networks. We describe the progressive emergence of network dynamics in the hippocampus, from sensorimotor-driven early sharp waves to sequences of place cells tracking relational information. We outline the critical turn points and discontinuities in that developmental journey, and close by formulating open questions. We propose that rewinding the process of hippocampal development helps understand the main organization principles of memory circuits.
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Affiliation(s)
- Rosa Cossart
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France
| | - Rustem Khazipov
- Inserm, INMED, Turing Center for Living Systems, Aix Marseille University, Marseille, France.,Laboratory of Neurobiology, Kazan Federal University, Kazan Russia
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Fish KN, Rocco BR, DeDionisio AM, Dienel SJ, Sweet RA, Lewis DA. Altered Parvalbumin Basket Cell Terminals in the Cortical Visuospatial Working Memory Network in Schizophrenia. Biol Psychiatry 2021; 90:47-57. [PMID: 33892915 PMCID: PMC8243491 DOI: 10.1016/j.biopsych.2021.02.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 01/21/2021] [Accepted: 02/11/2021] [Indexed: 12/28/2022]
Abstract
BACKGROUND Visuospatial working memory (vsWM), which is commonly impaired in schizophrenia, involves information processing across the primary visual cortex, association visual cortex, posterior parietal cortex, and dorsolateral prefrontal cortex (DLPFC). Within these regions, vsWM requires inhibition from parvalbumin-expressing basket cells (PVBCs). Here, we analyzed indices of PVBC axon terminals across regions of the vsWM network in schizophrenia. METHODS For 20 matched pairs of subjects with schizophrenia and unaffected comparison subjects, tissue sections from the primary visual cortex, association visual cortex, posterior parietal cortex, and DLPFC were immunolabeled for PV, the 65- and 67-kDa isoforms of glutamic acid decarboxylase (GAD65 and GAD67) that synthesize GABA (gamma-aminobutyric acid), and the vesicular GABA transporter. The density of PVBC terminals and of protein levels per terminal was quantified in layer 3 of each cortical region using fluorescence confocal microscopy. RESULTS In comparison subjects, all measures, except for GAD65 levels, exhibited a caudal-to-rostral decline across the vsWM network. In subjects with schizophrenia, the density of detectable PVBC terminals was significantly lower in all regions except the DLPFC, whereas PVBC terminal levels of PV, GAD67, and GAD65 proteins were lower in all regions. A composite measure of inhibitory strength was lower in subjects with schizophrenia, although the magnitude of the diagnosis effect was greater in the primary visual, association visual, and posterior parietal cortices than in the DLPFC. CONCLUSIONS In schizophrenia, alterations in PVBC terminals across the vsWM network suggest the presence of a shared substrate for cortical dysfunction during vsWM tasks. However, regional differences in the magnitude of the disease effect on an index of PVBC inhibitory strength suggest region-specific alterations in information processing during vsWM tasks.
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Affiliation(s)
- Kenneth N Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania.
| | - Brad R Rocco
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Adam M DeDionisio
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Samuel J Dienel
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Robert A Sweet
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - David A Lewis
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania; Department of Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania
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Abstract
The adult brain is the result of a multistages complex neurodevelopmental process involving genetic, molecular and microenvironmental factors as well as diverse patterns of electrical activity. In the postnatal life, immature neuronal circuits undergo an experience-dependent maturation during critical periods of plasticity, but the brain still retains plasticity during adult life. In all these stages, the neurotransmitter GABA plays a pivotal role. In this chapter, we will describe the interaction of 5-HT with GABA in regulating neurodevelopment and plasticity.
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Neonatal proinflammatory challenge evokes a microglial response and affects the ratio between subtypes of GABAergic interneurons in the hippocampus of juvenile rats: sex-dependent and sex-independent effects. Brain Struct Funct 2021; 226:563-574. [DOI: 10.1007/s00429-020-02199-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 12/16/2020] [Indexed: 10/22/2022]
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Zou RX, Gu X, Ding JJ, Wang T, Bi N, Niu K, Ge M, Chen XT, Wang HL. Pb exposure induces an imbalance of excitatory and inhibitory synaptic transmission in cultured rat hippocampal neurons. Toxicol In Vitro 2019; 63:104742. [PMID: 31785328 DOI: 10.1016/j.tiv.2019.104742] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 11/12/2019] [Accepted: 11/24/2019] [Indexed: 12/16/2022]
Abstract
An appropriate balance of excitatory and inhibitory synapse maintains the network stability of the central nervous system. Our recent work showed lead (Pb) exposure can inhibit synaptic transmission in cultured hippocampal neurons. However, it is not clear whether Pb exposure disrupt the balance of excitatory and inhibitory synaptic transmission. Here, primary cultured hippocampal neurons from Sprague-Dawley (SD) rats were exposed to Pb (0.2 μM, 1 μM, 5 μM, respectively) from Days in Vitro (DIV) 7 to DIV 12 for 5 days and the excitatory and inhibitory synaptic transmission was examined. Patch clamp recording results showed that distinct from exposures of 0.2 μM and 5 μM, 1 μM Pb exposure significantly increased the mIPSC frequency and decreased the mEPSC frequency, leading to a uniform inhibitory outcome. Further, the number of inhibitory presynaptic puncta was significantly increased after 1 μM Pb exposure, while the number of excitatory presynaptic terminals was decreased. In addition 1 μM Pb increased the glutamic acid decarboxylase (GAD65) expression and the surface GABAA receptor (GABAAR) clusters. This shift might potentiate the synthesis of GABA and enhance the surface distribution of postsynaptic GABAAR clusters in hippocampus neurons. Together, these data showed that Pb exposure disrupted the balance of excitatory and inhibitory synaptic transmission via abnormal GABAergic neurotransmission.
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Affiliation(s)
- Rong-Xin Zou
- Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui 230009, PR China; School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Xiaozhen Gu
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Jin-Jun Ding
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Tiandong Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Nanxi Bi
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Kang Niu
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Mengmeng Ge
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Xiang-Tao Chen
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230031, PR China.
| | - Hui-Li Wang
- Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, 193 Tunxi Road, Hefei, Anhui 230009, PR China; School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China.
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Katahira T, Miyazaki N, Motoyama J. Immediate effects of maternal separation on the development of interneurons derived from medial ganglionic eminence in the neonatal mouse hippocampus. Dev Growth Differ 2018; 60:278-290. [DOI: 10.1111/dgd.12540] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 04/25/2018] [Accepted: 04/25/2018] [Indexed: 01/21/2023]
Affiliation(s)
- Tatsuya Katahira
- Organization of Advanced Research and Education; Doshisha University; Kyoto Japan
| | | | - Jun Motoyama
- Laboratory of Developmental Neurobiology; Graduate School of Brain Science; Doshisha University; Kyoto Japan
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Acker DWM, Wong I, Kang M, Paradis S. Semaphorin 4D promotes inhibitory synapse formation and suppresses seizures in vivo. Epilepsia 2018; 59:1257-1268. [PMID: 29799628 DOI: 10.1111/epi.14429] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVE We previously discovered a role for the extracellular domain of the transmembrane protein semaphorin 4D (Sema4D) as a fast-acting, selective, and positive regulator of functional γ-aminobutyric acid (GABA)ergic synapse formation in hippocampal neuronal culture. We also demonstrated that Sema4D treatment increases inhibitory tone and suppresses hyperexcitability in an organotypic hippocampal slice culture model of epilepsy. Here, we investigate the ability of Sema4D to promote GABAergic synapse formation and suppress seizure activity in vivo in adult mice. METHODS We performed a 3-hour, intrahippocampal infusion of Sema4D or control protein into the CA1 region of adult mice. To quantify GABAergic presynaptic bouton density, we performed immunohistochemistry on hippocampal tissue sections isolated from these animals using an antibody that specifically recognizes the glutamic acid decarboxylase isoform 65 protein (GAD65), which is localized to presynaptic GABAergic boutons. To assess seizure activity, we employed 2 in vivo mouse models of epilepsy, intravenous (iv) pentylenetetrazol (PTZ) and hippocampal electrical kindling, in the presence or absence of Sema4D treatment. We monitored seizure activity by behavioral observation or electroencephalography (EEG). To assay the persistence of the Sema4D effect, we monitored seizure activity and measured the density of GAD65-positive presynaptic boutons 3 or 48 hours after Sema4D infusion. RESULTS Sema4D-treated mice displayed an elevated density of GABAergic presynaptic boutons juxtaposed to hippocampal pyramidal neuron cell bodies, consistent with the hypothesis that Sema4D promotes the formation of new inhibitory synapses in vivo. In addition, Sema4D acutely suppressed seizures in both the PTZ and electrical kindling models. When we introduced a 48-hour gap between Sema4D treatment and the seizure stimulus, seizure activity was indistinguishable from controls. Moreover, immunohistochemistry on brain sections or hippocampal slices isolated 3 hours, but not 48 hours, after Sema4D treatment displayed an increase in GABAergic bouton density, demonstrating temporal correlation between the effects of Sema4D on seizures and GABAergic synaptic components. SIGNIFICANCE Our findings suggest a novel approach to treating acute seizures: harnessing synaptogenic molecules to enhance connectivity in the inhibitory network.
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Affiliation(s)
- Daniel W M Acker
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
| | - Irene Wong
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
| | - Mihwa Kang
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
| | - Suzanne Paradis
- Department of Biology, National Center for Behavioral Genomics, Brandeis University, Waltham, MA, USA
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10
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Hou H, Fan Q, He W, Suh H, Hu X, Yan R. BACE1 Deficiency Causes Abnormal Neuronal Clustering in the Dentate Gyrus. Stem Cell Reports 2017; 9:217-230. [PMID: 28669600 PMCID: PMC5511112 DOI: 10.1016/j.stemcr.2017.05.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 12/04/2022] Open
Abstract
BACE1 is validated as Alzheimer's β-secretase and a therapeutic target for Alzheimer's disease. In examining BACE1-null mice, we discovered that BACE1 deficiency develops abnormal clusters of immature neurons, forming doublecortin-positive neuroblasts, in the developing dentate gyrus, mainly in the subpial zone (SPZ). Such clusters were rarely observed in wild-type SPZ and not reported in other mouse models. To understand their origins and fates, we examined how neuroblasts in BACE1-null SPZ mature and migrate during early postnatal development. We show that such neuroblasts are destined to form Prox1-positive granule cells in the dentate granule cell layer, and mainly mature to form excitatory neurons, but not inhibitory neurons. Mechanistically, higher levels of reelin potentially contribute to abnormal neurogenesis and timely migration in BACE1-null SPZ. Altogether, we demonstrate that BACE1 is a critical regulator in forming the dentate granule cell layer through timely maturation and migration of SPZ neuroblasts. BACE1 deficiency causes abnormal neuronal clusters retained in the mouse SPZ Mis-migrated neural progenitor cells in the SPZ are destined to form granule cells Such neural progenitor cells form excitatory neurons but not inhibitor neurons Elevated levels of reelin contribute to abnormal neuronal maturation and migration
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Affiliation(s)
- Hailong Hou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Qingyuan Fan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Wanxia He
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Hoonkyo Suh
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Xiangyou Hu
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA
| | - Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue/NC30, Cleveland, OH 44195, USA.
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Kim J, Son Y, Kim J, Lee S, Kang S, Park K, Kim SH, Kim JC, Kim J, Takayama C, Im HI, Yang M, Shin T, Moon C. Developmental and degenerative modulation of GABAergic transmission in the mouse hippocampus. Int J Dev Neurosci 2015; 47:320-32. [PMID: 26394279 DOI: 10.1016/j.ijdevneu.2015.08.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 08/05/2015] [Accepted: 08/21/2015] [Indexed: 11/30/2022] Open
Abstract
γ-Aminobutyric acid (GABA) is the main inhibitory neurotransmitter involved in synaptic plasticity. GABAergic transmission is also implicated in developmental and degenerative processes in the brain. The goal of the present study was to understand the developmental and degenerative regulation of GABAergic transmission in the mouse hippocampus by examining changes in GABA receptor subunit mRNA levels and GABA-related protein expression during postnatal development of the hippocampus and trimethyltin (TMT)-induced neurodegeneration in the juvenile (postnatal day [PD] 24) and adult hippocampus (PD 56). During postnatal development, the mRNA levels of GABA A receptor (GABAAR) subunits, including α1, α4, β1, β2, and δ; GABA B receptor (GABABR) subunit 2; and the expression of GABA-related proteins, including glutamic acid decarboxylase, vesicular GABA transporter (VGAT), and potassium chloride cotransporter 2 increased gradually in the mouse hippocampus. The results of seizure scoring and histopathological findings in the hippocampus revealed a more pronounced response to the same administered TMT dose in juvenile mice, compared with that in adult mice. The mRNA levels of most GABA receptor subunits in the juvenile hippocampus, excluding GABAAR subunit β3, were dynamically altered after TMT treatment. The mRNA levels of GABAAR subunits γ2 and δ decreased significantly in the adult hippocampus following TMT treatment, whereas the level of GABABR subunit 1 mRNA increased significantly. Among the GABA-related proteins, only VGAT decreased significantly in the juvenile and adult mouse hippocampus after TMT treatment. In conclusion, regulation of GABAergic signaling in the mouse hippocampus may be related to maturation of the central nervous system and the degree of neurodegeneration during postnatal development and TMT-induced neurodegeneration in the experimental animals.
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Affiliation(s)
- Jinwook Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Yeonghoon Son
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Juhwan Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea; Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 136-791, South Korea
| | - Sueun Lee
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Sohi Kang
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Kyunghwan Park
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Sung-Ho Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Jong-Choon Kim
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea
| | - Jeongtae Kim
- Department of Molecular Anatomy, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Chitoshi Takayama
- Department of Molecular Anatomy, Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan
| | - Heh-In Im
- Center for Neuroscience, Korea Institute of Science and Technology (KIST), Seoul 136-791, South Korea
| | - Miyoung Yang
- Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, South Korea
| | - Taekyun Shin
- Department of Veterinary Anatomy, College of Veterinary Medicine, Jeju National University, Jeju 690-756, South Korea.
| | - Changjong Moon
- Departments of Veterinary Anatomy and Veterinary Toxicology, College of Veterinary Medicine and Animal Medical Institute, Chonnam National University, Gwangju 500-757, South Korea.
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12
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MeCP2 regulates the timing of critical period plasticity that shapes functional connectivity in primary visual cortex. Proc Natl Acad Sci U S A 2015; 112:E4782-91. [PMID: 26261347 DOI: 10.1073/pnas.1506499112] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Mutations in methyl-CpG-binding protein 2 (MeCP2) cause Rett syndrome, an autism spectrum-associated disorder with a host of neurological and sensory symptoms, but the pathogenic mechanisms remain elusive. Neuronal circuits are shaped by experience during critical periods of heightened plasticity. The maturation of cortical GABA inhibitory circuitry, the parvalbumin(+) (PV(+)) fast-spiking interneurons in particular, is a key component that regulates the initiation and termination of the critical period. Using MeCP2-null mice, we examined experience-dependent development of neural circuits in the primary visual cortex. The functional maturation of parvalbumin interneurons was accelerated upon vision onset, as indicated by elevated GABA synthetic enzymes, vesicular GABA transporter, perineuronal nets, and enhanced GABA transmission among PV interneurons. These changes correlated with a precocious onset and closure of critical period and deficient binocular visual function in mature animals. Reduction of GAD67 expression rescued the precocious opening of the critical period, suggesting its major role in MECP2-mediated regulation of experience-driven circuit development. Our results identify molecular changes in a defined cortical cell type and link aberrant developmental trajectory to functional deficits in a model of neuropsychiatric disorder.
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Besser S, Sicker M, Marx G, Winkler U, Eulenburg V, Hülsmann S, Hirrlinger J. A Transgenic Mouse Line Expressing the Red Fluorescent Protein tdTomato in GABAergic Neurons. PLoS One 2015; 10:e0129934. [PMID: 26076353 PMCID: PMC4468179 DOI: 10.1371/journal.pone.0129934] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 05/13/2015] [Indexed: 12/25/2022] Open
Abstract
GABAergic inhibitory neurons are a large population of neurons in the central nervous system (CNS) of mammals and crucially contribute to the function of the circuitry of the brain. To identify specific cell types and investigate their functions labelling of cell populations by transgenic expression of fluorescent proteins is a powerful approach. While a number of mouse lines expressing the green fluorescent protein (GFP) in different subpopulations of GABAergic cells are available, GFP expressing mouse lines are not suitable for either crossbreeding to other mouse lines expressing GFP in other cell types or for Ca2+-imaging using the superior green Ca2+-indicator dyes. Therefore, we have generated a novel transgenic mouse line expressing the red fluorescent protein tdTomato in GABAergic neurons using a bacterial artificial chromosome based strategy and inserting the tdTomato open reading frame at the start codon within exon 1 of the GAD2 gene encoding glutamic acid decarboxylase 65 (GAD65). TdTomato expression was observed in all expected brain regions; however, the fluorescence intensity was highest in the olfactory bulb and the striatum. Robust expression was also observed in cortical and hippocampal neurons, Purkinje cells in the cerebellum, amacrine cells in the retina as well as in cells migrating along the rostral migratory stream. In cortex, hippocampus, olfactory bulb and brainstem, 80% to 90% of neurons expressing endogenous GAD65 also expressed the fluorescent protein. Moreover, almost all tdTomato-expressing cells coexpressed GAD65, indicating that indeed only GABAergic neurons are labelled by tdTomato expression. This mouse line with its unique spectral properties for labelling GABAergic neurons will therefore be a valuable new tool for research addressing this fascinating cell type.
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Affiliation(s)
- Stefanie Besser
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Marit Sicker
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Grit Marx
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Ulrike Winkler
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
| | - Volker Eulenburg
- Institute for Biochemistry and Molecular Medicine, University of Erlangen, Erlangen, Germany
| | - Swen Hülsmann
- Laboratory for Experimental Neuroanesthesiology, Clinic for Anesthesiology, University Hospital Göttingen, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, University of Leipzig, Leipzig, Germany
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Tsintsadze V, Minlebaev M, Suchkov D, Cunningham MO, Khazipov R. Ontogeny of kainate-induced gamma oscillations in the rat CA3 hippocampus in vitro. Front Cell Neurosci 2015; 9:195. [PMID: 26041996 PMCID: PMC4438719 DOI: 10.3389/fncel.2015.00195] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/05/2015] [Indexed: 11/13/2022] Open
Abstract
GABAergic inhibition, which is instrumental in the generation of hippocampal gamma oscillations, undergoes significant changes during development. However, the development of hippocampal gamma oscillations remains largely unknown. Here, we explored the developmental features of kainate-induced oscillations (KA-Os) in CA3 region of rat hippocampal slices. Up to postnatal day P5, the bath application of kainate failed to evoke any detectable oscillations. KA-Os emerged by the end of the first postnatal week; these were initially weak, slow (20-25 Hz, beta range) and were poorly synchronized with CA3 units and synaptic currents. Local field potential (LFP) power, synchronization of units and frequency of KA-Os increased during the second postnatal week to attain gamma (30-40 Hz) frequency by P15-21. Both beta and gamma KA-Os are characterized by alternating sinks and sources in the pyramidal cell layer, likely generated by summation of the action potential-associated currents and GABAergic synaptic currents, respectively. Blockade of GABA(A) receptors with gabazine completely suppressed KA-Os at all ages indicating that GABAergic mechanisms are instrumental in their generation. Bumetanide, a NKCC1 chloride co-transporter antagonist which renders GABAergic responses inhibitory in the immature hippocampal neurons, failed to induce KA-Os at P2-4 indicating that the absence of KA-Os in neonates is not due to depolarizing actions of GABA. The linear developmental profile, electrographic features and pharmacological properties indicate that CA3 hippocampal beta and gamma KA-Os are fundamentally similar in their generative mechanisms and their delayed onset and developmental changes likely reflect the development of perisomatic GABAergic inhibition.
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Affiliation(s)
- Vera Tsintsadze
- INMED, INSERM U-901 Marseille, France ; Aix-Marseille University Marseille, France
| | - Marat Minlebaev
- INMED, INSERM U-901 Marseille, France ; Aix-Marseille University Marseille, France ; Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Dimitry Suchkov
- Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
| | - Mark O Cunningham
- Institute of Neuroscience, The Medical School, Newcastle University Newcastle upon Tyne, UK
| | - Roustem Khazipov
- INMED, INSERM U-901 Marseille, France ; Aix-Marseille University Marseille, France ; Laboratory of Neurobiology, Kazan Federal University Kazan, Russia
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Wu W, Rahman MN, Guo J, Roy N, Xue L, Cahill CM, Zhang S, Jia Z. Function coupling of otoferlin with GAD65 acts to modulate GABAergic activity. J Mol Cell Biol 2015; 7:168-79. [PMID: 25701657 DOI: 10.1093/jmcb/mjv011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 12/22/2014] [Indexed: 01/03/2023] Open
Abstract
Otoferlin, an integral membrane protein implicated in a late stage of exocytosis, has been reported to play a critical role in hearing although the underlying mechanisms remain elusive. However, its widespread tissue distribution infers a more ubiquitous role in synaptic vesicle trafficking. Glutamate, an excitatory neurotransmitter, is converted to its inhibitory counterpart, γ-aminobutyric acid (GABA), by L-glutamic acid decarboxylase (GAD), which exists in soluble (GAD67) and membrane-bound (GAD65) forms. For the first time, we have revealed a close association between otoferlin and GAD65 in both HEK293 and neuronal cells, including SH-SY5Y neuroblastoma and primary rat hippocampus cells, showing a direct interaction between GAD65 and otoferlin's C2 domains. In primary rat hippocampus cells, otoferlin and GAD65 co-localized in a punctate pattern within the cell body, as well as in the axon along the path of vesicular traffic. Significantly, GABA is virtually abolished in otoferlin-knockdown neuronal cells whereas otoferlin overexpression markedly increases endogenous GABA. GABA attenuation in otoferlin-knockdown primary cells is correlated with diminished L-type calcium current. This previously unknown and close correlation demonstrates that otoferlin, through GAD65, modulates GABAergic activity. The discovery of otoferlin-GAD65 functional coupling provides a new avenue for understanding the molecular mechanism by which otoferlin functions in neurological pathways.
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Affiliation(s)
- Wu Wu
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Mona N Rahman
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Jun Guo
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Natalie Roy
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Lihua Xue
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Catherine M Cahill
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada Present address: Department of Anesthesiology & Perioperative Care, University of California Irvine, Irvine, CA, USA
| | - Shetuan Zhang
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada
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Filippi A, Mueller T, Driever W. vglut2 and gad expression reveal distinct patterns of dual GABAergic versus glutamatergic cotransmitter phenotypes of dopaminergic and noradrenergic neurons in the zebrafish brain. J Comp Neurol 2015; 522:2019-37. [PMID: 24374659 PMCID: PMC4288968 DOI: 10.1002/cne.23524] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 11/27/2013] [Accepted: 11/27/2013] [Indexed: 01/22/2023]
Abstract
Throughout the vertebrate lineage, dopaminergic neurons form important neuromodulatory systems that influence motor behavior, mood, cognition, and physiology. Studies in mammals have established that dopaminergic neurons often use γ-aminobutyric acid (GABA) or glutamatergic cotransmission during development and physiological function. Here, we analyze vglut2, gad1b and gad2 expression in combination with tyrosine hydroxylase immunoreactivity in 4-day-old larval and 30-day-old juvenile zebrafish brains to determine which dopaminergic and noradrenergic groups may use GABA or glutamate as a second transmitter. Our results show that most dopaminergic neurons also express GABAergic markers, including the dopaminergic groups of the olfactory bulb (homologous to mammalian A16) and the subpallium, the hypothalamic groups (A12, A14), the prethalamic zona incerta group (A13), the preoptic groups (A15), and the pretectal group. Thus, the majority of catecholaminergic neurons are gad1b/2-positive and coexpress GABA. A very few gad1/2-negative dopaminergic groups, however, express vglut2 instead and use glutamate as a second transmitter. These glutamatergic dual transmitter phenotypes are the Orthopedia transcription factor–dependent, A11-type dopaminergic neurons of the posterior tuberculum. All together, our results demonstrate that all catecholaminergic groups in zebrafish are either GABAergic or glutamatergic. Thus, cotransmission of dopamine and noradrenaline with either GABA or glutamate appears to be a regular feature of zebrafish catecholaminergic systems. We compare our results with those that have been described for mammalian systems, discuss the phenomenon of transmitter dualism in the context of developmental specification of GABAergic and glutamatergic regions in the brain, and put this phenomenon in an evolutionary perspective. J. Comp. Neurol. 522:2019–2037, 2014.
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Affiliation(s)
- Alida Filippi
- Developmental Biology, Institute of Biology I, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104, Freiburg, Germany
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Lower glutamic acid decarboxylase 65-kDa isoform messenger RNA and protein levels in the prefrontal cortex in schizoaffective disorder but not schizophrenia. Biol Psychiatry 2015; 77:167-76. [PMID: 24993056 PMCID: PMC4247819 DOI: 10.1016/j.biopsych.2014.05.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 05/13/2014] [Accepted: 05/21/2014] [Indexed: 01/27/2023]
Abstract
BACKGROUND Altered gamma-aminobutyric acid (GABA) signaling in the prefrontal cortex (PFC) has been associated with cognitive dysfunction in patients with schizophrenia and schizoaffective disorder. Levels of the GABA-synthesizing enzyme glutamic acid decarboxylase 67-kDa isoform (GAD67) in the PFC have been consistently reported to be lower in patients with these disorders, but the status of the second GABA-synthesizing enzyme, glutamic acid decarboxylase 65-kDa isoform (GAD65), remains unclear. METHODS GAD65 messenger RNA (mRNA) levels were quantified in PFC area 9 by quantitative polymerase chain reaction from 62 subjects with schizophrenia or schizoaffective disorder and 62 matched healthy comparison subjects. In a subset of subject pairs, GAD65 relative protein levels were quantified by confocal immunofluorescence microscopy. RESULTS Mean GAD65 mRNA levels were 13.6% lower in subjects with schizoaffective disorder but did not differ in subjects with schizophrenia relative to their matched healthy comparison subjects. In the subjects with schizoaffective disorder, mean GAD65 protein levels were 19.4% lower and were correlated with GAD65 mRNA levels. Lower GAD65 mRNA and protein levels within subjects with schizoaffective disorder were not attributable to factors commonly comorbid with the diagnosis. CONCLUSIONS In concert with previous studies, these findings suggest that schizoaffective disorder is associated with lower levels of both GAD65 and GAD67 mRNA and protein in the PFC, whereas subjects with schizophrenia have lower mean levels of only GAD67 mRNA and protein. Because cognitive function is generally better preserved in patients with schizoaffective disorder relative to patients with schizophrenia, these findings may support an interpretation that GAD65 downregulation provides a homeostatic response complementary to GAD67 downregulation that serves to reduce inhibition in the face of lower PFC network activity.
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18
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Linsalata AE, Chen X, Winters CA, Reese TS. Electron tomography on γ-aminobutyric acid-ergic synapses reveals a discontinuous postsynaptic network of filaments. J Comp Neurol 2014; 522:921-36. [PMID: 23982982 DOI: 10.1002/cne.23453] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Revised: 08/05/2013] [Accepted: 08/13/2013] [Indexed: 12/16/2022]
Abstract
The regulation of synaptic strength at γ-aminobutyric acid (GABA)-ergic synapses is dependent on the dynamic capture, retention, and modulation of GABA A-type receptors by cytoplasmic proteins at GABAergic postsynaptic sites. How these proteins are oriented and organized in the postsynaptic cytoplasm is not yet established. To better understand these structures and gain further insight into the mechanisms by which they regulate receptor populations at postsynaptic sites, we utilized electron tomography to examine GABAergic synapses in dissociated rat hippocampal cultures. GABAergic synapses were identified and selected for tomography by using a set of criteria derived from the structure of immunogold-labeled GABAergic synapses. Tomography revealed a complex postsynaptic network composed of filaments that extend ∼ 100 nm into the cytoplasm from the postsynaptic membrane. The distribution of these postsynaptic filaments was strikingly similar to that of the immunogold label for gephyrin. Filaments were interconnected through uniform patterns of contact, forming complexes composed of 2-12 filaments each. Complexes did not link to form an integrated, continuous scaffold, suggesting that GABAergic postsynaptic specializations are less rigidly organized than glutamatergic postsynaptic densities.
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Affiliation(s)
- Alexander E Linsalata
- Laboratory of Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, 20892
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19
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Deidda G, Bozarth IF, Cancedda L. Modulation of GABAergic transmission in development and neurodevelopmental disorders: investigating physiology and pathology to gain therapeutic perspectives. Front Cell Neurosci 2014; 8:119. [PMID: 24904277 PMCID: PMC4033255 DOI: 10.3389/fncel.2014.00119] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/14/2014] [Indexed: 01/30/2023] Open
Abstract
During mammalian ontogenesis, the neurotransmitter GABA is a fundamental regulator of neuronal networks. In neuronal development, GABAergic signaling regulates neural proliferation, migration, differentiation, and neuronal-network wiring. In the adult, GABA orchestrates the activity of different neuronal cell-types largely interconnected, by powerfully modulating synaptic activity. GABA exerts these functions by binding to chloride-permeable ionotropic GABAA receptors and metabotropic GABAB receptors. According to its functional importance during development, GABA is implicated in a number of neurodevelopmental disorders such as autism, Fragile X, Rett syndrome, Down syndrome, schizophrenia, Tourette's syndrome and neurofibromatosis. The strength and polarity of GABAergic transmission is continuously modulated during physiological, but also pathological conditions. For GABAergic transmission through GABAA receptors, strength regulation is achieved by different mechanisms such as modulation of GABAA receptors themselves, variation of intracellular chloride concentration, and alteration in GABA metabolism. In the never-ending effort to find possible treatments for GABA-related neurological diseases, of great importance would be modulating GABAergic transmission in a safe and possibly physiological way, without the dangers of either silencing network activity or causing epileptic seizures. In this review, we will discuss the different ways to modulate GABAergic transmission normally at work both during physiological and pathological conditions. Our aim is to highlight new research perspectives for therapeutic treatments that reinstate natural and physiological brain functions in neuro-pathological conditions.
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Affiliation(s)
- Gabriele Deidda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
| | - Ignacio F Bozarth
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia Genova, Italy
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Bitzenhofer SH, Hanganu-Opatz IL. Oscillatory coupling within neonatal prefrontal-hippocampal networks is independent of selective removal of GABAergic neurons in the hippocampus. Neuropharmacology 2013; 77:57-67. [PMID: 24056266 DOI: 10.1016/j.neuropharm.2013.09.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 08/13/2013] [Accepted: 09/04/2013] [Indexed: 11/19/2022]
Abstract
GABAergic neurons have been proposed to control oscillatory entrainment and cognitive processing in prefrontal-hippocampal networks. Co-activation of these networks emerges already during neonatal development, with hippocampal theta bursts driving prefrontal oscillations via axonal projections. The cellular substrate of neonatal prefrontal-hippocampal communication and in particular, the role of GABAergic neurons, is still unknown. Here, we used saporin-conjugated anti-vesicular GABA transporter antibodies to cause selective immunotoxic lesion of GABAergic neurons in the CA1 area of the hippocampus during the first postnatal week. Without affecting the somatic development of rat pups, the lesion impaired the generation of hippocampal sharp waves, but not of theta bursts during neonatal development. Moreover, the oscillatory entrainment and firing of neonatal prefrontal cortex as well as the early prefrontal-hippocampal synchrony were largely independent of GABAergic neurotransmission in the hippocampus. Thus, hippocampal interneurons are critical elements for the ontogeny of hippocampal sharp waves, but seem to not control the directed oscillatory coupling between the neonatal prefrontal cortex and hippocampus.
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Affiliation(s)
- Sebastian H Bitzenhofer
- Developmental Neurophysiology, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany
| | - Ileana L Hanganu-Opatz
- Developmental Neurophysiology, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany.
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21
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Katow H, Abe K, Katow T, Zamani A, Abe H. Development of the GABA-ergic signaling system and its role in larval swimming in sea urchin. ACTA ACUST UNITED AC 2013; 216:1704-16. [PMID: 23307803 DOI: 10.1242/jeb.074856] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study aimed to elucidate the development and γ-amino butyric acid (GABA)-ergic regulation of larval swimming in the sea urchin Hemicentrotus pulcherrimus by cloning glutamate decarboxylase (Hp-gad), GABAA receptor (Hp-gabrA) and GABAA receptor-associated protein (Hp-gabarap), and by performing immunohistochemistry. The regulation of larval swimming was increasingly dependent on the GABAergic system, which was active from the 2 days post-fertilization (d.p.f.) pluteus stage onwards. GABA-immunoreactive cells were detected as a subpopulation of secondary mesenchyme cells during gastrulation and eventually constituted the ciliary band and a subpopulation of blastocoelar cells during the pluteus stage. Hp-gad transcription was detected by RT-PCR during the period when Hp-Gad-positive cells were seen as a subpopulation of blastocoelar cells and on the apical side of the ciliary band from the 2 d.p.f. pluteus stage. Consistent with these observations, inhibition of GAD with 3-mercaptopropioninc acid inhibited GABA immunoreactivity and larval swimming dose dependently. Hp-gabrA amplimers were detected weakly in unfertilized eggs and 4 d.p.f. plutei but strongly from fertilized eggs to 2 d.p.f. plutei, and Hp-GabrA, together with GABA, was localized at the ciliary band in association with dopamine receptor D1 from the two-arm pluteus stage. Hp-gabarap transcription and protein expression were detected from the swimming blastula stage. Inhibition of the GABAA receptor by bicuculline inhibited larval swimming dose dependently. Inhibition of larval swimming by either 3-mercaptopropionic acid or bicuculline was more severe in older larvae (17 and 34 d.p.f. plutei) than in younger ones (1 d.p.f. prism larvae).
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Affiliation(s)
- Hideki Katow
- Research Center for Marine Biology, Tohoku University, Asamushi, Aomori, Aomori 039-3501, Japan.
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22
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Boulland JL, Chaudhry FA. Ontogenetic changes in the distribution of the vesicular GABA transporter VGAT correlate with the excitation/inhibition shift of GABA action. Neurochem Int 2012; 61:506-16. [PMID: 22490609 DOI: 10.1016/j.neuint.2012.03.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/19/2012] [Accepted: 03/20/2012] [Indexed: 10/28/2022]
Abstract
GABA is the major inhibitory neurotransmitter in the adult CNS and is among others involved in the synchronization of large neuronal networks. During development, GABA acts as a morphogenetic factor and has transient excitatory actions in many brain regions. One distinct protein, the vesicular GABA transporter (VGAT), has been identified accumulating GABA into presynaptic vesicles prior to its exocytotic release. The function of VGAT and its distribution is well defined in the adult, but its contribution to the transient excitatory action at putative GABAergic nerve terminals in the immature brain and its potential roles in putative glutamatergic nerve terminals remain elusive. We have studied VGAT expression in the brain from late embryonic stages through several postnatal stages until adulthood. Quantitative immunoblotting and immunolabeling of tissue sections at the light microscope and the electron microscope levels show an abrupt augmentation in VGAT staining in the cerebral cortex during the first three postnatal weeks, resembling the increase in other proteins involved in GABA synthesis and recycling in the same time frame - such as GAD65, GAD67, GAT1 (Slc6a1) and SN1 (Slc38a3) - and coincides with the synaptogenetic spurt. Dynamic changes in the expression of VGAT are seen in many cellular populations and in several layers in different brain regions. However, mossy fiber terminals (MFT) elude staining for VGAT. We also demonstrate that VGAT(+) nerve terminals undergo a developmental reorganization so that from targeting primarily the dendrites of the principal neurons in several brain regions in the immature brain, they target the soma of the same cells in the adult. This shift in the targeted subcellular compartment coincides with the conversion of the chloride gradient across neuronal membranes and suggests that it may be important for the shift of GABA action from excitation to inhibition and for the establishment of the potent synchronization of neuronal networks.
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Piccolini V, Cerri S, Romanelli E, Bernocchi G. Interactions of neurotransmitter systems during postnatal development of the rat hippocampal formation: Effects of cisplatin. Exp Neurol 2012; 234:239-52. [DOI: 10.1016/j.expneurol.2011.12.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 12/21/2011] [Accepted: 12/25/2011] [Indexed: 01/14/2023]
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Miraucourt LS, da Silva JS, Burgos K, Li J, Abe H, Ruthazer ES, Cline HT. GABA expression and regulation by sensory experience in the developing visual system. PLoS One 2012; 7:e29086. [PMID: 22242157 PMCID: PMC3252287 DOI: 10.1371/journal.pone.0029086] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 11/21/2011] [Indexed: 01/20/2023] Open
Abstract
The developing retinotectal system of the Xenopus laevis tadpole is a model of choice for studying visual experience-dependent circuit maturation in the intact animal. The neurotransmitter gamma-aminobutyric acid (GABA) has been shown to play a critical role in the formation of sensory circuits in this preparation, however a comprehensive neuroanatomical study of GABAergic cell distribution in the developing tadpole has not been conducted. We report a detailed description of the spatial expression of GABA immunoreactivity in the Xenopus laevis tadpole brain at two key developmental stages: stage 40/42 around the onset of retinotectal innervation and stage 47 when the retinotectal circuit supports visually-guided behavior. During this period, GABAergic neurons within specific brain structures appeared to redistribute from clusters of neuronal somata to a sparser, more uniform distribution. Furthermore, we found that GABA levels were regulated by recent sensory experience. Both ELISA measurements of GABA concentration and quantitative analysis of GABA immunoreactivity in tissue sections from the optic tectum show that GABA increased in response to a 4 hr period of enhanced visual stimulation in stage 47 tadpoles. These observations reveal a remarkable degree of adaptability of GABAergic neurons in the developing brain, consistent with their key contributions to circuit development and function.
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Affiliation(s)
- Loïs S. Miraucourt
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Jorge Santos da Silva
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
| | - Kasandra Burgos
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
- Stony Brook School of Medicine, Stony Brook University, Stony Brook, New York, United States of America
| | - Jianli Li
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, United States of America
- Departments of Cell Biology and Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Hikari Abe
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Edward S. Ruthazer
- Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Hollis T. Cline
- Departments of Cell Biology and Chemical Physiology, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Cheyne JE, Grant L, Butler-Munro C, Foote JW, Connor B, Montgomery JM. Synaptic integration of newly generated neurons in rat dissociated hippocampal cultures. Mol Cell Neurosci 2011; 47:203-14. [DOI: 10.1016/j.mcn.2011.04.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 04/20/2011] [Accepted: 04/26/2011] [Indexed: 10/18/2022] Open
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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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27
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Cserép C, Szonyi A, Veres JM, Németh B, Szabadits E, de Vente J, Hájos N, Freund TF, Nyiri G. Nitric oxide signaling modulates synaptic transmission during early postnatal development. Cereb Cortex 2011; 21:2065-74. [PMID: 21282319 PMCID: PMC3155603 DOI: 10.1093/cercor/bhq281] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Early γ-aminobutyric acid mediated (GABAergic) synaptic transmission and correlated neuronal activity are fundamental to network formation; however, their regulation during early postnatal development is poorly understood. Nitric oxide (NO) is an important retrograde messenger at glutamatergic synapses, and it was recently shown to play an important role also at GABAergic synapses in the adult brain. The subcellular localization and network effect of this signaling pathway during early development are so far unexplored, but its disruption at this early age is known to lead to profound morphological and functional alterations. Here, we provide functional evidence--using whole-cell recording--that NO signaling modulates not only glutamatergic but also GABAergic synaptic transmission in the mouse hippocampus during the early postnatal period. We identified the precise subcellular localization of key elements of the underlying molecular cascade using immunohistochemistry at the light--and electron microscopic levels. As predicted by these morpho-functional data, multineuron calcium imaging in acute slices revealed that this NO-signaling machinery is involved also in the control of synchronous network activity patterns. We suggest that the retrograde NO-signaling system is ideally suited to fulfill a general presynaptic regulatory role and may effectively fine-tune network activity during early postnatal development, while GABAergic transmission is still depolarizing.
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Affiliation(s)
- Csaba Cserép
- Laboratory of Cerebral Cortex Research, Department of Cellular and Network Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Hungary
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Xi S, Guo L, Qi R, Sun W, Jin Y, Sun G. Prenatal and early life arsenic exposure induced oxidative damage and altered activities and mRNA expressions of neurotransmitter metabolic enzymes in offspring rat brain. J Biochem Mol Toxicol 2010; 24:368-78. [DOI: 10.1002/jbt.20349] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Shetty AK, Hattiangady B, Rao MS. Vulnerability of hippocampal GABA-ergic interneurons to kainate-induced excitotoxic injury during old age. J Cell Mol Med 2010. [PMID: 20141618 DOI: 10.1111/j.1582-4934.2008.00675.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Hippocampal inhibitory interneurons expressing glutamate decarboxylase-67 (GAD-67) considerably decline in number during old age. Studies in young adult animals further suggest that hippocampal GAD-67+ interneuron population is highly vulnerable to excitotoxic injury. However, the relative susceptibility of residual GAD-67+ interneurons in the aged hippocampus to excitotoxic injury is unknown. To elucidate this, using both adult and aged F344 rats, we performed stereological counting of GAD-67+ interneurons in different layers of the dentate gyrus and CA1 & CA3 sub-fields, at 3 months post-excitotoxic hippocampal injury inflicted through an intracerebroventricular administration of kainic acid (KA). Substantial reductions of GAD-67+ interneurons were found in all hippocampal layers and sub-fields after KA-induced injury in adult animals. Contrastingly, there was no significant change in GAD-67+ interneuron population in any of the hippocampal layers and sub-fields following similar injury in aged animals. Furthermore, the stability of GAD-67+ interneurons in aged rats after KA was not attributable to milder injury, as the overall extent of KA-induced hippocampal principal neuron loss was comparable between adult and aged rats. Interestingly, because of the age-related disparity in vulnerability of interneurons to injury, the surviving GAD-67+ interneuron population in the injured aged hippocampus remained comparable to that observed in the injured adult hippocampus despite enduring significant reductions in interneuron number with aging. Thus, unlike in the adult hippocampus, an excitotoxic injury to the aged hippocampus does not result in significantly decreased numbers of GAD-67+ interneurons. Persistence of GAD-67+ interneuron population in the injured aged hippocampus likely reflects an age-related change in the response of GAD-67+ interneurons to excitotoxic hippocampal injury. These results have implications towards understanding mechanisms underlying the evolution of initial precipitating injury into temporal lobe epilepsy in the elderly population.
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Affiliation(s)
- Ashok K Shetty
- Medical Research and Surgery Services, Veterans Affairs Medical Center, Durham, NC, USA.
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The organization of feedback projections in a pathway important for processing pheromonal signals. Neuroscience 2009; 161:489-500. [PMID: 19341782 DOI: 10.1016/j.neuroscience.2009.03.065] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 03/23/2009] [Accepted: 03/23/2009] [Indexed: 01/21/2023]
Abstract
In most of the mammalian sensory systems there are massive cortical feedback projections to early processing stations. The mammalian accessory olfactory system is considered unique in several aspects. It is specialized for processing pheromonal signals and plays a critical role in regulating sociosexual behaviors. Furthermore, pheromonal signals are believed to bypass cortex and reach the hypothalamic behavioral centers after merely three forward projections. Because the organization of the feedback projections in the accessory olfactory system remains largely unclear, the importance of the feedback projections in the processing of pheromonal signals has been ignored. Here we show that in mice the feedback projections from the bed nucleus of stria terminalis (BST) and the vomeronasal amygdala to the accessory olfactory bulb (AOB) are topographically organized and use different neurotransmitters. By retrograde and anterograde tracing, we find that the feedback projection from the BST terminates in the AOB mitral cell layer, whereas that from the amygdala terminates in the AOB granule cell layer. By combining tracing, genetic labeling of GABAergic neurons, and immunostaining against a marker of glutamatergic synapses, we observe that the BST-to-AOB projection is GABAergic whereas the amygdala-to-AOB projection is glutamatergic. In addition, a substantial number of feedback neurons in the amygdala and BST express estrogen receptors. Thus, the accessory olfactory system, like other sensory systems, possesses extensive feedback projections. Moreover, our results suggest that central hormonal cues may modulate the processing of pheromonal signals at early stations through the precisely organized feedback projections.
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31
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Popp A, Urbach A, Witte OW, Frahm C. Adult and embryonic GAD transcripts are spatiotemporally regulated during postnatal development in the rat brain. PLoS One 2009; 4:e4371. [PMID: 19190758 PMCID: PMC2629816 DOI: 10.1371/journal.pone.0004371] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Accepted: 12/22/2008] [Indexed: 12/02/2022] Open
Abstract
Background GABA (gamma-aminobutyric acid), the main inhibitory neurotransmitter in the brain, is synthesized by glutamic acid decarboxylase (GAD). GAD exists in two adult isoforms, GAD65 and GAD67. During embryonic brain development at least two additional transcripts exist, I-80 and I-86, which are distinguished by insertions of 80 or 86 bp into GAD67 mRNA, respectively. Though it was described that embryonic GAD67 transcripts are not detectable during adulthood there are evidences suggesting re-expression under certain pathological conditions in the adult brain. In the present study we systematically analyzed for the first time the spatiotemporal distribution of different GADs with emphasis on embryonic GAD67 mRNAs in the postnatal brain using highly sensitive methods. Methodology/Principal Findings QPCR was used to precisely investigate the postnatal expression level of GAD related mRNAs in cortex, hippocampus, cerebellum, and olfactory bulb of rats from P1 throughout adulthood. Within the first three postnatal weeks the expression of both GAD65 and GAD67 mRNAs reached adult levels in hippocampus, cortex, and cerebellum. The olfactory bulb showed by far the highest expression of GAD65 as well as GAD67 transcripts. Embryonic GAD67 splice variants were still detectable at birth. They continuously declined to barely detectable levels during postnatal development in all investigated regions with exception of a comparatively high expression in the olfactory bulb. Radioactive in situ hybridizations confirmed the occurrence of embryonic GAD67 transcripts in the olfactory bulb and furthermore detected their localization mainly in the subventricular zone and the rostral migratory stream. Conclusions/Significance Embryonic GAD67 transcripts can hardly be detected in the adult brain, except for specific regions associated with neurogenesis and high synaptic plasticity. Therefore a functional role in processes like proliferation, migration or synaptogenesis is suggested.
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Affiliation(s)
- Anke Popp
- Department of Neurology, Friedrich-Schiller-University, Jena, Germany
| | - Anja Urbach
- Department of Neurology, Friedrich-Schiller-University, Jena, Germany
| | - Otto W. Witte
- Department of Neurology, Friedrich-Schiller-University, Jena, Germany
| | - Christiane Frahm
- Department of Neurology, Friedrich-Schiller-University, Jena, Germany
- * E-mail:
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32
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Levav T, Wirthaim O, Weiss R, Grossman Y, Golan H. Impaired synaptogenesis and long-term modulation of behavior following postnatal elevation of GABA levels in mice. Neuropharmacology 2007; 54:387-98. [PMID: 18063001 DOI: 10.1016/j.neuropharm.2007.10.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 09/14/2007] [Accepted: 10/17/2007] [Indexed: 11/12/2022]
Abstract
Antiepileptic drugs acting through the potentiation of GABAergic pathways have adverse effects on brain development. Increased risk of impaired intellectual development has been reported in children born to women treated for epilepsy during pregnancy. We have previously shown, in mice, that treatment with the antiepileptic drug vigabatrin (GVG) on postnatal days 4-14 delays reflex development in the newborn and impairs learning and memory in the adult. Here, we report the time course in which postnatal GVG treatment induced behavioral changes in an open field test and had a detrimental developmental effect on recognition memory in mice. Furthermore, GVG treatment significantly modulated the expression of synaptobrevin/vesicle-associated membrane protein (VAMP) II and synaptotagmin (Synt) I. A short-term decrease in the expression of these proteins was followed by a long-term elevation in their expression in both the hippocampus and the cerebral cortex. In contrast, no changes were detected in the levels of Synt II or in the vesicular GABA transporter. The over-expression of VAMP II and Synt I in the GVG-treated mice was associated with a significant decrease in the basal field excitatory postsynaptic potentials (fEPSP) and modulated the response to repeated stimulation. The changes observed in synaptogenesis may explain the behavioral impairment induced by postnatal GVG treatment and may suggest a possible mechanism for the detrimental effect of antiepileptic drugs acting through elevation of GABA levels.
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Affiliation(s)
- Tamar Levav
- Department of Developmental Molecular Genetics, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Hwang IK, Li H, Yoo KY, Choi JH, Lee CH, Chung DW, Kim DW, Seong JK, Yoon YS, Lee IS, Won MH. Comparison of glutamic acid decarboxylase 67 immunoreactive neurons in the hippocampal CA1 region at various age stages in dogs. Neurosci Lett 2007; 431:251-5. [PMID: 18166269 DOI: 10.1016/j.neulet.2007.11.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 11/26/2007] [Accepted: 11/28/2007] [Indexed: 10/22/2022]
Abstract
The hippocampus is a main brain region concerning learning and memory processes. It is imperative to determine the extent of alterations in number and function of inhibitory GABAergic interneurons in the hippocampus as a function of age. We examined changes in GABAergic neurons in the hippocampal CA1 region at various ages of dogs using glutamic acid decarboxylase 67 (GAD67), which is a rate-limiting enzyme for GABA synthesis. We found only one band in the brain homogenates in dogs as well as mice and rats. GAD67 immunoreactive neurons in 1-year-old dogs were mainly detected in the stratum oriens. In the 6-year-old group, GAD67 immunoreactive neurons were evenly distributed in the CA1 region, and numbers of the neurons were highest among all experimental groups. Thereafter, GAD67 immunoreactive neurons were significantly decreased region with age: GAD67 immunoreactive neurons were scarcely found in the CA1 region in 10-year-old dogs. The reduction of GAD67 immunoreactive neurons in the hippocampal CA1 region may be closely related to highly susceptibility to memory loss in old aged dogs.
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Affiliation(s)
- In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul 151-742, South Korea
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Ben-Ari Y, Gaiarsa JL, Tyzio R, Khazipov R. GABA: a pioneer transmitter that excites immature neurons and generates primitive oscillations. Physiol Rev 2007; 87:1215-84. [PMID: 17928584 DOI: 10.1152/physrev.00017.2006] [Citation(s) in RCA: 892] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Developing networks follow common rules to shift from silent cells to coactive networks that operate via thousands of synapses. This review deals with some of these rules and in particular those concerning the crucial role of the neurotransmitter gamma-aminobuytric acid (GABA), which operates primarily via chloride-permeable GABA(A) receptor channels. In all developing animal species and brain structures investigated, neurons have a higher intracellular chloride concentration at an early stage leading to an efflux of chloride and excitatory actions of GABA in immature neurons. This triggers sodium spikes, activates voltage-gated calcium channels, and acts in synergy with NMDA channels by removing the voltage-dependent magnesium block. GABA signaling is also established before glutamatergic transmission, suggesting that GABA is the principal excitatory transmitter during early development. In fact, even before synapse formation, GABA signaling can modulate the cell cycle and migration. The consequence of these rules is that developing networks generate primitive patterns of network activity, notably the giant depolarizing potentials (GDPs), largely through the excitatory actions of GABA and its synergistic interactions with glutamate signaling. These early types of network activity are likely required for neurons to fire together and thus to "wire together" so that functional units within cortical networks are formed. In addition, depolarizing GABA has a strong impact on synaptic plasticity and pathological insults, notably seizures of the immature brain. In conclusion, it is suggested that an evolutionary preserved role for excitatory GABA in immature cells provides an important mechanism in the formation of synapses and activity in neuronal networks.
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Affiliation(s)
- Yehezkel Ben-Ari
- Insititut de Neurobiologie de la Méditerranée, Institut National de la Santé et de la Recherche Médicale U. 29, Marseille, France.
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35
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Di Cristo G, Chattopadhyaya B, Kuhlman SJ, Fu Y, Bélanger MC, Wu CZ, Rutishauser U, Maffei L, Huang ZJ. Activity-dependent PSA expression regulates inhibitory maturation and onset of critical period plasticity. Nat Neurosci 2007; 10:1569-77. [PMID: 18026099 DOI: 10.1038/nn2008] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Accepted: 10/05/2007] [Indexed: 11/09/2022]
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36
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Huang ZJ, Di Cristo G, Ango F. Development of GABA innervation in the cerebral and cerebellar cortices. Nat Rev Neurosci 2007; 8:673-86. [PMID: 17704810 DOI: 10.1038/nrn2188] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In many areas of the vertebrate brain, such as the cerebral and cerebellar cortices, neural circuits rely on inhibition mediated by GABA (gamma-aminobutyric acid) to shape the spatiotemporal patterns of electrical signalling. The richness and subtlety of inhibition are achieved by diverse classes of interneurons that are endowed with distinct physiological properties. In addition, the axons of interneurons display highly characteristic and class-specific geometry and innervation patterns, and thereby distribute their output to discrete spatial domains, cell types and subcellular compartments in neural networks. The cellular and molecular mechanisms that specify and modify inhibitory innervation patterns are only just beginning to be understood.
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Affiliation(s)
- Z J Huang
- Cold Spring Harbour Laboratory, One Bungtown Road, Cold Spring Harbor, New York 11724, USA.
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37
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Holter NI, Zuber N, Bruehl C, Draguhn A. Functional maturation of developing interneurons in the molecular layer of mouse dentate gyrus. Brain Res 2007; 1186:56-64. [PMID: 17996219 DOI: 10.1016/j.brainres.2007.09.089] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2007] [Revised: 09/12/2007] [Accepted: 09/29/2007] [Indexed: 11/20/2022]
Abstract
The dentate gyrus is the main target for cortical inputs to the hippocampal formation and is particularly strongly controlled by synaptic inhibition. Many GABAergic interneurons migrate from the dentate molecular layer towards their final position in the hilus during the first two postnatal weeks. During this critical period of development we monitored the intrinsic and synaptic properties of developing interneurons in the molecular layer of mouse hippocampal slices. We focussed on multipolar cells in the middle portion of the molecular layer. With increasing age, input resistance decreased and action potential waveform changed to larger amplitude and shorter duration. Repetitive spiking was scarce at early stages, while trains of action potentials could be readily elicited after the first postnatal week. At all ages, we observed spontaneous postsynaptic currents which were almost exclusively GABA(A) receptor-mediated and increased in frequency with age. All developmental changes in intrinsic and synaptic properties occurred between p 6-8 and p 9-11, indicating a rapid functional maturation at the end of the first postnatal week. Parallel immunohistochemical experiments revealed that calretinin positive cells formed the major part of developing interneurons in the middle molecular layer. Together, the data shows a rapid functional maturation of intrinsic and synaptic properties of interneurons in the dentate molecular layer and an early integration into synaptic networks with clear prevalence of inhibitory synaptic inputs.
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Affiliation(s)
- Nadine I Holter
- Institut für Physiologie und Pathophysiologie, Fakultät für Medizin, Universität Heidelberg, Im Neuenheimer Feld 326, Heidelberg, Germany
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38
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Chattopadhyaya B, Di Cristo G, Wu CZ, Knott G, Kuhlman S, Fu Y, Palmiter RD, Huang ZJ. GAD67-mediated GABA synthesis and signaling regulate inhibitory synaptic innervation in the visual cortex. Neuron 2007; 54:889-903. [PMID: 17582330 PMCID: PMC2077924 DOI: 10.1016/j.neuron.2007.05.015] [Citation(s) in RCA: 239] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 12/15/2006] [Accepted: 05/04/2007] [Indexed: 11/17/2022]
Abstract
The development of GABAergic inhibitory circuits is shaped by neural activity, but the underlying mechanisms are unclear. Here, we demonstrate a novel function of GABA in regulating GABAergic innervation in the adolescent brain, when GABA is mainly known as an inhibitory transmitter. Conditional knockdown of the rate-limiting synthetic enzyme GAD67 in basket interneurons in adolescent visual cortex resulted in cell autonomous deficits in axon branching, perisomatic synapse formation around pyramidal neurons, and complexity of the innervation fields; the same manipulation had little influence on the subsequent maintenance of perisomatic synapses. These effects of GABA deficiency were rescued by suppressing GABA reuptake and by GABA receptor agonists. Germline knockdown of GAD67 but not GAD65 showed similar deficits, suggesting a specific role of GAD67 in the maturation of perisomatic innervation. Since intracellular GABA levels are modulated by neuronal activity, our results implicate GAD67-mediated GABA synthesis in activity-dependent regulation of inhibitory innervation patterns.
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Affiliation(s)
- Bidisha Chattopadhyaya
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
- Neuroscience Program, State University of New York, Stony Brook, NY 11790, USA
| | | | - Cai Zhi Wu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Graham Knott
- Institute de Biologie Cellularie et de Morphologie, University of Lausanne, Switzerland CH 1005
| | - Sandra Kuhlman
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Yu Fu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
- Neuroscience Program, State University of New York, Stony Brook, NY 11790, USA
| | - Richard D. Palmiter
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Z. Josh Huang
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
- * corresponding author:
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39
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Inverardi F, Beolchi MS, Ortino B, Moroni RF, Regondi MC, Amadeo A, Frassoni C. GABA immunoreactivity in the developing rat thalamus and Otx2 homeoprotein expression in migrating neurons. Brain Res Bull 2007; 73:64-74. [PMID: 17499638 DOI: 10.1016/j.brainresbull.2007.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 02/05/2007] [Accepted: 02/06/2007] [Indexed: 10/23/2022]
Abstract
We investigated the expression of gamma-aminobutyric acid (GABA) in the developing rat thalamus by immunohistochemistry, using light, confocal and electron microscopy. We also examined the relationship between the expression of the homeoprotein Otx2, a transcription factor implicated in brain regionalization, and the radial and non-radial migration of early generated thalamic neurons, identified by the neuronal markers calretinin (CR) and GABA. The earliest thalamic neurons generated between embryonic days (E) 13 and 15 include those of the reticular nucleus, entirely composed by GABAergic neurons. GABA immunoreactivity appeared at E14 in immature neurons and processes laterally to the neuroepithelium of the diencephalic vesicle. The embryonic and perinatal periods were characterized by the presence of abundant GABA-immunoreactive fibers, mostly tangentially oriented, and of growth cones. At E15 and E16, GABA was expressed in radially and non-radially oriented neurons in the region of the reticular thalamic migration, between the dorsal and ventral thalamic primordia, and within the dorsal thalamus. At these embryonic stages, some CR- and GABA-immunoreactive migrating-like neurons, located in the migratory stream and in the dorsal thalamus, expressed the homeoprotein Otx2. In the perinatal period, the preponderance of GABAergic neurons was restricted to the reticular nucleus and several GABAergic fibers were still detectable throughout the thalamus. The immunolabeling of fibers progressively decreased and was no longer visible by postnatal day 10, when the adult configuration of GABA immunostaining was achieved. These results reveal the spatio-temporal features of GABA expression in the developing thalamus and suggest a novel role of Otx2 in thalamic cell migration.
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Affiliation(s)
- F Inverardi
- Dipartimento di Epilettologia Clinica e Neurofisiologia Sperimentale, Fondazione I.R.C.C.S. Istituto Nazionale Neurologico C. Besta, via Celoria 11, 20133 Milano, Italy
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40
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Abstract
Interneurons are GABAergic neurons responsible for inhibitory activity in the adult hippocampus, thereby controlling the activity of principal excitatory cells through the activation of postsynaptic GABAA receptors. Subgroups of GABAergic neurons innervate specific parts of excitatory neurons. This specificity indicates that particular interneuron subgroups are able to recognize molecules segregated on the membrane of the pyramidal neuron. Once these specific connections are established, a quantitative regulation of their strength must be performed to achieve the proper balance of excitation and inhibition. We will review when and where interneurons are generated. We will then detail their migration toward and within the hippocampus, and the maturation of their morphological and neurochemical characteristics. We will finally review potential mechanisms underlying the development of GABAergic interneurons.
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Affiliation(s)
- Lydia Danglot
- Laboratoire de Biologie de la Synapse Normale et Pathologique, Unité Inserm U789, Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France.
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41
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Swanwick CC, Murthy NR, Mtchedlishvili Z, Sieghart W, Kapur J. Development of gamma-aminobutyric acidergic synapses in cultured hippocampal neurons. J Comp Neurol 2006; 495:497-510. [PMID: 16498682 PMCID: PMC2742963 DOI: 10.1002/cne.20897] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The formation and maturation of gamma-aminobutyric acid (GABA)-ergic synapses was studied in cultured hippocampal pyramidal neurons by both performing immunocytochemistry for GABAergic markers and recording miniature inhibitory postsynaptic currents (mIPSCs). Nascent GABAergic synapses appeared between 3 and 8 days in vitro (DIV), with GABAA receptor subunit clusters appearing first, followed by GAD-65 puncta, then functional synapses. The number of GABAergic synapses increased from 7 to 14 DIV, with a corresponding increase in frequency of mIPSCs. Moreover, these new GABAergic synapses formed on neuronal processes farther from the soma, contributing to decreased mIPSC amplitude and slowed mIPSC 19-90% rise time. The mIPSC decay quickened from 7 to 14 DIV, with a parallel change in the distribution of the alpha5 subunit from diffuse expression at 7 DIV to clustered expression at 14 DIV. These alpha5 clusters were mostly extrasynaptic. The alpha1 subunit was expressed as clusters in none of the neurons at 7 DIV, in 20% at 14 DIV, and in 80% at 21 DIV. Most of these alpha1 clusters were expressed at GABAergic synapses. In addition, puncta of GABA transporter 1 (GAT-1) were localized to GABAergic synapses at 14 DIV but were not expressed at 7 DIV. These studies demonstrate that mIPSCs appear after pre- and postsynaptic elements are in place. Furthermore, the process of maturation of GABAergic synapses involves increased synapse formation at distal processes, expression of new GABAA receptor subunits, and GAT-1 expression at synapses; these changes are reflected in altered frequency, kinetics, and drug sensitivity of mIPSCs.
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Affiliation(s)
| | - Namita R. Murthy
- College of Arts and Sciences, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Werner Sieghart
- Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Jaideep Kapur
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22908, USA
- Dept. of Neurology, University of Virginia, Charlottesville, VA 22908, USA
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Frassoni C, Inverardi F, Coco S, Ortino B, Grumelli C, Pozzi D, Verderio C, Matteoli M. Analysis of SNAP-25 immunoreactivity in hippocampal inhibitory neurons during development in culture and in situ. Neuroscience 2005; 131:813-23. [PMID: 15749336 DOI: 10.1016/j.neuroscience.2004.11.042] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2004] [Indexed: 11/23/2022]
Abstract
Synaptosomal associated protein of 25 kDa (SNAP-25) is a component of the soluble N-ethylmaleimide-sensitive fusion protein (NSF) attachment protein receptor (SNARE) complex which plays a central role in synaptic vesicle exocytosis. We have previously demonstrated that adult rat hippocampal GABAergic synapses, both in culture and in brain, are virtually devoid of SNAP-25 immunoreactivity and are less sensitive to the action of botulinum toxin type A, which cleaves this SNARE protein [Neuron 41 (2004) 599]. In the present study, we extend our findings to the adult mouse hippocampus and we also provide demonstration that hippocampal inhibitory synapses lacking SNAP-25 labeling belong to parvalbumin-, calretinin- and cholecystokinin-positive interneurons. A partial colocalization between SNAP-25 and glutamic acid decarboxylase is instead detectable in developing mouse hippocampus at P0 and, at a lesser extent, at P5. In rat embryonic hippocampal cultures at early developmental stages, SNAP-25 immunoreactivity is detectable in a percentage of GABAergic neurons, which progressively reduces with time in culture. Consistent with the presence of the substrate, botulinum toxin type A is partially effective in inhibiting synaptic vesicle recycling in immature GABAergic neurons. Since SNAP-25, beside its role as a SNARE protein, is involved in additional processes, such as neurite outgrowth and regulation of calcium dynamics, the presence of higher levels of the protein at specific stages of neuronal differentiation may have implications for the construction and for the functional properties of brain circuits.
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Affiliation(s)
- C Frassoni
- Department of Medical Pharmacology, CNR Institute of Neuroscience, University of Milano, Center of Excellence on Neurodegenerative Diseases, Milano, Italy
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43
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Mangan PS, Sun C, Carpenter M, Goodkin HP, Sieghart W, Kapur J. Cultured Hippocampal Pyramidal Neurons Express Two Kinds of GABAA Receptors. Mol Pharmacol 2004; 67:775-88. [PMID: 15613639 DOI: 10.1124/mol.104.007385] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We combined a study of the subcellular distribution of the alpha1, alpha2, alpha4, beta1, beta2/3, gamma2, and delta subunits of the GABAA receptor with an electrophysiological analysis of GABAA receptor currents determine the to types of receptors expressed on cultured hippocampal pyramidal neurons. The immunocytochemistry study demonstrated that alpha1, alpha2, beta2/3, and gamma2 subunits formed distinct clusters of various sizes, which were colocalized with clusters of glutamate decarboxylase (GAD) immunoreactivity at rates ranging from 22 to 58%. In contrast, alpha4, beta1, and delta subunits were distributed diffusely over the cell soma and neuronal processes of cultured neurons and did not colocalize with the synaptic marker GAD. Whole-cell GABA receptor currents were moderately sensitive to GABAA and were modulated by diazepam. The whole-cell currents were also enhanced by the neurosteroid allopregnanolone (10 nM). Tonic currents, measured as changes in baseline current and noise, were sensitive to Zn2+, furosemide, and loreclezole; they were insensitive to diazepam. These studies suggest that two kinds of GABAA receptors are expressed on cultured hippocampal neurons. One kind of receptor formed clusters, which were present at GABAergic synapses and in the extrasynaptic membrane. The alpha1, alpha2, beta2/3, and gamma2 subunits were contained in clustered receptors. The second kind was distributed diffusely in the extrasynaptic membrane. The alpha4, beta1, and delta subunits were contained in these diffusely distributed receptors. The properties of tonic currents recorded from these neurons were similar to those from recombinant receptors containing alpha4, beta1, and delta subunits.
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Affiliation(s)
- Patrick S Mangan
- Department of Neurology, Box 800394, University of Virginia-HSC, Charlottesville, VA, USA
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44
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Shi L, Argenta AE, Winseck AK, Brunso-Bechtold JK. Stereological quantification of GAD-67-immunoreactive neurons and boutons in the hippocampus of middle-aged and old Fischer 344 x Brown Norway rats. J Comp Neurol 2004; 478:282-91. [PMID: 15368530 DOI: 10.1002/cne.20303] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The aging process in rodents is associated with learning and memory impairments that are correlated with changes in multiple neurotransmitter systems in the hippocampus. For example, the gamma-aminobutyric acid (GABA)ergic system is compromised in old compared with young rats (Shetty and Turner [1998] J. Comp. Neurol. 394:252-269; Vela et al. [2003] J. Neurochem. 85:368-377; Potier et al. [1992] Neuroscience 48:793-806; Potier et al. [1994] Brain Res. 661:181-188). The present study investigated the important issue of whether there is a decline of the GABAergic inhibitory system between middle and old age. Five middle-aged (15-17 months) and five old (25-29 months) Fischer 344 x Brown Norway male rats were perfused, and coronal sections through the dorsal hippocampus were immunoreacted with antibodies either to NeuN, a neuronal marker, or to the 67-kDa isoform of glutamic acid decarboxylase (GAD), the rate-limiting enzyme for GABA synthesis. Using the optical dissector technique, NeuN-immunoreactive (IR) cells, GAD-IR cells, and GAD-IR boutons were quantified stereologically in the dentate gyrus, CA3, and CA1. The resulting GAD-IR cell and GAD-IR bouton densities then were normalized to NeuN-IR cell density to exclude the possible confound of tissue shrinkage. The results revealed a significant decline in GAD-IR cells between middle and old age in CA1 but not in dentate gyrus or CA3. Interestingly, GAD-IR boutons did not show a decline in CA1, CA3, or dentate gyrus between middle and old age. It is possible that loss of CA1 inhibitory interneurons in the dorsal hippocampus contributes to the learning and memory impairments reported in old rats.
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Affiliation(s)
- Lei Shi
- Department of Neurobiology & Anatomy, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, North Carolina 27157-1010, USA.
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Kato-Negishi M, Muramoto K, Kawahara M, Kuroda Y, Ichikawa M. Developmental changes of GABAergic synapses formed between primary cultured cortical neurons. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2004; 152:99-108. [PMID: 15351497 DOI: 10.1016/j.devbrainres.2004.05.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/31/2004] [Indexed: 11/29/2022]
Abstract
The characteristics of functional changes of GABAergic synapses between cultured rat cortical neurons were observed by monitoring intracellular calcium level ([Ca2+]in) during development in vitro. After 5 days in vitro (DIV), cultured cortical neurons spontaneously exhibited synchronous oscillatory changes in [Ca2+]in, which were derived from synaptic activity. Exposure to bicuculline, antagonist of gamma-aminobutyric acid (GABA)(A) receptors, caused a marked decrease in the frequency of [Ca2+]in oscillations at 7-20 DIV. Although the frequency of spontaneous oscillations increased during this culture period, the ratio of the decrease in the frequency following bicuculline treatment did not significantly change. Thereafter, to investigate the detailed morphological changes of GABAergic synapses during development in vitro, the cultured neurons were immunostained with antibodies to glutamic acid decarboxylase (GAD), synaptophysin and GABA(A) receptor and were observed under a confocal laser microscope. Most of the GAD-positive puncta colocalized with synaptophysin-positive puncta and were opposed to GABA(A) receptor-positive structures. The images of GAD-positive puncta were reconstructed from the confocal three-dimensional data to analyze their number, volume, and surface area. The number of these puncta increased with culture time at 7-20 DIV. Although the volume of individual GAD-positive puncta did not significantly change, the surface area decreased in a time-dependent manner over the culture period. This system that we developed enabled us to investigate in detail the morphological and functional changes of GABAergic synapses during neuronal development.
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Affiliation(s)
- Midori Kato-Negishi
- Laboratory of Anatomy and Cell Biology, Department of Basic Technique and Facilities, Tokyo Metropolitan Institute for Neuroscience, Tokyo Metropolitan Organization for Medical Research, 2-6 Musashi-dai, Fuchu, Tokyo 183-8526, Japan.
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46
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Abstract
Despite a rather long migratory journey, interneurons are functional before vertically migrating pyramidal neurons and they constitute the source and target of the first functional synapses in the developing hippocampus. Interneuron-driven network patterns are already present in utero while principal cells are mostly quiescent. At that early stage, GABAergic synapses--which are formed before glutamatergic ones--are excitatory, suggesting that GABA is a pioneer, much like the neurons from which it is released. This review discusses this sequence of events, its functional significance and the role that interneurons might play in the construction of cortical networks.
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Affiliation(s)
- Yehezkel Ben-Ari
- Institut de Neurobiologie de la Méditerranée (INMED), Parc Scientifique de Luminy, BP13, 13009 Marseille, France.
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Levav T, Saar T, Berkovich L, Golan H. Perinatal exposure to GABA‐transaminase inhibitor impaired psychomotor function in the developing and adult mouse. Int J Dev Neurosci 2004; 22:137-47. [PMID: 15140467 DOI: 10.1016/j.ijdevneu.2004.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Revised: 03/16/2004] [Accepted: 03/17/2004] [Indexed: 10/26/2022] Open
Abstract
Antiepileptic drugs acting through the potentiation of GABA-ergic pathways have harmful effects on brain development. Increased risk of impaired intellectual development was reported in children born to women treated for epilepsy during pregnancy. Here we examined the vulnerability of the developing brain to treatment with one of the new antiepileptic drugs--vigabatrin--during two time periods in newborn mice (postnatal days 1-7 and 4-14) which parallel the third trimester of human embryo brain development. Delayed development of sensory and motor reflexes, reduced mobility in the open field, impaired object recognition and deficient spatial learning and memory were observed independently of the treatment period. On the contrary, specific susceptibility to the age of exposure was detected in various motor functions. A number of morphological correlates may explain these behavioral alterations; a transient increase in CA1 pyramidal cell layer (P < 0.001) and decrease in granular cell layer (P < 0.05) in hippocampus were detected at postnatal day 7. In addition, a significantly lower cell density was observed in the adult mouse brain in all layers of the M2 cerebral cortex of mice treated during days 4-14, compared to the controls (P < 0.05). Our findings demonstrated short- and long-term deleterious effects of vigabatrin treatment and suggest a specific vulnerability of the developing motor system to GABA enhancement during the first postnatal week.
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Affiliation(s)
- T Levav
- Department of Developmental Molecular Genetics, Faculty of Health Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, 84105 Beer-Sheva, Israel
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48
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Tamamaki N, Yanagawa Y, Tomioka R, Miyazaki JI, Obata K, Kaneko T. Green fluorescent protein expression and colocalization with calretinin, parvalbumin, and somatostatin in the GAD67-GFP knock-in mouse. J Comp Neurol 2004; 467:60-79. [PMID: 14574680 DOI: 10.1002/cne.10905] [Citation(s) in RCA: 1023] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Gamma-aminobutyric acid (GABA)ergic neurons in the central nervous system regulate the activity of other neurons and play a crucial role in information processing. To assist an advance in the research of GABAergic neurons, here we produced two lines of glutamic acid decarboxylase-green fluorescence protein (GAD67-GFP) knock-in mouse. The distribution pattern of GFP-positive somata was the same as that of the GAD67 in situ hybridization signal in the central nervous system. We encountered neither any apparent ectopic GFP expression in GAD67-negative cells nor any apparent lack of GFP expression in GAD67-positive neurons in the two GAD67-GFP knock-in mouse lines. The timing of GFP expression also paralleled that of GAD67 expression. Hence, we constructed a map of GFP distribution in the knock-in mouse brain. Moreover, we used the knock-in mice to investigate the colocalization of GFP with NeuN, calretinin (CR), parvalbumin (PV), and somatostatin (SS) in the frontal motor cortex. The proportion of GFP-positive cells among NeuN-positive cells (neocortical neurons) was approximately 19.5%. All the CR-, PV-, and SS-positive cells appeared positive for GFP. The CR-, PV, and SS-positive cells emitted GFP fluorescence at various intensities characteristics to them. The proportions of CR-, PV-, and SS-positive cells among GFP-positive cells were 13.9%, 40.1%, and 23.4%, respectively. Thus, the three subtypes of GABAergic neurons accounted for 77.4% of the GFP-positive cells. They accounted for 6.5% in layer I. In accord with unidentified GFP-positive cells, many medium-sized spherical somata emitting intense GFP fluorescence were observed in layer I.
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Affiliation(s)
- Nobuaki Tamamaki
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
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Morozov YM, Freund TF. Postnatal development and migration of cholecystokinin-immunoreactive interneurons in rat hippocampus. Neuroscience 2003; 120:923-39. [PMID: 12927199 DOI: 10.1016/s0306-4522(03)00409-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The development of cholecystokinin-immunoreactive (CCK-IR) interneurons in the rat hippocampus was studied using immunocytochemical methods at the light and electron microscopic levels from early (P0-P8) to later postnatal (P12-P20) periods. The laminar distribution of CCK-IR cell bodies changed considerably during the studied period, which is suggested to be due to migration. CCK-IR cells appear to move from the molecular layer of the dentate gyrus to their final destination at the stratum granulosum/hilus border, and tend to concentrate in the distal third of stratum radiatum in CA1-3. The density of CCK-IR cells is rapidly decreasing during the first 4 postnatal days without any apparent reduction in their total number, therefore it is due to the pronounced growth of hippocampal volume in this period. Axons of CCK-IR interneurons formed symmetrical synapses already at P0, and by far the predominant targets were dendrites of presumed principal cells in all subfields of the hippocampus. These axon arbors began to concentrate around pyramidal cell bodies only at P8, at earlier ages CCK-IR axons crossed stratum pyramidale at right angles, and gave rise to varicose collaterals only outside this layer. The dendrites and somata of CCK-IR cells received synapses already at P0, but those were mostly symmetrical, apart from a few immature asymmetrical synapses. At P4, mature asymmetrical synapses with considerable amounts of synaptic vesicles were already commonly encountered. Thus, the innervation of CCK-IR interneurons apparently develops later than their output synapses, suggesting that they may be able to release transmitter before receiving any considerable excitatory drive. We conclude that CCK-IR cells represent one, if not the major, interneuron type that assists in the maturation of glutamatergic synapses (activation of N-methyl-D-aspartate receptors) via GABAergic depolarization of principal cell dendrites, and may contribute to the generation of giant depolarizing potentials. CCK-IR cells will change their function to perisomatic hyperpolarizing inhibition, as glutamatergic transmission in the network becomes operational.
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Affiliation(s)
- Y M Morozov
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083, Budapest, Hungary
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Morozov YM, Freund TF. Post-natal development of type 1 cannabinoid receptor immunoreactivity in the rat hippocampus. Eur J Neurosci 2003; 18:1213-22. [PMID: 12956720 DOI: 10.1046/j.1460-9568.2003.02852.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Type 1 cannabinoid receptors, selectively located on axon terminals of GABAergic interneurons in the hippocampus, are known to be involved in endocannabinoid-mediated retrograde synaptic signalling. The question arises whether type 1 cannabinoid receptors appear on these axons during early post-natal life, when GABAergic transmission is still depolarizing, and whether there are any developmental changes in the cellular or subcellular expression pattern. Here we demonstrate, using single and double immunocytochemical methods at the light and electron microscopic levels, that type 1 cannabinoid receptors are expressed only on the membrane of axon terminals and pre-terminal axons but not on the soma-dendritic membrane at all examined timepoints between post-natal days 0 and 20, similar to the adult distribution. All type 1 cannabinoid receptor-positive boutons formed symmetric synapses. Granular labelling in the somata was already strong at post-natal day 0 and corresponded to multivesicular bodies, lysosomes, Golgi apparatus and rough endoplasmic reticulum. The type 1 cannabinoid receptor-positive axons were shown to originate largely from cholecystokinin-immunoreactive basket and bistratified neurons throughout the hippocampus (90% of all type 1 cannabinoid receptor-containing cells) and dentate gyrus (70% of all type 1 cannabinoid receptor-containing cells). The remaining cells have not been identified but probably belong to the somatostatin- and/or neuropeptide Y-containing subsets, as cholecystokinin-negative, type 1 cannabinoid receptor-positive axons have been observed in strata moleculare and lacunosum-moleculare of the dentate gyrus and CA1-3, respectively, where these neurons are known to arborize. No cell types were found that expressed type 1 cannabinoid receptors transiently at some developmental stage. We conclude that the cellular and subcellular pattern of type 1 cannabinoid receptor expression during early post-natal life is similar to the adult pattern and type 1 cannabinoid receptors are expressed on the cholecystokinin-containing axons as soon as synapse formation begins. This suggests that retrograde synaptic signalling by endocannabinoids is required for the normal operation of GABAergic neurotransmission even before it becomes hyperpolarizing.
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Affiliation(s)
- Yury M Morozov
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Szigony u 43, H-1083 Hungary
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