1
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Wang T, Chen S, Mao Z, Shang Y, Brinton RD. Allopregnanolone pleiotropic action in neurons and astrocytes: calcium signaling as a unifying mechanism. Front Endocrinol (Lausanne) 2023; 14:1286931. [PMID: 38189047 PMCID: PMC10771836 DOI: 10.3389/fendo.2023.1286931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/13/2023] [Indexed: 01/09/2024] Open
Abstract
Objective Allopregnanolone (Allo) is a neurosteroid with pleiotropic action in the brain that includes neurogenesis, oligogenesis, human and rodent neural stem cell regeneration, increased glucose metabolism, mitochondrial respiration and biogenesis, improved cognitive function, and reduction of both inflammation and Alzheimer's disease (AD) pathology. Because the breadth of Allo-induced responses requires activation of multiple systems of biology in the absence of an Allo-specific nuclear receptor, analyses were conducted in both neurons and astrocytes to identify unifying systems and signaling pathways. Methods Mechanisms of Allo action were investigated in embryonic hippocampal neurons and astrocytes cultured in an Aging Model (AM) media. Cellular morphology, mitochondrial function, and transcriptomics were investigated followed by mechanistic pathway analyses. Results In hippocampal neurons, Allo significantly increased neurite outgrowth and synaptic protein expression, which were paralleled by upregulated synaptogenesis and long-term potentiation gene expression profiles. Mechanistically, Allo induced Ca2+/CREB signaling cascades. In parallel, Allo significantly increased maximal mitochondrial respiration, mitochondrial membrane potential, and Complex IV activity while reducing oxidative stress, which required both the GABAA and L-type Ca2+ channels. In astrocytes, Allo increased ATP generation, mitochondrial function and dynamics while reducing oxidative stress, inflammasome indicators, and apoptotic signaling. Mechanistically, Allo regulation of astrocytic mitochondrial function required both the GABAA and L-type Ca2+ channels. Furthermore, Allo activated NRF1-TFAM signaling and increased the DRP1/OPA1 protein ratio, which led to increased mitochondrial biogenesis and dynamics. Conclusion Collectively, the cellular, mitochondrial, transcriptional, and pharmacological profiles provide evidence in support of calcium signaling as a unifying mechanism for Allo pleiotropic actions in the brain.
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Affiliation(s)
- Tian Wang
- Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States
- Department of Neurology, College of Medicine Tucson, University of Arizona, Tucson, AZ, United States
| | - Shuhua Chen
- Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States
| | - Zisu Mao
- Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States
| | - Yuan Shang
- Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States
| | - Roberta Diaz Brinton
- Center for Innovation in Brain Science, University of Arizona, Tucson, AZ, United States
- Department of Neurology, College of Medicine Tucson, University of Arizona, Tucson, AZ, United States
- Department of Pharmacology, College of Medicine Tucson, University of Arizona, Tucson, AZ, United States
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2
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Gulati K, Manukonda R, Kairamkonda M, Kaliki S, Poluri KM. Serum Metabolomics of Retinoblastoma: Assessing the Differential Serum Metabolic Signatures of Unilateral and Bilateral Patients. ACS OMEGA 2023; 8:48233-48250. [PMID: 38144138 PMCID: PMC10733957 DOI: 10.1021/acsomega.3c07424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/17/2023] [Accepted: 11/27/2023] [Indexed: 12/26/2023]
Abstract
Retinoblastoma (Rb) is the most common pediatric eye cancer. To identify the biomarkers for early diagnosis and monitoring the progression of Rb in patients, mapping of the alterations in their metabolic profiles is essential. The present study aims at exploring the metabolic disparity in serum from Rb patients and controls using NMR-based metabolomics. A total of 72 metabolites, including carbohydrates, amino acids, and organic acids, were quantified in serum samples from 24 Rb patients and 26 controls. Distinct clusters of Rb patients and controls were obtained using the partial least-squares discriminant analysis (PLS-DA) model. Further, univariate and multivariate analyses of unilateral and bilateral Rb patients with respect to their age-matched controls depicted their distinct metabolic fingerprints. Metabolites including 2-phosphoglycerate, 4-aminobutyrate, proline, O-phosphocholine, O-phosphoethanolamine, and Sn-glycero-3-phosphocholine (Sn-GPC) showed significant perturbation in both unilateral and bilateral Rb patients. However, metabolic differences among the bilateral Rb cases were more pronounced than those in unilateral Rb cases with respect to controls. In addition to major discriminatory metabolites for Rb, unilateral and bilateral Rb cases showed specific metabolic changes, which might be the result of their differential genetic/somatic mutational backgrounds. This further suggests that the aberrant metabolic perturbation in bilateral patients signifies the severity of the disease in Rb patients. The present study demonstrated that identified serum metabolites have potential to serve as a noninvasive method for detection of Rb, discriminate bilateral from unilateral Rb patients, and aid in better understanding of the RB tumor biology.
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Affiliation(s)
- Khushboo Gulati
- The
Operation Eyesight Universal Institute for Eye Cancer, LV Prasad Eye Institute, Hyderabad-500034, Telangana, India
- Brien
Holden Eye Research Center, L. V. Prasad
Eye Institute, Hyderabad-500034, Telangana, India
| | - Radhika Manukonda
- The
Operation Eyesight Universal Institute for Eye Cancer, LV Prasad Eye Institute, Hyderabad-500034, Telangana, India
- Brien
Holden Eye Research Center, L. V. Prasad
Eye Institute, Hyderabad-500034, Telangana, India
| | - Manikyaprabhu Kairamkonda
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
| | - Swathi Kaliki
- The
Operation Eyesight Universal Institute for Eye Cancer, LV Prasad Eye Institute, Hyderabad-500034, Telangana, India
| | - Krishna Mohan Poluri
- Department
of Biosciences and Bioengineering, Indian
Institute of Technology Roorkee, Roorkee-247667, Uttarakhand, India
- Centre
for Nanotechnology, Indian Institute of
Technology Roorkee, Roorkee-247667, Uttarakhand, India
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3
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The GABA and GABA-Receptor System in Inflammation, Anti-Tumor Immune Responses, and COVID-19. Biomedicines 2023; 11:biomedicines11020254. [PMID: 36830790 PMCID: PMC9953446 DOI: 10.3390/biomedicines11020254] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/16/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
GABA and GABAA-receptors (GABAA-Rs) play major roles in neurodevelopment and neurotransmission in the central nervous system (CNS). There has been a growing appreciation that GABAA-Rs are also present on most immune cells. Studies in the fields of autoimmune disease, cancer, parasitology, and virology have observed that GABA-R ligands have anti-inflammatory actions on T cells and antigen-presenting cells (APCs), while also enhancing regulatory T cell (Treg) responses and shifting APCs toward anti-inflammatory phenotypes. These actions have enabled GABAA-R ligands to ameliorate autoimmune diseases, such as type 1 diabetes (T1D), multiple sclerosis (MS), and rheumatoid arthritis, as well as type 2 diabetes (T2D)-associated inflammation in preclinical models. Conversely, antagonism of GABAA-R activity promotes the pro-inflammatory responses of T cells and APCs, enhancing anti-tumor responses and reducing tumor burden in models of solid tumors. Lung epithelial cells also express GABA-Rs, whose activation helps maintain fluid homeostasis and promote recovery from injury. The ability of GABAA-R agonists to limit both excessive immune responses and lung epithelial cell injury may underlie recent findings that GABAA-R agonists reduce the severity of disease in mice infected with highly lethal coronaviruses (SARS-CoV-2 and MHV-1). These observations suggest that GABAA-R agonists may provide off-the-shelf therapies for COVID-19 caused by new SARS-CoV-2 variants, as well as novel beta-coronaviruses, which evade vaccine-induced immune responses and antiviral medications. We review these findings and further advance the notions that (1) immune cells possess GABAA-Rs to limit inflammation in the CNS, and (2) this natural "braking system" on inflammatory responses may be pharmacologically engaged to slow the progression of autoimmune diseases, reduce the severity of COVID-19, and perhaps limit neuroinflammation associated with long COVID.
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4
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Rurak GM, Woodside B, Aguilar-Valles A, Salmaso N. Astroglial cells as neuroendocrine targets in forebrain development: Implications for sex differences in psychiatric disease. Front Neuroendocrinol 2021; 60:100897. [PMID: 33359797 DOI: 10.1016/j.yfrne.2020.100897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/05/2020] [Accepted: 12/15/2020] [Indexed: 12/23/2022]
Abstract
Astroglial cells are the most abundant cell type in the mammalian brain. They are implicated in almost every aspect of brain physiology, including maintaining homeostasis, building and maintaining the blood brain barrier, and the development and maturation of neuronal networks. Critically, astroglia also express receptors for gonadal sex hormones, respond rapidly to gonadal hormones, and are able to synthesize hormones. Thus, they are positioned to guide and mediate sexual differentiation of the brain, particularly neuronal networks in typical and pathological conditions. In this review, we describe astroglial involvement in the organization and development of the brain, and consider known sex differences in astroglial responses to understand how astroglial cell-mediated organization may play a role in forebrain sexual dimorphisms in human populations. Finally, we consider how sexually dimorphic astroglial responses and functions in development may lead to sex differences in vulnerability for neuropsychiatric disorders.
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Affiliation(s)
- Gareth M Rurak
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| | - Barbara Woodside
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada; Concordia University, Montreal, Quebec, Canada
| | | | - Natalina Salmaso
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada.
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5
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Diverse Actions of Astrocytes in GABAergic Signaling. Int J Mol Sci 2019; 20:ijms20122964. [PMID: 31216630 PMCID: PMC6628243 DOI: 10.3390/ijms20122964] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/10/2019] [Accepted: 06/14/2019] [Indexed: 01/06/2023] Open
Abstract
An imbalance of excitatory and inhibitory neurotransmission leading to over excitation plays a crucial role in generating seizures, while enhancing GABAergic mechanisms are critical in terminating seizures. In recent years, it has been reported in many studies that astrocytes are deeply involved in synaptic transmission. Astrocytes form a critical component of the “tripartite” synapses by wrapping around the pre- and post-synaptic elements. From this location, astrocytes are known to greatly influence the dynamics of ions and transmitters in the synaptic cleft. Despite recent extensive research on excitatory tripartite synapses, inhibitory tripartite synapses have received less attention, even though they influence inhibitory synaptic transmission by affecting chloride and GABA concentration dynamics. In this review, we will discuss the diverse actions of astrocytic chloride and GABA homeostasis at GABAergic tripartite synapses. We will then consider the pathophysiological impacts of disturbed GABA homeostasis at the tripartite synapse.
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6
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Tao R, Davis KN, Li C, Shin JH, Gao Y, Jaffe AE, Gondré-Lewis MC, Weinberger DR, Kleinman JE, Hyde TM. GAD1 alternative transcripts and DNA methylation in human prefrontal cortex and hippocampus in brain development, schizophrenia. Mol Psychiatry 2018; 23:1496-1505. [PMID: 28485403 PMCID: PMC7564279 DOI: 10.1038/mp.2017.105] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 02/20/2017] [Accepted: 04/04/2017] [Indexed: 12/25/2022]
Abstract
Genetic variations and adverse environmental events in utero or shortly after birth can lead to abnormal brain development and increased risk of schizophrenia. γ-Aminobutyric acid (GABA), the major inhibitory neurotransmitter in the mammalian brain, plays a vital role in normal brain development. GABA synthesis is controlled by enzymes derived from two glutamic acid decarboxylase (GAD) genes, GAD1 and GAD2, both of which produce transcript isoforms. While the full-length GAD1 transcript (GAD67) has been implicated in the neuropathology of schizophrenia, the transcript structure of GAD1 in the human brain has not been fully characterized. In this study, with the use of RNA sequencing and PCR technologies, we report the discovery of 10 novel transcripts of GAD1 in the human brain. Expression levels of four novel GAD1 transcripts (8A, 8B, I80 and I86) showed a lifespan trajectory expression pattern that is anticorrelated with the expression of the full-length GAD1 transcript. In addition, methylation levels of two CpG loci within the putative GAD1 promoter were significantly associated with the schizophrenia-risk SNP rs3749034 and with the expression of GAD25 in dorsolateral prefrontal cortex (DLPFC). Moreover, schizophrenia patients who had completed suicide and/or were positive for nicotine exposure had significantly higher full-length GAD1 expression in the DLPFC. Alternative splicing of GAD1 and epigenetic state appear to play roles in the developmental profile of GAD1 expression and may contribute to GABA dysfunction in the PFC and hippocampus of patients with schizophrenia.
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Affiliation(s)
- Ran Tao
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Kasey N. Davis
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Laboratory for Neurodevelopment, Department of Anatomy, Howard University College of Medicine, Washington D.C., USA
| | - Chao Li
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Joo Heon Shin
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Yuan Gao
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA
| | - Andrew E. Jaffe
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Marjorie C. Gondré-Lewis
- Laboratory for Neurodevelopment, Department of Anatomy, Howard University College of Medicine, Washington D.C., USA
| | - Daniel R. Weinberger
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Psychiatry and Behavior Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, USA,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA,McKusick Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Joel E. Kleinman
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Psychiatry and Behavior Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Thomas M. Hyde
- The Lieber Institute for Brain Development, Johns Hopkins University Medical Campus, Baltimore, Maryland, USA,Department of Psychiatry and Behavior Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland, USA,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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7
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Brawek B, Chesters R, Klement D, Müller J, Lerdkrai C, Hermes M, Garaschuk O. A bell-shaped dependence between amyloidosis and GABA accumulation in astrocytes in a mouse model of Alzheimer's disease. Neurobiol Aging 2017; 61:187-197. [PMID: 29107186 DOI: 10.1016/j.neurobiolaging.2017.09.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 09/25/2017] [Accepted: 09/27/2017] [Indexed: 10/18/2022]
Abstract
Functioning at the interface between the nervous and immune systems, in the amyloid-depositing brain, astrocytes become hypertrophic and accumulate around senile plaques. Moreover, hippocampal astrocytes upregulate their γ-aminobutyric acid (GABA) content and enhance tonic inhibition, likely causing local circuit imbalance. It remains, however, unclear whether this effect is hippocampus specific and how it is regulated during disease progression. Here, we studied changes in astrocytic morphology and GABA content in the frontal cortex and dentate gyrus of control and amyloid-depositing mice. Healthy aging was accompanied by a transient increase in astrocytic GABA content at middle age and region-specific alterations of soma size. In contrast, amyloid deposition caused a gradual cortex-accentuated increase in soma size. Importantly, our data uncovered a bell-shaped relationship between the mouse age and astrocytic GABA content in both brain regions. Moreover, in mice carrying an Alzheimer's disease-related mutation in presenilin 1, astrocytes accumulated GABA even in the absence of amyloidosis. These data question the proposed inhibition of astrocytic GABA synthesis as a universal strategy for treating network dysfunction in Alzheimer's disease.
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Affiliation(s)
- Bianca Brawek
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Robert Chesters
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Daniel Klement
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Julia Müller
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Chommanad Lerdkrai
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Marina Hermes
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany
| | - Olga Garaschuk
- Department of Neurophysiology, Institute of Physiology, University of Tübingen, Tübingen, Germany.
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8
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Won YG, Yu HH, Chang YH, Hwang HJ. Lactic Acid Bacterial Starter Culture with Antioxidant andγ-Aminobutyric Acid Biosynthetic Activities Isolated from Flatfish-SikhaeFermentation. J Med Food 2015; 18:1371-9. [DOI: 10.1089/jmf.2015.3458] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Yeong Geol Won
- Department of Food and Biotechnology, Korea University, Sejong, Korea
| | - Hyun-Hee Yu
- Department of Food and Biotechnology, Korea University, Sejong, Korea
| | - Young-Hyo Chang
- Korean Collection for Type Cultures, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Han-Joon Hwang
- Department of Food and Biotechnology, Korea University, Sejong, Korea
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9
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Kirischuk S, Héja L, Kardos J, Billups B. Astrocyte sodium signaling and the regulation of neurotransmission. Glia 2015; 64:1655-66. [DOI: 10.1002/glia.22943] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/28/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Sergei Kirischuk
- University Medical Center of the Johannes Gutenberg University Mainz, Institute of Physiology; Mainz Germany
| | - László Héja
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences; Budapest Hungary
| | - Julianna Kardos
- Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences; Budapest Hungary
| | - Brian Billups
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University; Acton ACT Australia
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10
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Abstract
Gamma-amino butyric acid (GABA) is the major inhibitory neurotransmitter that is known to be synthesized and released from GABAergic neurons in the brain. However, recent studies have shown that not only neurons but also astrocytes contain a considerable amount of GABA that can be released and activate GABA receptors in neighboring neurons. These exciting new findings for glial GABA raise further interesting questions about the source of GABA, its mechanism of release and regulation and the functional role of glial GABA. In this review, we highlight recent studies that identify the presence and release of GABA in glial cells, we show several proposed potential pathways for accumulation and modulation of glial intracellular and extracellular GABA content, and finally we discuss functional roles for glial GABA in the brain.
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Affiliation(s)
- Bo-Eun Yoon
- Department of Nanobiomedical Science, Dankook University Chungnam, South Korea
| | - C Justin Lee
- WCI Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea ; Center for Neural Science and Center for Functional Connectomics, Korea Institute of Science and Technology (KIST) Seoul, South Korea
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11
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Héja L, Nyitrai G, Kékesi O, Dobolyi A, Szabó P, Fiáth R, Ulbert I, Pál-Szenthe B, Palkovits M, Kardos J. Astrocytes convert network excitation to tonic inhibition of neurons. BMC Biol 2012; 10:26. [PMID: 22420899 PMCID: PMC3342137 DOI: 10.1186/1741-7007-10-26] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 03/15/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glutamate and γ-aminobutyric acid (GABA) transporters play important roles in balancing excitatory and inhibitory signals in the brain. Increasing evidence suggest that they may act concertedly to regulate extracellular levels of the neurotransmitters. RESULTS Here we present evidence that glutamate uptake-induced release of GABA from astrocytes has a direct impact on the excitability of pyramidal neurons in the hippocampus. We demonstrate that GABA, synthesized from the polyamine putrescine, is released from astrocytes by the reverse action of glial GABA transporter (GAT) subtypes GAT-2 or GAT-3. GABA release can be prevented by blocking glutamate uptake with the non-transportable inhibitor DHK, confirming that it is the glutamate transporter activity that triggers the reversal of GABA transporters, conceivably by elevating the intracellular Na+ concentration in astrocytes. The released GABA significantly contributes to the tonic inhibition of neurons in a network activity-dependent manner. Blockade of the Glu/GABA exchange mechanism increases the duration of seizure-like events in the low-[Mg2+] in vitro model of epilepsy. Under in vivo conditions the increased GABA release modulates the power of gamma range oscillation in the CA1 region, suggesting that the Glu/GABA exchange mechanism is also functioning in the intact hippocampus under physiological conditions. CONCLUSIONS The results suggest the existence of a novel molecular mechanism by which astrocytes transform glutamatergic excitation into GABAergic inhibition providing an adjustable, in situ negative feedback on the excitability of neurons.
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Affiliation(s)
- László Héja
- Department of Functional Pharmacology, Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Pusztaszeri 59-67, 1025 Budapest, Hungary.
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12
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Masiulis I, Yun S, Eisch AJ. The interesting interplay between interneurons and adult hippocampal neurogenesis. Mol Neurobiol 2011; 44:287-302. [PMID: 21956642 DOI: 10.1007/s12035-011-8207-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 09/07/2011] [Indexed: 10/17/2022]
Abstract
Adult neurogenesis is a unique form of plasticity found in the hippocampus, a brain region key to learning and memory formation. While many external stimuli are known to modulate the generation of new neurons in the hippocampus, little is known about the local circuitry mechanisms that regulate the process of adult neurogenesis. The neurogenic niche in the hippocampus is highly complex and consists of a heterogeneous population of cells including interneurons. Because interneurons are already highly integrated into the hippocampal circuitry, they are in a prime position to influence the proliferation, survival, and maturation of adult-generated cells in the dentate gyrus. Here, we review the current state of our understanding on the interplay between interneurons and adult hippocampal neurogenesis. We focus on activity- and signaling-dependent mechanisms, as well as research on human diseases that could provide better insight into how interneurons in general might add to our comprehension of the regulation and function of adult hippocampal neurogenesis.
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Affiliation(s)
- Irene Masiulis
- UT Southwestern Medical Center, Dallas, TX 75390-9070, USA.
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13
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Abstract
Taste buds consist of at least three principal cell types that have different functions in processing gustatory signals: glial-like (type I) cells, receptor (type II) cells, and presynaptic (type III) cells. Using a combination of Ca2+ imaging, single-cell reverse transcriptase-PCR and immunostaining, we show that GABA is an inhibitory transmitter in mouse taste buds, acting on GABA(A) and GABA(B) receptors to suppress transmitter (ATP) secretion from receptor cells during taste stimulation. Specifically, receptor cells express GABA(A) receptor subunits β2, δ, and π, as well as GABA(B) receptors. In contrast, presynaptic cells express the GABA(A) β3 subunit and only occasionally GABA(B) receptors. In keeping with the distinct expression pattern of GABA receptors in presynaptic cells, we detected no GABAergic suppression of transmitter release from presynaptic cells. We suggest that GABA may serve function(s) in taste buds in addition to synaptic inhibition. Finally, we also defined the source of GABA in taste buds: GABA is synthesized by GAD65 in type I taste cells as well as by GAD67 in presynaptic (type III) taste cells and is stored in both those two cell types. We conclude that GABA is an inhibitory transmitter released during taste stimulation and possibly also during growth and differentiation of taste buds.
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14
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Magnaghi V. GABA and neuroactive steroid interactions in glia: new roles for old players? Curr Neuropharmacol 2010; 5:47-64. [PMID: 18615153 DOI: 10.2174/157015907780077132] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2006] [Revised: 04/24/2006] [Accepted: 07/27/2006] [Indexed: 02/06/2023] Open
Abstract
In recent years it has becoming clear that glial cells of the central and peripheral nervous system play a crucial role from the earliest stages of development throughout adult life. Glial cells are important for neuronal plasticity, axonal conduction and synaptic transmission. In this respect, glial cells are able to produce, uptake and metabolize many factors that are essential for neuronal physiology, including classic neurotransmitters and neuroactive steroids. In particular, neuroactive steroids, which are mainly synthesized by glial cells, are able to modulate some neurotransmitter receptors affecting both glia and neurons. Among the signaling systems that are specialized for neuron-glial communication, we can include neurotransmitter GABA.The main focus of this review is to illustrate the cross-talk between neurons and glial cells in terms of GABA neurotransmission and actions of neuroactive steroids. To this purpose, we will review the presence of the different GABA receptors in the glial cells of the central and peripheral nervous system. Then, we will discuss their modulation by some neuroactive steroids.
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Affiliation(s)
- Valerio Magnaghi
- Department of Endocrinology and Center of Excellence on Neurodegenerative Disease, University of Milan, Italy.
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15
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Ikeda H, Kiritoshi T, Murase K. Effect of excitatory and inhibitory agents and a glial inhibitor on optically-recorded primary-afferent excitation. Mol Pain 2008; 4:39. [PMID: 18817580 PMCID: PMC2565671 DOI: 10.1186/1744-8069-4-39] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2008] [Accepted: 09/26/2008] [Indexed: 11/18/2022] Open
Abstract
The effects of GABA, excitatory amino-acid receptors antagonists and a glial metabolism inhibitor on primary-afferent excitation in the spinal dorsal horn were studied by imaging the presynaptic excitation of high-threshold afferents in cord slices from young rats with a voltage-sensitive dye. Primary afferent fibers and terminals were anterogradely labeled with a voltage-sensitive dye from the dorsal root attached to the spinal cord slice. Single-pulse stimulation of C fiber-activating strength to the dorsal root elicited compound action potential-like optical responses in the superficial dorsal horn. The evoked presynaptic excitation was increased by the GABAA receptor antagonists picrotoxin and bicuculline, by glutamate receptor antagonists D-AP5 and CNQX, and by the glial metabolism inhibitor mono-fluoroacetic acid (MFA). The increase in presynaptic excitation by picrotoxin was inhibited in the presence of D-AP5, CNQX and MFA. Presynaptic modulation in the central terminal of fine primary afferents by excitatory and inhibitory amino acids may represent a mechanism that regulates the transmission of pain.
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Affiliation(s)
- Hiroshi Ikeda
- Department of Human and Artificial Intelligence Systems, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507, Japan.
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16
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Angulo MC, Le Meur K, Kozlov AS, Charpak S, Audinat E. GABA, a forgotten gliotransmitter. Prog Neurobiol 2008; 86:297-303. [PMID: 18786601 DOI: 10.1016/j.pneurobio.2008.08.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 05/30/2008] [Accepted: 08/12/2008] [Indexed: 01/27/2023]
Abstract
The amino acid gamma-aminobutiric acid (GABA) is a major inhibitory transmitter in the vertebrate central nervous system (CNS) where it can be released by neurons and by glial cells. Neuronal GABAergic signaling is well characterized: the mechanisms of GABA release, the receptors it targets and the functional consequences of their activation have been extensively studied. In contrast, the corresponding features of glial GABAergic signaling have attracted less attention. In this review, we first discuss evidence from the literature for GABA accumulation, production and release by glial cells. We then review the results of recent experiments that point toward functional roles of GABA as a "gliotransmitter".
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Affiliation(s)
- María Cecilia Angulo
- Inserm U603, Paris, France; CNRS UMR 8154, Paris, France; Université Paris Descartes, Paris, France
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Lewitus GM, Zhu J, Xiong H, Hallworth R, Kipnis J. CD4+CD25- effector T-cells inhibit hippocampal long-term potentiation in vitro. Eur J Neurosci 2007; 26:1399-406. [PMID: 17880384 DOI: 10.1111/j.1460-9568.2007.05788.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
During neuroinflammation T-cells invade the CNS, and may lead to the development and progression of several pathologies, of which multiple sclerosis is the most common. In these pathologies neuroinflammation is often associated with cognitive dysfunction. Using mouse hippocampal slices, we show here that CD4(+)CD25(-) T-cells inhibit long-term potentiation (LTP) induced by high-frequency stimulation. The T-cell-mediated inhibition of LTP can be prevented by blockade of gamma-aminobutyric acid (GABA)(A) receptors. These findings provide additional insight into the multiple functions of T-cells in CNS pathologies.
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Affiliation(s)
- Gil M Lewitus
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
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Shin JW, Kim DG, Lee YW, Lee HS, Shin KS, Choi CS, Kwon GS. Isolation and Characterization of Lactobacillus brevis AML15 Producing γ-Aminobutyric acid. ACTA ACUST UNITED AC 2007. [DOI: 10.5352/jls.2007.17.7.970] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Won YJ, Yoo JY, Lee JH, Hwang SJ, Kim D, Hong HN. Erythropoietin is neuroprotective on GABAergic neurons against kainic acid-excitotoxicity in the rat spinal cell cultures. Brain Res 2007; 1154:31-9. [PMID: 17493599 DOI: 10.1016/j.brainres.2007.04.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 03/20/2007] [Accepted: 04/03/2007] [Indexed: 02/07/2023]
Abstract
The aim of this study was to investigate whether erythropoietin (EPO) protect the spinal GABAergic neurons against kainic acid (KA)-excitotoxic damage in rat spinal cord cell cultures. We performed immunohistochemical staining and Western blotting of glutamate decarboxylase 67 (GAD67), one isoform of GABA-producing enzyme, which was considered to have involved in nonsynaptic functions, such as energy metabolism or trophic support. T exposure to KA significantly reduced the intensity of GAD67 expression in the GABAergic neurons and whole cell lysate, indicating that the excitotoxic damage on the GABAergic neurons may lead to reduction of the GAD67 production following KA-exposure. We found that post-treatment of EPO for 48 h after KA-injury remarkably enhanced the expression level of GAD67 and erythropoietin receptors (EpoR), which were deteriorated by KA. Our confocal images clearly demonstrated a remarkably enhanced expression of EpoR on the surface of the GABAergic neurons by post-treated EPO after KA-damage. This result suggests that the neuroprotective effect of post-treated EPO on the GABAergic neurons can be related to the EPO-mediated EpoR upregulation following KA-excitotoxicity. We observed that the post-applied EPO clearly increased expression of tyrosine Janus kinase 2 (JAK2), which is known to be the first step of EpoR-stimulation. In conclusion, the post-treated EPO is a potent protector of the spinal GABAergic neurons against KA-excitotoxicity and regulates production of GAD67 for the multiple trophic roles after KA-induced disturbance. We suggested that the protective effect of post-treated EPO on the GABAergic neurons is mediated by signal transduction involving EpoR-dependent JAK2 pathway.
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Affiliation(s)
- You Jin Won
- Department of Anatomy and Cell Biology, University of Ulsan College of Medicine, 388-1 Pungnap-dong, Songpa-gu, Seoul 138-736, South Korea
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Magnaghi V, Ballabio M, Consoli A, Lambert JJ, Roglio I, Melcangi RC. GABA receptor-mediated effects in the peripheral nervous system: A cross-interaction with neuroactive steroids. J Mol Neurosci 2006; 28:89-102. [PMID: 16632878 DOI: 10.1385/jmn:28:1:89] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 11/30/1999] [Accepted: 08/18/2005] [Indexed: 12/18/2022]
Abstract
Gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the adult mammalian central nervous system (CNS), exerts its action via an interaction with specific receptors (e.g., GABAA and GABAB). These receptors are expressed not only in neurons but also on glial cells of the CNS, which might represent a target for the allosteric action of neuroactive steroids. Herein, we have demonstrated first that in the peripheral nervous system (PNS), the sciatic nerve and myelin-producing Schwann cells express both GABAA and GABAB receptors. Specific ligands, muscimol and baclofen, respectively, control Schwann-cell proliferation and expression of some specific myelin proteins (i.e., glycoprotein P0 and peripheral myelin protein 22 [PMP22]). Moreover, the progesterone (P) metabolite allopregnanolone, acting via the GABAA receptor, can influence PMP22 synthesis. In addition, we demonstrate that P, dihydroprogesterone, and allopregnanolone influence the expression of GABAB subunits in Schwann cells. The results suggest, at least in the myelinating cells of the PNS, a cross-interaction within the GABAergic receptor system, via GABAA and GABAB receptors and neuroactive steroids.
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Affiliation(s)
- Valerio Magnaghi
- Department of Endocrinology and Center of Excellence on Neurodegenerative Diseases, University of Milan, 20133 Milan, Italy.
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Kozlov AS, Angulo MC, Audinat E, Charpak S. Target cell-specific modulation of neuronal activity by astrocytes. Proc Natl Acad Sci U S A 2006; 103:10058-63. [PMID: 16782808 PMCID: PMC1502505 DOI: 10.1073/pnas.0603741103] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interaction between astrocytes and neurons enriches the behavior of brain circuits. By releasing glutamate and ATP, astrocytes can directly excite neurons and modulate synaptic transmission. In the rat olfactory bulb, we demonstrate that the release of GABA by astrocytes causes long-lasting and synchronous inhibition of mitral and granule cells. In addition, astrocytes release glutamate, leading to a selective activation of granule-cell NMDA receptors. Thus, by releasing excitatory and inhibitory neurotransmitters, astrocytes exert a complex modulatory control on the olfactory network.
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Affiliation(s)
- A. S. Kozlov
- Laboratory of Neurophysiology, Institut National de la Santé et de la Recherche Médicale U603 and Centre National de la Recherche Scientifique FRE2500, Ecole Supérieure de Physique et de Chimie Industrielles, and Université Paris Descartes, 75006 Paris, France
- To whom correspondence should be sent at the present address:
Laboratory of Sensory Neuroscience, The Rockefeller University, 1230 York Avenue, New York, NY 10021. E-mail:
| | - M. C. Angulo
- Laboratory of Neurophysiology, Institut National de la Santé et de la Recherche Médicale U603 and Centre National de la Recherche Scientifique FRE2500, Ecole Supérieure de Physique et de Chimie Industrielles, and Université Paris Descartes, 75006 Paris, France
| | - E. Audinat
- Laboratory of Neurophysiology, Institut National de la Santé et de la Recherche Médicale U603 and Centre National de la Recherche Scientifique FRE2500, Ecole Supérieure de Physique et de Chimie Industrielles, and Université Paris Descartes, 75006 Paris, France
| | - S. Charpak
- Laboratory of Neurophysiology, Institut National de la Santé et de la Recherche Médicale U603 and Centre National de la Recherche Scientifique FRE2500, Ecole Supérieure de Physique et de Chimie Industrielles, and Université Paris Descartes, 75006 Paris, France
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Seidenfaden R, Desoeuvre A, Bosio A, Virard I, Cremer H. Glial conversion of SVZ-derived committed neuronal precursors after ectopic grafting into the adult brain. Mol Cell Neurosci 2006; 32:187-98. [PMID: 16730456 DOI: 10.1016/j.mcn.2006.04.003] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 03/27/2006] [Accepted: 04/06/2006] [Indexed: 12/23/2022] Open
Abstract
In the adult mouse forebrain, large numbers of neuronal precursors, destined to become GABA- and dopamine-producing interneurons of the olfactory bulb (OB), are generated in the subventricular zone (SVZ). Although this neurogenic system represents a potential reservoir of stem and progenitor cells for brain repair approaches, information about the survival and differentiation of SVZ-derived cells in ectopic brain regions is still fragmentary. We show here that ectopic grafting of SVZ tissue gave rise to two morphologically distinguishable cell types displaying oligodendrocytic or astrocytic characteristics. Since SVZ tissue contains neuronal and glial progenitors, we used magnetic cell sorting to deplete A2B5+ glial progenitors from the dissociated SVZ and to positively select cells that express PSA-NCAM. This procedure allowed the purification of neuronal precursors expressing TUJ1, DCX and GAD65/67. Transplantation of these cells led again to the generation of the same two glial cell types, showing that committed interneuron precursors undergo glial differentiation outside their normal environment.
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Affiliation(s)
- Ralph Seidenfaden
- Institut de Biologie du Développement de Marseille, CNRS, Université de la Méditeranée, Campus de Luminy-case 907, 13288 Marseille cedex 9, France.
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McKenna MC, Sonnewald U. GABA alters the metabolic fate of [U-13C]glutamate in cultured cortical astrocytes. J Neurosci Res 2004; 79:81-7. [PMID: 15593283 DOI: 10.1002/jnr.20309] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The effect of gamma-aminobutyric acid (GABA) on glutamate metabolism was studied by (13)C-nuclear magnetic resonance (NMR) spectroscopy. Cerebral cortical astrocytes were incubated with 0.5 mM [U-(13)C]glutamate and 5 mM glucose in the presence or absence of 0.2 mM GABA for 2 hr. (13)C-labeled glutamate, glutamine, and aspartate were observed in cell extracts, and (13)C-labeled glutamine and lactate were present in the media. Both uniformly labeled glutamate and [1,2,3-(13)C]glutamate derived from the tricarboxylic acid (TCA) cycle were present in the cells. The consumption of [U-(13)C]glutamate and glucose was unchanged in the presence of GABA; however, the formation of [U-(13)C]lactate and [U-(13)C]aspartate from metabolism of [U-(13)C]glutamate was increased in cells incubated with GABA. The total concentration of aspartate was increased to the same extent as the (13)C-labeled aspartate, suggesting increased entry of [U-(13)C]glutamate into the TCA cycle to allow for the transamination of GABA. Although the concentrations of unlabeled glucose and lactate in the media were unchanged in the presence of GABA, the concentration of alanine was decreased, indicating that there was decreased transamination of the unlabeled pyruvate from glucose metabolism. The amount of [U-(13)C]glutamate converted to [U-(13)C]glutamine and [U-(13)C]lactate was increased in the presence of GABA. However, since the overall consumption of [U-(13)C]glutamate was not different, it can be concluded that the amount of [U-(13)C]glutamate used for energy was decreased. This suggests that exogenous GABA could substitute for glutamate as an energy source for astrocytes. The results indicate that the presence of GABA influences the metabolic fate of both glutamate and glucose in astrocytes, suggesting that fluctuations in the concentration of GABA in normal and pathological conditions can alter the compartmentation of glial metabolism in brain.
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Affiliation(s)
- Mary C McKenna
- Department of Pediatrics, University of Maryland School of Medicine, 655 W. Baltimore Street., Room 10-031, Baltimore, MD 21201, USA.
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