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Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA

Glutamate and GABA are the quantitatively major neurotransmitters in the brain mediating excitatory and inhibitory signaling, respectively. These amino acids are metabolically interrelated and at the same time they are tightly coupled to the intermediary metabolism including energy homeostasis. Astr...

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Autores principales: Schousboe, Arne, Bak, Lasse K., Waagepetersen, Helle S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3744088/
https://www.ncbi.nlm.nih.gov/pubmed/23966981
http://dx.doi.org/10.3389/fendo.2013.00102
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author Schousboe, Arne
Bak, Lasse K.
Waagepetersen, Helle S.
author_facet Schousboe, Arne
Bak, Lasse K.
Waagepetersen, Helle S.
author_sort Schousboe, Arne
collection PubMed
description Glutamate and GABA are the quantitatively major neurotransmitters in the brain mediating excitatory and inhibitory signaling, respectively. These amino acids are metabolically interrelated and at the same time they are tightly coupled to the intermediary metabolism including energy homeostasis. Astrocytes play a pivotal role in the maintenance of the neurotransmitter pools of glutamate and GABA since only these cells express pyruvate carboxylase, the enzyme required for de novo synthesis of the two amino acids. Such de novo synthesis is obligatory to compensate for catabolism of glutamate and GABA related to oxidative metabolism when the amino acids are used as energy substrates. This, in turn, is influenced by the extent to which the cycling of the amino acids between neurons and astrocytes may occur. This cycling is brought about by the glutamate/GABA – glutamine cycle the operation of which involves the enzymes glutamine synthetase (GS) and phosphate-activated glutaminase together with the plasma membrane transporters for glutamate, GABA, and glutamine. The distribution of these proteins between neurons and astrocytes determines the efficacy of the cycle and it is of particular importance that GS is exclusively expressed in astrocytes. It should be kept in mind that the operation of the cycle is associated with movement of ammonia nitrogen between the two cell types and different mechanisms which can mediate this have been proposed. This review is intended to delineate the above mentioned processes and to discuss quantitatively their relative importance in the homeostatic mechanisms responsible for the maintenance of optimal conditions for the respective neurotransmission processes to operate.
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spelling pubmed-37440882013-08-21 Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA Schousboe, Arne Bak, Lasse K. Waagepetersen, Helle S. Front Endocrinol (Lausanne) Endocrinology Glutamate and GABA are the quantitatively major neurotransmitters in the brain mediating excitatory and inhibitory signaling, respectively. These amino acids are metabolically interrelated and at the same time they are tightly coupled to the intermediary metabolism including energy homeostasis. Astrocytes play a pivotal role in the maintenance of the neurotransmitter pools of glutamate and GABA since only these cells express pyruvate carboxylase, the enzyme required for de novo synthesis of the two amino acids. Such de novo synthesis is obligatory to compensate for catabolism of glutamate and GABA related to oxidative metabolism when the amino acids are used as energy substrates. This, in turn, is influenced by the extent to which the cycling of the amino acids between neurons and astrocytes may occur. This cycling is brought about by the glutamate/GABA – glutamine cycle the operation of which involves the enzymes glutamine synthetase (GS) and phosphate-activated glutaminase together with the plasma membrane transporters for glutamate, GABA, and glutamine. The distribution of these proteins between neurons and astrocytes determines the efficacy of the cycle and it is of particular importance that GS is exclusively expressed in astrocytes. It should be kept in mind that the operation of the cycle is associated with movement of ammonia nitrogen between the two cell types and different mechanisms which can mediate this have been proposed. This review is intended to delineate the above mentioned processes and to discuss quantitatively their relative importance in the homeostatic mechanisms responsible for the maintenance of optimal conditions for the respective neurotransmission processes to operate. Frontiers Media S.A. 2013-08-15 /pmc/articles/PMC3744088/ /pubmed/23966981 http://dx.doi.org/10.3389/fendo.2013.00102 Text en Copyright © 2013 Schousboe, Bak and Waagepetersen. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Endocrinology
Schousboe, Arne
Bak, Lasse K.
Waagepetersen, Helle S.
Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA
title Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA
title_full Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA
title_fullStr Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA
title_full_unstemmed Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA
title_short Astrocytic Control of Biosynthesis and Turnover of the Neurotransmitters Glutamate and GABA
title_sort astrocytic control of biosynthesis and turnover of the neurotransmitters glutamate and gaba
topic Endocrinology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3744088/
https://www.ncbi.nlm.nih.gov/pubmed/23966981
http://dx.doi.org/10.3389/fendo.2013.00102
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