Abstract
The synaptic action of gamma-aminobutyric acid (GABA) is terminated by high affinity, Na(+)-dependent transport processes in both neurons and glia. We have isolated a novel GABA transporter cDNA, GAT-B, which encodes a high affinity (Km = 2.3 microM), Na(+)- and Cl(-)-dependent GABA transport protein that is potently blocked by beta-alanine, a compound generally considered a selective inhibitor of glial transport. However, in situ hybridization studies indicate that GAT-B mRNA is expressed predominantly within neurons. These data indicate that the neuronal-glial distinction of GABA transporters based on inhibitor sensitivities must be reconsidered and suggest a greater diversity of GABA transporters than has been predicted by previous pharmacologic studies.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Base Sequence
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Brain Chemistry*
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Carrier Proteins*
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Chlorides / pharmacology
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DNA / chemistry
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DNA / genetics
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GABA Plasma Membrane Transport Proteins
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Gene Expression*
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Humans
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Male
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Membrane Proteins*
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Membrane Transport Proteins*
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Molecular Sequence Data
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Nerve Tissue Proteins / analysis
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Nerve Tissue Proteins / genetics*
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Neuroglia / chemistry
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Neurons / chemistry*
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Nucleic Acid Hybridization
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Organic Anion Transporters*
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RNA, Messenger / analysis
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Rats
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Rats, Inbred Strains
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Sodium / pharmacology
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Tissue Distribution
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beta-Alanine / pharmacology*
Substances
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Carrier Proteins
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Chlorides
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GABA Plasma Membrane Transport Proteins
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Membrane Proteins
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Membrane Transport Proteins
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Nerve Tissue Proteins
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Organic Anion Transporters
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RNA, Messenger
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beta-Alanine
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DNA
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Sodium