Abstract
Neuronal cell lines provide a source of pure populations of neurons and allow the properties of many neurotransmitter receptors to be studied. However, none of these cells have been reported to express functional gamma-aminobutyric acid (GABA)A receptors. Indeed, there have been no reports of cell lines expressing functional amino acid receptors. Using biochemical and electrophysiological techniques, we have identified a neuronal cell line expressing functional GABAA receptors. Membranes from immortalized hypothalamic (GT1-7) neurons bound [3H]muscimol but not [3H]flunitrazepam. GABA-activated chloride currents, recorded from GT1-7 cells, were blocked by bicuculline and Zn2+ but were insensitive to diazepam. These results suggest that GABAA receptors on GT1-7 cells lack gamma subunits. The neurosteroid 5 alpha-pregnan-3 alpha-ol-20-one and pentobarbital both modulated GABAA receptors in these cells. Polymerase chain reaction analysis of the cells revealed the presence of mRNAs encoding alpha 1, beta 1, and beta 3 polypeptides. GT1-7 cells provide a useful model system for studying the regulation of GABAA receptor polypeptide expression.
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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Anesthetics / pharmacology
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Animals
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Barbiturates / pharmacology
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Base Sequence
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Bicuculline / pharmacology
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Cell Line, Transformed
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Cell Membrane / metabolism
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Cell Membrane / physiology
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Chloride Channels
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Diazepam / pharmacology
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Electrophysiology
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Flunitrazepam / pharmacology
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GABA Antagonists
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Gene Expression Regulation / genetics
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Gene Expression Regulation / physiology
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Hypothalamus / pathology
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Hypothalamus / physiology
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Hypothalamus / ultrastructure*
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Membrane Proteins / physiology
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Mice
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Molecular Sequence Data
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Muscimol / metabolism
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Neurons / pathology
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Neurons / ultrastructure*
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Peptides / genetics
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Polymerase Chain Reaction
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RNA, Messenger / analysis
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RNA, Messenger / genetics
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Receptors, GABA-A / classification
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Receptors, GABA-A / genetics
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Receptors, GABA-A / physiology*
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Sensitivity and Specificity
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Steroids / pharmacology
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Tritium
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Tumor Cells, Cultured
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Zinc / pharmacology
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gamma-Aminobutyric Acid / pharmacology
Substances
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Anesthetics
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Barbiturates
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Chloride Channels
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GABA Antagonists
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Membrane Proteins
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Peptides
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RNA, Messenger
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Receptors, GABA-A
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Steroids
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Tritium
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Muscimol
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gamma-Aminobutyric Acid
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Flunitrazepam
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Zinc
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Diazepam
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Bicuculline