Abstract
Externally applied gamma-aminobutyric acid (GABA) quickly and reversibly reduces by 60% voltage activated Ca2+ currents in chick dorsal root ganglion cells. This action is antagonized by depolarization, with characteristic time and voltage requirements. Intracellular perfusion with guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) or guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) mimicks and blocks the GABA effect, respectively. A 3-state model describing the reactions involved is proposed.
MeSH terms
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Animals
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Calcium Channels / drug effects
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Calcium Channels / metabolism*
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Chick Embryo
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Ganglia, Spinal / cytology
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Ganglia, Spinal / drug effects
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Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
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Guanosine Diphosphate / analogs & derivatives
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Guanosine Diphosphate / pharmacology
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Membrane Potentials / drug effects
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Neurons, Afferent / drug effects
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Neurons, Afferent / metabolism*
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Thionucleotides / pharmacology
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gamma-Aminobutyric Acid / pharmacology*
Substances
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Calcium Channels
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Thionucleotides
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Guanosine Diphosphate
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Guanosine 5'-O-(3-Thiotriphosphate)
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gamma-Aminobutyric Acid
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guanosine 5'-O-(2-thiodiphosphate)