Specific [3H]gamma-aminobutyric acid binding to vestibular membranes of the chick inner ear.
To support a postulated neurotransmitter character of gamma-aminobutyric acid (GABA) in the vertebrate vestibule, [3H]GABA binding was measured in a crude membrane preparation of chick inner ear ampullary cristae. In the absence of divalent cations bound [3H]GABA was displaced by unlabeled GABA, muscimol or bicuculline, but it was not displaced by (+/-)-baclofen. A single population of [3H]GABA binding sites with an equilibrium constant of 19.4 nM and a maximum binding capacity of 0.58 pmol/mg protein was found. These results suggest the possible existence of a synaptic GABAA receptor in the chick inner ear membranes and sustain the neurotransmitter role of GABA in the chick vestibule.
Meza
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González-Viveros
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Ruiz
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D000818:Animals; D001418:Baclofen / Q000378:metabolism; D001640:Bicuculline / Q000378:metabolism; D001667:Binding, Competitive; D002645:Chickens / Q000378:metabolism*; D008297:Male; D009118:Muscimol / Q000378:metabolism; D011963:Receptors, GABA-A / Q000032:analysis*; D013347:Subcellular Fractions / Q000378:metabolism; D014722:Vestibule, Labyrinth / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D011963:Receptors, GABA-A; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; D001418:Baclofen; D001640:Bicuculline