gamma-Aminobutyric acid receptor channels in adrenal chromaffin cells: a patch-clamp study.
We have studied membrane channels activated by gamma-aminobutyric acid (GABA) in adrenal medullary chromaffin cells by using patch-clamp techniques. These channels share many properties with GABA-receptor channels in the central nervous system. They are chloride-selective, blocked by the GABA antagonist bicuculline, and reversibly desensitized at high GABA concentrations. The dose-response curve has a slope of 2 in the Hill plot, indicating a bimolecular binding reaction of GABA to the receptor. Single-channel currents display multiple conductance states as do glycine-activated chloride channels in mouse spinal neurons. Gating properties of GABA-activated channels, as described by a sequential model for agonist-activated channels, are similar to gating properties in central neurons. GABA-induced currents are potentiated by diazepam, indicating that anxiolytic drugs like the benzodiazepines might be involved in the regulation of anxiety states in the peripheral nervous system.
Bormann
J
J
Clapham
D E
DE
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002712:Chlorides / Q000378:metabolism*; D002838:Chromaffin System / Q000187:drug effects / Q000502:physiology*; D003975:Diazepam / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D002712:Chlorides; D007473:Ion Channels; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid; D003975:Diazepam