| Literature DB >> 2888123 |
H Callachan, G A Cottrell, N Y Hather, J J Lambert, J M Nooney, J A Peters.
Abstract
The naturally occurring progesterone metabolites 5 beta-pregnan-3 alpha-ol-20-one and 5 beta-pregnane-3,20-dione reversibly enhance membrane currents elicited by locally applied GABA in bovine adrenomedullary chromaffin cells. Such potentiation was not influenced by the benzodiazepine antagonist Ro 15-1788. At concentrations in excess of those necessary to evoke potentiation of GABA currents, 5 beta-pregnan-3 alpha-ol-20-one and 5 beta-pregane-3,20-dione directly activated a membrane conductance. The resulting currents were potentiated by phenobarbitone and diazepam, and abolished by the GABAA-receptor antagonist, bicuculline. On outside-out membrane patches, 5 beta-pregnan-3 alpha-ol-20-one and 5 beta-pregnane-3,20-dione activated single channel currents of similar amplitude to those evoked by GABA. The results suggest that certain naturally occurring steroids potentiate the actions of GABA and, additionally, directly activate the GABAA receptor.Entities:
Mesh：
Substances：
Year: 1987 PMID： 2888123 DOI： 10.1098/rspb.1987.0049
Source DB: PubMed Journal: Proc R Soc Lond B Biol Sci ISSN： 0950-1193