Alphaxalone reveals GABAA receptor-mediated inhibition in guinea-pig ileum.
Contractions of the transmurally stimulated guinea-pig ileum were not affected by 10 microM bicuculline, a competitive GABAA receptor antagonist. The GABAA potentiator alphaxalone depressed the responses to 2 and 20 Hz stimulation by 20% and 40%, respectively, but had no effect on 0.2 Hz responses. The depressions were prevented by 10 microM bicuculline. This suggests that endogenous activation of GABAA receptors during transmural stimulation was normally subthreshold but, when pharmacologically potentiated, inhibitory effects were seen.
Healing
C
C
Department of Pharmacology, School of Pharmacy, University of London, UK.
Hilton
T
T
Simmonds
M
M
D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007537:Isometric Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011277:Pregnanediones / Q000494:pharmacology*; D011963:Receptors, GABA-A / Q000502:physiology*
D000777:Anesthetics; D011277:Pregnanediones; D011963:Receptors, GABA-A; C006477:alphaxalone; D001640:Bicuculline