picrotoxinin and bicuculline-methochloride

Rhythmic neurally mediated spontaneous relaxations of the longitudinal muscle in the isolated ileum of the guinea pig are modified by GABA antagonism. Bicuculline methochloride, a GABAA-receptor antagonist, and picrotoxinin, a Cl--ionophore blocker, as well as GABA desensitization reduced or most often abolished these naturally occurring periodic spontaneous relaxations, indicating a physiological involvement of GABA in the control of intestinal motility. The possible mechanism whereby GABA may induce such relaxations is discussed in relation to GABA actions in the enteric nervous system where GABA is a neurotransmitter.

Topics: Animals; Bicuculline; Female; gamma-Aminobutyric Acid; Gastrointestinal Motility; Guinea Pigs; Ileum; Male; Muscle, Smooth; Myenteric Plexus; Picrotoxin; Sesterterpenes; Tachyphylaxis