gastrins and 5-aminovaleric-acid

In order to investigate the role of peripheral GABA-B receptors, the effects of the putative GABA-B agonist baclofen on immunoreactive gastrin release from an isolated vascularly perfused rat stomach preparation were examined. The vascular infusion of baclofen at graded concentrations induced a dose-dependent increase in gastrin release; this was unaffected by the GABA-B antagonist delta-aminovaleric acid, but was fully prevented by the selective GABA-A antagonist bicuculline as well as by atropine or tetrodotoxin. These results suggest that the stimulant effects of baclofen are mediated by nervous cholinergic structures associated with GABA-A receptors, and indicate that this GABA-B agonist must be regarded as a partial agonist of peripheral GABA-A receptors.

Topics: Amino Acids; Amino Acids, Neutral; Animals; Atropine; Baclofen; Bicuculline; Gastric Mucosa; Gastrins; In Vitro Techniques; Male; Radioimmunoassay; Rats; Rats, Inbred Strains; Receptors, GABA-A; Tetrodotoxin