NEURAL INHIBITION IN THE RAT LOWER ESOPHAGEAL SPHINCTER - ROLE OF BETA-3-ADRENOCEPTOR ACTIVATION

1. Electrical field stimulation (EPS) of the lower esophageal sphincte r produced tetrodoxtoin-sensitive relaxant responses. 2. The relaxant responses were not significantly affected by propranolol but were atte nuated by 6-hydroxydopamine and cyanopindolol, indicating beta(3)-adre noceptor activation. 3. The relexant responses were significantly redu ced in tissues previously exposed to BRL 37344, a beta(3)-adrenoceptor agonist. 4. It was concluded that EFS-induced relaxation was adrenerg ic in origin and was mediated by beta(3)-adrenoceptors. (C) 1998 Elsev ier Science Inc.