The role of adrenoceptors in the mechanism of reserpine-induced stimulation of gastric acid secretion in the rat

Abstract

Abstract The role of α- and β-adrenoceptors in the mechanism of reserpine-induced stimulation of gastric acid secretion in the rat has been examined. After 6 h reserpine (0.1 mg kg−1 i.p.) significantly stimulated acid secretion relative to control values (176 ± 4 vs 60 ± 3 μmol, mean ± s.e.m., n = 10, P < 0.001). Neither coeliac ganglionectomy nor propranolol (5–15 mg kg−1) influenced this action. Vagotomy prevented acid stimulation by reserpine and was associated with H+ output similar to that of vagotomy controls (13 ± 1 vs 14 ± 1 μmol, mean ± s.e.m., n = 10). Dose-dependent inhibition of the reserpine-induced acid secretion was produced by phenoxybenzamine or phentolamine; an inhibition similar to that achieved by vagotomy was noted with the 15 mg kg−1 dose (13 ± 1 and 15 ± 1 μmol, respectively, vs 176 ± 4 μmol, mean ± s.e.m., n = 10, P < 0.001). The similarity in action between vagotomy and large doses of phenoxybenzamine or phentolamine suggests that, in the rat, vagal α-adrenoceptor stimulation is directly involved in the mechanism of reserpine-induced stimulation of gastric acid secretion.