Abstract
Effects of a new β2-adrenoceptive agonist, BD 40A on gastric acid secretion and gastrointestinal motility were studied in comparison with those of isoproterenol, hexoprenaline and cimetidine. BD 40A (0.3 and 1 μg/kg i.v.) inhibited dose-dependently gastric acid secretion produced by continuous i.v. infusion of tetragastrin (8 μg/kg-hr), whereas acid secretion in response to histamine infusion (160 μg/kg-hr) was resistant to the inhibitory action of BD 40A in pentobarbital anesthetized dogs with gastric pouches. Cimetidine (0.3 and 1 mg/kg) blocked acid secretion induced by either tetragastrin or histamine. When intraduodenally administered to pylorus-ligated rats in a dose of 1 mg/kg, BD 40A and hexoprenaline produced a reduction in acid output. Both drugs (1 μg/kg i.v.) decreased the amplitude of gastric, duodenal and ileal motility measured by the balloon method in anesthetized dogs. The inhibitory effects of BD 40A on acid secretion induced by tetragastrin and on spontaneous motility of the gastrointestinal tract were antagonized by 1 mg/kg of propranolol. These pharmacological properties of BD 40A were qualitatively similar to those of isoproterenol and may be ascribable to the activation of β-adrenergic receptors in the gastrointestinal tissue.
