Cerebroventricular bombesin inhibits gastric acid secretion in dogs

Bolus injections of bombesin into a lateral cerebral ventricle of conscious beagle dogs inhibited pentagastrin-stimulated gastric acid secretion from both the innervated stomach (gastric fistula) and the vagally denervated Heidenhain pouch in a dose dependent manner. Bombesin (300 ng/kg), injected into the lateral ventricle, inhibited acid secretion from the gastric fistula and Heidenhain pouch by 66% +/- 5% and 93% +/- 4%, respectively. Central administration of bombesin also suppressed acid secretion in response to a meal by 52% +/- 15%; postprandial gastrin response was not affected. By contrast, intravenous infusion of bombesin stimulated both gastrin release and acid secretion without affecting the acid response to a submaximal dose of pentagastrin. The opposing effects of central and peripheral bombesin on acid secretion indicate that the gastric response to intracerebrally administered bombesin is mediated by the central nervous system. Furthermore, the inhibitory action of bombesin injected into the lateral cerebral ventricle is independent of the vagus and is not mediated by the inhibition of gastrin release. These observations demonstrate that bombesin-like peptides may act centrally to alter gastric secretion.