Changes in gastric secretion after intracerebroventricular infusion of bombesin in dogs

Synthetic bombesin (BBS) was infused intracerebroventricularly in 14 mongrel dogs, to study the effects of the peptide on gastric secretion and on gastrin and neurotensin levels. The infusion was performed with a specific apparatus, and gastric fluid was collected with a Pavlov pouch. BBS was given in two series of experiments: as a bolus intracerebroventricular injection of 308.6 pmol/kg and as a continuous intracerebroventricular infusion at a rate of 617.3 pmol/kg/h for 30 min. The bolus injection caused a very significant decrease of gastric fluid volume, a significant decrease of HCl output, and a significant increase of its pH, while serum immunoreactive gastrin increased significantly. The continuous infusion of BBS caused similar changes in gastric secretion. The plasma neurotensin levels did not change. In conclusion, the intracerebroventricular administration of BBS increases the serum gastrin levels, decreases the volume and HCl content of gastric fluid, and increases its pH.