Inhibition of gastric emptying by bombesin-like peptides is dependent uponcholecystokinin-A receptor activation

The amphibian peptide bombesin (BN) and the related mammalian peptides gast rin-releasing peptide (GRP) and neuromedin B (NMB) inhibit gastric emptying in rats. Exogenous administration of BN stimulates the release of cholecys tokinin (CCK), a gastrointestinal peptide that also potently inhibits gastr ic emptying. To determine whether the inhibition of gastric emptying by BN- like peptides is mediated by a CCK-dependent mechanism, we examined the abi lity of the CCK-A receptor antagonist, devazepide, to block the inhibition of saline gastric emptying produced by BN, GRP18-27 and NMB. Using the same dosages as in the gastric emptying experiment, we also evaluated the effec t of devazepide on feeding suppression produced by systemically administere d BN. Our results showed that devazepide completely blocked the suppression of gastric emptying produced by BN, GRP18-27 and NMB but had no effect on BN-induced suppression of food intake. These results suggest that BN-like p eptides inhibit gastric emptying through an indirect mechanism that is depe ndent upon CCK-A receptor activation. In contrast, the suppression of food intake by BN, in this experimental paradigm, is independent of CCK-A recept ors. (C) 1999 Elsevier Science B.V. All rights reserved.