DIFFERENT EFFECTS OF CCK ANTAGONISTS ON GASTRIC-ACID RESPONSE TO CCK AND PENTAGASTRIN

The role of CCK receptor subtypes in peptide-stimulated acid secretion was assessed in six unanesthetized rats. The CCK-stimulated acid secretion was not blocked by L-365,260, a CCK(B)/gastrin receptor antagonist, and was significantly increased by devazepide, a CCK(A) receptor antagonist, given alone or together with L-365,260. L-365,260, but not devazepide, blocked pentagastrin-stimulated acid secretion, and, when given together, devazepide abolished the effect of L-365,260. We conclude: 1) pentagastrin stimulates acid secretion through a gastrin-type receptor, but CCK may not, and 2) pentagastrin and CCK can stimulate acid secretion despite simultaneous blockade of CCK(B)/gastrin and CCK(A) receptors.