Inhibition of gastrin‐ and histamine‐stimulated gastric acid secretion by gastrin and cholecystokinin antagonists in the rat

The gastric acid inhibitory activities of a peptide-like gastrin receptor antagonist, Boc-beta Ala-Trp-Leu-Asp-O(CH2)2-Ph-4-F (CH-486), a nonpeptide gastrin/CCK-B antagonist (L-365,260), and a CCK-A antagonist (L-364,718), were investigated in the gastric lumen-perfused anaesthetized rat. A single i.v. injection of CH-486, 100 mumol/kg, reduced acid secretion stimulated by pentagastrin, 15 micrograms kg/h, to unstimulated levels, with no recovery within 50 min. Histamine-, 0.1 mumol kg/min, and carbamylcholine-, 0.1 mg kg/h, stimulated acid secretion were also reduced to unstimulated levels by CH-486, 100 mumol/kg, although with these latter two stimulants the inhibition was transient. L-365,260 and L-364,718, 10 mumol/kg, significantly inhibited both pentagastrin- and histamine-stimulated acid secretion, the latter again transiently. We conclude that the non-selective nature of the gastric acid inhibitory activity of gastrin antagonists might allow novel approaches to control gastric acid secretion in peptic ulcer disease.