Effect of Metiamide, a Histamine Antagonist of H2-Receptors, on Acid Secretion of Isolated Canine Stomach Perfused with Homologous Blood

Abstract

The totally isolated canine stomach, perfused with homologous blood, was used to study the inhibitory action of metiamide, a histamine antagonist of the H₂-blocking variety. Secretagogues, histamine or bethanechol chloride were infused separately or combined into the gastric artery for 6–7 h. When a basic secretion level was achieved after 2–3 h, metiamide was infused for 2 h, then infusion of secretagogue(s) continued for the remaining 2–3 h. Under all conditions of stimulation used in this study, metiamide significantly inhibited the concentration and output of HCl. In all stomachs studied there was a complete absence of titrable H⁺ at a certain stage of metiamide infusion or following such an infusion. These results indicate that the action of metiamide is not selectively limited to the antagonism of H₂-receptors. Metiamide acts against both H₂-receptors and muscarinic receptors.