HISTAMINE H2‐ANTAGONISTS MODIFY GASTRIC EMPTYING IN THE RAT

Abstract

Histamine H2‐receptor antagonists were tested for their effect on gastric emptying in the rat. At low doses all the compounds were inactive except for burimamide which delayed and ranitidine which accelerated gastric emptying. At high doses burimamide, metiamide, Cimetidine and oxmetidine delayed, whereas ranitidine accelerated gastric emptying; tiotidine remained ineffective. Changes in emptying rate were not accompanied by changes in emptying pattern which, with all the compounds examined, proceeded, as in the controls, by apparent first order kinetics. The mechanism of the ranitidine‐induced acceleration of gastric emptying seemed to be connected with an interference with the cholinergic system, whereas the mechanism of cimetidine‐ and oxmetidine‐induced slowing of gastric emptying was apparently related to cholinolytic and possibly also relaxant effects of the compounds. These different effects of the various H2‐blockers are consistent with the idea that changes in emptying rate are independent of H2‐receptor blockade. 1982 British Pharmacological Society