Effect of release of endogenous gastrin on myoelectrical and mechanical activity of isolated canine stomach

The myoelectrical and mechanical activities of the totally isolated, canine stomachs were recorded using five sets of bipolar silver-wire electrodes and one strain gauge. Stomachs were perfused extracorporeally with the blood of living supporting dogs which served as oxygenators and dialysers. Each supporting dog had a permanent antral pouch, accessible for the purpose of irrigation. To suppress the release of endogenous gastrin, this antral pouch and the antrum of the ex vivo stomach were irrigated with acid (pH 3). To induce the release of gastrin, one or both antra were irrigated with 0.2-percent acetylcholine or with 1 M glycine. To compare the action of endogenous gastrin with exogenous gastrin-like peptide, pentagastrin was infused into the gastric artery in doses of 4 mug/h and 8 mug/h. Control recordings were done during the acid irrigation. Endogenous gastrin released from antra by acetylcholine or glycine caused identical changes in the recordings as exogenous pentagastrin. There was a marked increase in the frequency of electrical control activity and of gastric contractions recorded as increased mechanical response. The results indicate that the ex vivo stomach can be used for study of the effect of endogenous gastrin musculature activity under the experimental conditions described.