The increase in cyclic AMP content in the isolated guinea pig gastric mucosa during histamine-stimulated acid secretion

Using the isolated guinea pig gastric mucosa perfused in vitro with a constant acid secretion and potential difference, the cyclic AMP (cAMP) contents in the gastric mucosa and in the serosal solution were measured during the course of acid secretion stimulated by histamine or dibutyryl cyclic AMP (db-cAMP). (1) The acidsecreting response of the gastric mucosa to histamine was reproduced by addition of db-cAMP. (2) The acid secretion stimulated by db-cAMP was not inhibited by cimetidine whereas the histamine-stimulated acid secretion was inhibited. (3) The increase in mucosal cAMP content was accompanied by histamine-stimulated acid secretion. (4) The increase in the mucosal cAMP content preceded the increase in acid secretion stimulated by histamine. From these findings, it has been concluded that cAMP plays an important role in the mechanism of histamine-stimulated acid secretion, including the morphological transformation of parietal cells, although its role as the intracellular mediator of the stimuli for the hydrogen ion pump itself requires further investigation.