Effects of 16,16-dimethyl prostaglandin E2 on alkaline secretion in isolated canine gastric mucosa

An isolated fundic mucosal preparation of dog stomach which is capable of exhibiting an alkaline secretion is described. A stable secretion was established 40 min to 1 hr after the mucosa was pretreated with the H2-antagonist cimetidine to block spontaneous acid output. Alkaline secretion decreased when Ca2+ was removed from the nutrient solution. This secretion was stimulated by dibutyryl cyclic GMP, but was not altered by acetylcholine, carbachol, or 16,16-dimethyl PGE2. Alkaline secretion from a similar antral mucosal preparation was stimulated by 16,16-dimethyl PGE2. We conclude that the 16,16-dimethyl PGE2-stimulated bicarbonate secretion previously demonstrated in in vivo canine fundic mucosa is not the result of a direct effect of PG on gastric mucosal cells and that an intact blood circulation or cholinergic innervation is required for this action to occur.