Motor responses to prostaglandin F2 alpha in isolated guinea pig fundus and antrum

While guinea-pig stomachs were isolated and oxygenated in organ baths. Continuous pressure recordings were made from separate fundic and antral pouches. Prostaglandin F2 alpha stimulated motor activity in both fundus and antrum mainly by elevation of wall tension, whereas the amplitude or frequency of the rhythmic activity was not significantly affected. The responses were dose-dependent and not significantly inhibited by atropine, mepyramine, or cimetidine. A direct effect mechanism of PGF2 alpha, independent of intramural cholinergic or histaminergic pathways, is indicated for both fundus and antrum.