Effects of prostaglandins E1 and E2 on human, guinea-pig and rat isolated small intestine.

1. Prostaglandins E(1) and E(2) contracted the longitudinal muscle of human, guinea-pig and rat isolated ileum.2. The site of action varied with the species. In the rat and in some strips of human tissue prostaglandin appeared to have only a direct action on or in the muscle cells. In the other strips of human tissue and in guinea-pig ileum the prostaglandins seemed to stimulate both the intrinsic cholinergic nerves and the muscle cells.3. In contrast to the longitudinal muscle, the circular muscle of human, guinea-pig and rat isolated ileum was usually inhibited by prostaglandin, apparently by an action directly on the muscle cells.4. Prostaglandins may play a part in the control of intestinal motility.