Abstract
The effects of the radial distension of the intestinal wall and the increased intraluminal pressure on the liberation of prostaglandins (PGs) were studied with the isolated guinea pig ileum. Both procedures were accompanied by an increased output of a prostaglandin-like substance and the release was proportional to the degree of distension or intraluminal pressure. Thin-layer chromatography coupled with bioassay suggested that this substance may be a mixture of PGF2α, PGE2 and PGE1. The existence of the former two types of PGs were prominent. The distension-induced release of PG-like substance was assumed to be not mediated by nerve excitation since tetrodotoxin failed to inhibit the release. The increased output of the PG-like substance was not maintained after distension of the intestinal wall, despite continued application of stimulus, indicating that actual tissue deformation is an essential condition leading to increased PG output. It is concluded that distension of the intestinal wall to its circumferential direction is an appropriate stimulus for the release of PG-like substance from the small intestine. The present results favor the view that prostaglandins may participate in the peristaltic activity.
