The effect on intestinal fluid transport of exposing the serosa to hydrochloric acid. A study of mechanisms

Abstract

HCl (0.1 M) placed on the serosal surface of a jejunal segment evoked an intestinal secretion (rats) or inhibited a net fluid absorption (cats). In rats it was demonstrated that lidocaine (placed on the serosa of periarterially denervated intestinal segments), hexamethonium (given i.v.; innervated or denervated intestines) and indomethacin (given i.v.; denervated intestines) markedly inhibited the acid induced secretion, while atropine (given i.v.) had no effect. In the cat experiments it was shown that tetrodotoxin (given close i.a. [intraarterially] to denervated intestines) returned the rate of net fluid absorption to the control value observed before applying acid. Exposing the intestinal serosa to an acid solution apparently evokes a fluid secretion that is nervously mediated. Furthermore, it is proposed that prostaglandins are involved in the induction of the fluid secretion probably via a stimulation of nociceptors. The results may also have pathophysiological implications for some types of paralytic ileus.