Release and replenishment of acetylcholine in intestinal wall of guinea pig

Abstract

The total acetylcholine (ACh) content of the guinea pig ileum decreased (10–20%) immediately after circumferential stretching. Morphine was found to inhibit the decrease in the ACh content, while smooth muscle stimulants (ACh, histamine and KCl) exhibited no remarkable effect on the process. After ceasing the stretching the ACh content was restored within 15 seconds to the initial level. Successive peristalses also were found to result in a decrease in the ACh content of the intestinal wall. In relation to the circumferential stretching of the intestinal wall, a possible scheme of the sequence of reactions, comprising rapid release of ACh followed by decomposition and resynthesis, occurring during the course of stretching and relaxing of the intestine, is discussed.