Intestinal Propulsion in Restrained and Unrestrained Rats

The pattern of propulsion of a test meal in the small intestine of the rat has been studied. Between 5 and 45 minutes after administration of the test meal, the velocity of the meal was related inversely to the time after dosing, and declined exponentially with increasing distance from the pylorus. With every advance of 11% of intestinal length, the velocity of the meal was halved. When the rats were restrained in wire screens these relationships generally persisted despite a reduction in the over-all velocity with which the meal traversed the intestine. The persistence of this pattern strongly suggests the existence of a physiological mechanism which regulates the propulsive activity of the small intestine. DCI partially reversed the decrease in velocity in the restrained animals.