Effect of CCK-OP and intraduodenal administration of essential amino acids on intraluminal pressures of sigmoid and rectum in patients with Chagasic megacolon.

The motility of the sigmoid colon and rectum was studied by manometry in patients with Chagasic megacolon and in control individuals using two different experimental procedures: (1) intravenous infusion of saline, followed by intravenous infusion of cholecystokinin octapeptide (OP-CCK) at the dose of 20 ng/kg/hr; and (2) intraduodenal instillation of saline followed by a solution of essential amino acids at a flow of 10 ml/min. CCK-OP induced an increase in motility index in the sigmoid colon (P less than 0.05) and rectum (P less than 0.05) in the controls, whereas intraduodenal infusion of amino acids produced a significant increase in motility index exclusively in the sigmoid colon (P less than 0.005). A significant increase (P less than 0.05) in sigmoid colon motility also occurred in the control group after duodenal saline infusion was interrupted. The release of other substances in addition to CCK must have been responsible for the different behavior of sigmoid colon and rectum in response to the stimuli used. Neither procedure caused significant changes in the motility of the sigmoid colon or the rectum of the Chagasic patients. The extensive intramural denervation occurring in Chagasic megacolon probably destroys the neural pathway through which OP-CCK and the substances released by the duodenum by the infusion of essential amino acids activate the motor cells of the human terminal intestine.