A study of intestinal dysfunction induced by restraint stress in rats

Background: The pathogenesis of intestinal dysfunction induced by stress has not been established. We tried to clarify possible causal mechanisms of irritable bowel syndrome. Methods: An experimental model of intestinal dysfunction was designed using loading restraint stress in rats. A cannula was inserted into the origin of the duodenum or colon, with the other end leading to the skin. To provide intestinal content, a semi-solid colored marker was used for monitoring intestinal transit. After 1 week the marker was injected into the intestine through the cannula under unanesthetized wakefulness. Results: Under restraint stress, transit in the small intestine was suppressed, but actual suppression took place only in the upper half, where the contents normally moved fast. Transit time in the colon was reduced by restraint stress. This reduction was attributed to the disappearance of the stagnant region, which was present under normal conditions. Conclusions: These results suggested that restraint stress affects the function of the pacemaker site of the intestine.