Effect of morphine on small bowel propulsion after intestinal ischemia.

OPIOIDS are known to reduce the motility of both the colon and the small intestine. However, some investigators have reported, both in animal models and in humans, that morphine increases duodenal motility. In vivo studies of the effect of morphine on small bowel motility are complicated because most have been performed in the postoperative period, where the additional trauma of laparotomy and bowel manipulation had already affected bowel motility. Previous studies have reported that intestinal ischemia also causes prolonged inhibition of bowel motility. The effect of morphine on intestinal motility has not been well assessed in situations in which ischemic injury to the bowel occurs without concurrent surgical injury. Recently, Zhang et al. reported that in a rat model of intestinal ischemia and reperfusion, pretreatment with morphine before ischemia and reperfusion markedly attenuated intestinal injury. The aim of the current study was to evaluate the effect of morphine on small bowel propulsion activity in a rat model in which controlled bowel ischemia was caused without concurrent abdominal surgery.