We investigate the recovery patterns of intestinal motility following postoperative ileus and evaluated the influences of epidural morphine administration (which is used to relieve the postoperative pain after abdominal surgery) on the migrating motor complexes (MMC) by using manometry and clinical assessment. The mean appearance time of MMC was 9.3 hours after surgery, and the cycle increased gradually with time. Clinical recovery signs (audible detection of bowel sounds and passage of flatus) of intestinal motility after surgery were confirmed later than the changes in MMC. Morphine induced premature-MMC waves higher in amplitude and longer in duration than spontaneous MMC. After the premature-MMC was induced by morphine, the spontaneous MMC with qualities similar to that observed before injection of morphine was reappeared. Serum concentrations of motilin and secretin were not changed by the morphine injection. These observations suggest that epidural morphine induced premature contractile activities may not be mediated any hormones but may be induced via gut opioid receptors. The morphine-induced contractions of intestine were distinct in pattern from the intestinal activity following postoperative ileus.

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