Postprandial inhibition of canine enteric interdigestive myoelectric complex.

Our aim was to determine whether the passage of postprandial duodenal chyme into the jejunum activates jejunal feedback mechanisms that inhibit the interdigestive myoelectric complex (IMC) of the canine small bowel. In five conscious dogs with 75-cm Vella loops of proximal jejunum and recording electrodes on the duodenum and the loop, intestinal myoelectric activity was recorded for approximately 4 h during fasting. The dogs were then given either a 200-g liver meal orally or they underwent perfusion of the jejunal loop with postprandial duodenal chyme collected from a donor dog given an identical liver meal. Before feeding, IMCs occurred at mean intervals of 126 +/- 16 (SE) min in the duodenum and 88 +/- 10 min in the loop. Feeding by mouth completely inhibited the IMCs in the duodenum but failed to inhibit the IMCs in the loop. However, perfusion of the jejunal loop with duodenal chyme suppressed the IMCs in both the loop and the duodenum. We concluded that postprandial inhibition of duodenal IMCs is mediated in part by neural and/or hormonal factors activated by chyme in the jejunum, whereas local factors inhibit jejunal IMCs. An enteric phase of postprandial IMC inhibition is postulated.