Postprandial disruption of migrating myoelectric complex in dogs. Hormonal versus extrinsic nervous factors

Our aim was to determine the mechanism whereby the jejunoileum regulates postprandial gastroduodenal motility. Five dogs were prepared with a proximal jejunal infusion catheter and with gastric manometry catheters and serosal intestinal electrodes for recording gastric and intestinal motility. After two weeks, fasted dogs were studied during jejunal infusion of either isosmolar NaCl (154 mM) or isosmolar mixed nutrient solution (50% Meritene) on four separate days each. After completion of these baseline studies, the dogs underwent a model of autotransplantation of the entire jejunoileum (extrinsic denervation, disruption of intrinsic neural continuity with proximal duodenum). Two weeks later, identical studies as before were repeated with the now "autotransplanted" jejunoileum. Before transplantation, infusion of NaCl did not interrupt the characteristic interdigestive migrating motor complex either in the gastroduodenum or in the jejunoileum. However, infusion of nutrients interrupted the migrating motor complex both in the gastroduodenum and jejunoileum for the duration of the infusion (5 hr). After autotransplantation of the jejunoileum, the migrating motor complex continued to occur in the gastroduodenum and in the jejunoileum during infusion of NaCl, but the migrating motor complex cycled independently in each region without any temporal coordination. Jejunal infusion of nutrients interrupted the MMC in both regions for the duration of infusion (5 hr). Because inhibition of the gastroduodenal and jejunoileal migrating motor complex continued to occur during infusion of nutrients into the transplanted jejunum, we concluded that jejunoileal regulation of postprandial inhibition of interdigestive motility in the stomach and duodenum is mediated by hormonal factors and does not require intrinsic neural continuity.