IN-SITU NEURAL ISOLATION OF THE ENTIRE CANINE UPPER GUT - EFFECTS ON FASTING AND FED MOTILITY PATTERNS

Background. Multiorgan upper gut transplantation is becoming clinicall y feasible; however, the effects of multivisceral transplantations on gastrointestinal motility are unknown. Our aim was to determine the ne ural and hormonal mechanisms controlling motility patterns after compl ete extrinsic denervation of the upper gut as a model of multivisceral upper gut autotransplantation. Methods. Seven dogs successfully under went in situ neural isolation of the stomach, entire small intestine, proximal colon, liver, and pancreas by transecting all connections (di stal esophagus, midcolon, all nerves, lymphatics) to this multiviscera l complex except the celiac artery, superior mesenteric artery, and th e suprahepatic and infrahepatic vena cava; these vessels were meticulo usly stripped of adventitia under optical magnification. Blood flow wa s not disrupted to prevent confounding effects of ischemia-reperfusion injury. After 1- to 2-week recovery, myoelectric and manometric recor dings of stomach and myoelectric recordings of small bowel were obtain ed from conscious animals. Results. During fasting the characteristic cycling migrating motor complex (MMC) was observed in the stomach and small intestine. The gastric component of the MMC was absent in one of the seven dogs. Regular cycling of the MMC during fasting, however, w as intermittently disrupted and replaced by a noncyclic pattern of int ermittent contractions in two of seven dogs 43% of the recording time. A small meal (50 gm liver) did not abolish the MMC as occurs in norma l dogs; in contrast, a large meal (500 gm liver) did abolish the MMC. Conclusions. Extrinsic innervation to the upper gut modulates but is n ot requisite for interdigestive and postprandial motility of the stoma ch. Because relatively normal global motility patterns are preserved, multivisceral upper gut transplantation should be a viable option in s elected patients.