Nervous control of migratory myoelectric complex of the small bowel

The effects on the migratory myoelectric complex (MMC) of transplantation of small bowel loops were investigated in miniature swine with chronically implanted bipolar electrodes. Four experimental models (A--D) were studied. In groups A and B, jejunal loops were either interchanged in sequence or transplanted to the ileum with preservation of intact neurovascular pedicles. In groups C and D, bowel segments were totally isolated and replanted in situ (group C) or as modified Thiry-Vella loops (group D). Weekly records of fasting myoelectrical activity were then taken. Group A and B animals showed reintegration of the transplanted bowel segments into a normal MMC sequence after a remodeling period. The replanted bowel segments of groups C and D displayed MMCs throughout the study period. The in situ replanted segments of group C were reintegrated into the normal sequence after a delay of 3--4 wk. These results indicate that the organization of the MMC is not solely determined by the extrinsic nervous system.