Neural isolation of the entire canine stomach in vivo: effects on motility

This study was designed to determine the effects of transection of all extrinsic and enteric neural continuity to the entire stomach on motility patterns of the stomach and small intestine. Five dogs were subjected to a model of orthotopic autotransplantation of the stomach to achieve an in vivo, "neurally isolated" stomach. Manometric catheters and serosal electrodes were implanted. A cyclic motor pattern occurred during fasting and was closely coordinated temporally with the migrating motor complex (MMC) in the small bowel. The period of the cyclic gastric motor activity did not differ from the period of the MMC in the small intestine [121 +/- 8 vs 124 +/- 10 (means +/- SE) min, P = 0.4], but the periods of both were greater than in control dogs (93 +/- 5 min, P less than 0.05). Tachygastria accounted for 36 +/- 13% of fasting myoelectric activity in the neurally isolated dogs and for less than 1% in control dogs. Plasma concentration of motilin was greatest during the phase III-like gastric motor activity; exogenous motilin induced premature phase III-like activity in the stomach and small intestine. Feeding abolished the cyclic motor activity in the stomach and decreased plasma motilin concentration. These data suggest that hormonal factors, and not extrinsic or intrinsic neural continuity to the stomach, may control both the initiation of a cyclic interdigestive gastric motor pattern and its temporal coordination with motor patterns in the small intestine.