Influence of urethane anesthesia and abdominal surgery on gastrointestinal motility in rats

The influence of various experimental treatments on propulsive gastrointestinal motility was examined in rats, using inulin as a marker. In unanesthetized rats without any surgery, the distribution center of inulin, which was expressed as a dimensionless distance normalized by the length of the small intestine, reached 0.587 down the intestinal tract from the pylorus 60 min after the intragastric administration of inulin. However, the distribution center of inulin moved only 0.061 in 60 min in unanesthetized rats with minimial abdominal surgery for intraduodenal administration of inulin, and did not move in unanesthetized rats with cannulas for perfusion or in the rats anesthetized with urethane and treated with abdominal surgery. In urethane-anesthetized rats without surgery, almost 100% of the inulin was recovered from the stomach 60 min after intragastric administration. These results suggest that gastrointestinal motility is extensively suppressed by minimal abdominal surgery as well as by anesthesia.