Effects of transection and reanastomosis on postprandial jejunal transit and contractile activity

Background. The purpose of this study was to determine how transection and reanastomosis of the intestinal wall influences postprandial motor activity and transit in the small intestine. Methods. Six dogs were each instrumented with 12 strain gauge transducers, two collection cannulas, and an infusion catheter defining a 100 cm study segment in the midjejunum. The animals underwent baseline measurements of postprandial motor activity and transit rate after 650 kcal solid and liquid meals. Postprandial motor activity was analyzed by computer methods that identify frequency, duration, amplitude, and propagation behavior of smooth muscle contractions. After the baseline measurements were performed, each animal underwent transection and reanastomosis of the intestinal wall at sites marked during the initial laparotomy. Measurements of postprandial motor activity and transit were repeated and compared with control values. Results. Transection decreased frequency, amplitude, and percent propagation for postprandial contractions. Total propagating area per minute significantly decreased from 382±20 gram-seconds/minute to 190±66 gram-seconds/minute after transection (p<0.05). Intestinal transit decreased from 13.5±1.5 cm/min to 8.5±2.4 cm/min (p<0.05). The change in transit was related primarily to a change in frequency of propagating contractions (r=0.767; p=0.004). Conclusions. Transection and reanastomosis of the intestinal wall changes the temporal and spatial organization of contractions distal to the transection site. The net result is fewer distally propagating contractions and slower intestinal transit.