Transport of small bowel contents after interposition of an antiperistaltic jejunal segment in the rat.

The effect of antiperistaltic jejunal segments on small bowel transport was studied with an experimental technique permitting quantitative studies of propulsive as well as non-propulsive intestinal motility. 79 rats were provided with a permanent duodenal catheter and at the same laparotomy an anti- or isoperistaltic bowel segment based on 1, 2 or 3 mesenteric end-arcades was inserted at the midpoint of the jejunum. The evaluation of intestinal motility 1 week later indicated that an antiperistaltic segment of the rat jejunum has to be made at least 6 cm long, i.e. based on 3 mesenteric end-arcades in order to retard the propulsion of luminal contents. Not even this relatively long antiperistaltic segment was found to influence propulsion through bowel segments proximal to it, and distally the propagation velocity was accelerated. This implied that the total small bowel transit was unaffected. The non-propulsive intestinal motility, i.e. the mixing of small bowel contents was increased by the long reversed loop. The possible beneficial effect of antiperistaltic jejunal segments in short bowel syndrome and post-vagotomy diarrhoea in man may thus be attributed not to a retardation of the propulsive intestinal motility but to an increase in the non-propulsive intestinal motility.