Electromyographic characteristics of small bowel motility in the rat

Rats are widely used in intestinal motility studies, but no precise observation has yet been carried out on the organization of motility throughout the whole small bowel of the rat. The aim of this work was to investigate the characteristics of small intestinal motility of the rat using an electromyographic technique. The variables describing the pattern of occurrence of the migrating myoelectric complex (MMC) were studied as well as the relative distribution of the 3 phases within the MMC cycles. The mean duration of the MMC was 20 min on the jejunum, and it increased up to twofold along the ileum. The propagation of the MMCs was regular in the jejunum, but about half the MMCs disappeared along the ileum and did not reach the caecum. The electromyographic characteristics of the jejunum are greatly different from those of the ileum, and the motility of a segment is not representative of the whole small bowel motility. Considering these particularities of intestinal motility, rats differ in many details from other species.