Correlation of contractions and transit in rat small intestine

Abstract

A single strain gauge was implanted chronically in the proximal jejunum of the rat to record contractions. FAsted pentobarbital-anesthetized animals received glucagon, caerulein, or isotonic saline control infusions intravenously while contractions were recorded. In control animals, the distribution of contractions in time showed clusters, with peaks at intervals of 14.24 +/-5.6 (SD) min. Glucagon produced dose-related inhibition of contractions. Caerulein at two lower doses produced a more uniform distribution of contractions in time; a higher dose caused inhibition. In other fasted rats, an isotopically labeled bolus was given through a chronically implanted duodenal cathether, and its distribution along the small intestine was examined in animals receiving the same doses of glucagon, caerulein, and saline. Glucagon caused a dose-related delay in transit. Those doses of caerulein that produced a uniform distribution of contractions accelerated transit; the dose that inhibited contractions delayed transit. Doses of glucagon and caerulein known to affect both motility and transit did not significantly affect water movement. The fasted rat resembles the fasted go in respect to the temporal distributions of jejunal contractions at a single point. Both quantitative and qualitative changes in contractions induce changes in transit.

Telemetric Small Intestinal Motility Recording in Awake Rats

“…The mean duration of the MMC for Sprague-Dawley rats was 14.2 B 2.3 min in a previous study [13], a duration very similar to that observed by us. Compared to the telemetric method in pigs [6], no abdominal fistulas were needed and electromyographic signals could be detected from any part of the gastrointestinal tract.…”

Role of Bile in Intestinal Motility After Massive Liver Resection in Conscious Rats

“…The MMC after 90% PHx was characterized by an increased duration of Phase 2-like activity. Both quantitative and qualitative changes in contractions clearly induced changes in gastrointestinal transit [14]. These findings suggest FIG.…”

“…It is interesting to note that the MI at 1 day after surgery was higher than those at 3 days after surgery in 90% PHx ϩ bile groups. Although the mechanism remains unclear, this result may be associated with decreased intestinal sensitivity to bile because of higher levels of glucagon, which is related to inhibited gastrointestinal motility [14] in blood at 3 days after 90% PHx than at 1 day after 90% PHx [19].…”

Study of Small Bowel Transport Pattern in Fasted, Conscious Rats with an Intact Gastrointestinal Tract

“…It is thought to function as an 'interdigestive housekeeper' that sweeps the small bowel from debris etc. (17)(18)(19)(20). Ruckebusch and Fioramonti (21) found that in the duodenum of the rat, these cycles recur at the rate of about one per 20 min, and that the MMCs have a role in the propulsion of the test meal.…”