Ambulatory small intestinal manometry. Detailed comparison of duodenal and jejunal motor activity in healthy man.

The aim of this study were to provide a detailed comparison of duodenal and jejunal motor activity in healthy individuals by utilizing prolonged ambulatory manometry in combination with computer-aided analysis. Intraluminal pressure profiles were studied in the duodenum and jejunum of 18 healthy volunteers over 24 hr. The subjects ingested two meals, both of 800 kcal and of equal chemical composition, at two different times of the day. Over the whole interdigestive period, phase III motor activity started more frequently distal than proximal to the ligament of Treitz. However, an increasing time of fasting was linearly related to an increasing number of phase IIIs originating proximal to the ligament of Treitz (r = 0.95). Both meals induced a postprandial motor pattern of similar duration and contractile activity. As compared to the jejunum, individual duodenal contractions during the postprandial period and during phase II had a higher duration and amplitude. Propagated clustered contractions occurred more frequently in the duodenum than in the jejunum, both in the interdigestive and digestive state. Jejunal clusters comprised a higher number of individual contractions of lower amplitude and duration. In healthy man duodenal and jejunal motor activity are different, both in the digestive and interdigestive state. The differences include the number of activity fronts traversing these segments of the gut, the number and organization of propagated clustered contractions, and subtle changes in the amplitude, duration, and coordinated propagation of individual contractions. These changes presumably reflect a regulatory capability of the small intestine to modulate the rate of transit of intraluminal content through different segments of the gut.