AMBULATORY SMALL-INTESTINAL MANOMETRY - DETAILED COMPARISON OF DUODENAL AND JEJUNAL MOTOR-ACTIVITY IN HEALTHY MAN

The aims of this study were to provide a detailed comparison of duoden al and jejunal motor activity in healthy individuals by utilizing prol onged ambulatory manometry in combination with computer-aided analysis . Intraluminal pressure profiles were studied in the duodenum and jeju num of 18 healthy volunteers over 24 hr. The subjects ingested two mea ls, both of 800 kcal and of equal chemical composition, at two differe nt times of the day. Over the whole interdigestive period, phase III m otor activity started more frequently distal than proximal to the liga ment of Treitz. However, an increasing time of fasting was linearly re lated to an increasing number of phase IIIs originating proximal to th e ligament of Treitz (r = 0.95). Both meals induced a postprandial mot or pattern of similar duration and contractile activity. As compared t o the jejunum, individual duodenal contractions during the postprandia l period and during phase II had a higher duration and amplitude. Prop agated 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 m otor activity are different, both in the digestive and interdigestive state. The differences include the number of activity fronts traversin g 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 change s presumably reflect a regulatory capability of the small intestine to modulate the rate of transit of intraluminal contents through differe nt segments of the gut.