Effects of neurotensin on motor patterns of canine duodenum and proximal jejunum

Abstract

The aim of this study was to clarify if small doses of neurotensin (2.5 and 5.0 pmol∙kg−1∙min−1, i.v.) in dogs alter the postprandial motor pattern of the duodenum in comparison with the adjacent jejunum. The intestinal motor patterns were quantified by means of closely spaced strain gauge transducers and a computerized method. An acaloric viscous meal of cellulose was used to induce postprandial motility. Gastric emptying was measured radiographically. During intravenous control infusion of saline, the characteristics of duodenal and jejunal motor pattern were significantly different. The duodenum contracted at a lower rate and showed a higher incidence of stationary contractions. The lower dose (2.5 pmol∙kg−1∙min−1) of neurotensin showed no significant effects, whereas the higher dose (5 pmol∙kg−1∙min−1) significantly slowed gastric emptying and altered the motor pattern of both intestinal segments in a similar manner. It reduced the number of contractions, shortened the contraction spread, increased the incidence of stationary contractions, and decreased the incidence of propagated contractions. The alterations of motility caused enhanced mixing of luminal contents. The differences in motor patterns seen in the control state between both intestinal segments were diminished during neurotensin. Data revealed no differences in sensitivity of the duodenum and jejunum to neurotensin. Results suggest that neurotensin is one of the gastrointestinal peptides involved in regulating intestinal contractile patterns.Key words: intestinal motility, gastrointestinal hormones, neurotensin, contractile patterns.