Effects of neurohormonal agents on jejunal contraction spread and transit in the fed dog

The jejunal contraction patterns of dogs in response to intravenous infusion of neurotensin, somatostatin, secretin, and met-enkephalin were analyzed. The peptides were given after administration of a noncaloric viscous cellulose meal. A computer was used to determine the length of spread of contraction waves, their contraction force, the contraction frequency, and the motility index. Transit rates of luminal content were assessed videofluoroscopically. During saline infusion the cellulose meal was propelled aborally at a transit rate of 3.1 +/- 1.1 cm/s; the corresponding length of spread of contraction waves was 10.3 +/- 1.5 cm. All peptides decreased both the transit rate (0.45-1.81 cm/s) and the contraction spread (3.7-6.2 cm). Neurotensin increased the contraction force, but had no effect on contraction frequency and motility index. The other peptides reduced the motility index and the frequency and force of contractions. It was shown that the peptides influenced intestinal contraction patterns and the transit rate of luminal content. The length of spread of contraction waves was found to be most important in the regulation of transit.