AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 2 445-R452, Copyright © 1995 by American Physiological Society
Intraluminal lipids modulate avian gastrointestinal motility
V. Martinez, M. Jimenez, E. Gonalons and P. Vergara
Department of Cell Biology and Physiology, Veterinary Faculty, Universitat Autonoma de Barcelona, Spain.
Infusion of lipids into the ileum delays gastric emptying and intestinal
transit time in some species. The aim of this study was to characterize the
actions of intraluminal lipid infusion on gastrointestinal electrical
activity in chickens. Animals were prepared for electromyography with
chronic electrodes in stomach, duodenum, and small intestine. Two catheters
were chronically placed in the esophagus and ileum to infuse equimolar
doses of either oleic acid (OA) or triolein (TO). Both OA and TO,
esophageally infused, inhibited the frequency of the gastroduodenal cycle
and increased the frequency of antiperistaltic spike bursts in the
duodenum. Ileal infusion of OA, but not of TO, produced the same effects.
Both esophageal and ileal OA infusion increased the duration of the
migrating myoelectric complex (MMC) and decreased the speed of propagation
of phase III. In conclusion, intraluminal infusion of lipids modulates
gastrointestinal motility by decreasing the frequency of the gastric cycle,
increasing duodenogastric refluxes, and elongating the MMC. These actions
could delay gastric emptying and increase transit time, which suggests the
presence of an "ileal brake" mechanism similar to that described in
mammals.
