MODULATION OF THE MIGRATING MYOELECTRIC COMPLEXES BY CHOLECYSTOKININ AND GASTRIN IN THE GASTROINTESTINAL-TRACT OF CHICKENS

Several mammalian avian species, including the chicken, show migrating myoelectric complexes (MMC) both in unfed and fed states. In these sp ecies, postprandial hormones seem to modulate but not to disrupt the M MC. To gain more information in this modulatory role, we evaluated the role of cholecystokinin (CCK) vs gastrin on the regulation of intesti nal motility in chickens. Birds were implanted with eight electrodes f or electromyography in the stomach, duodenum, jejunum, and ileum. In f eed-deprived animals, CCK infusion (10(-12) mol/kg per min x 3 h) did not disrupt the MMC but induced changes in the MMC pattern similar to those induced by a meal. Infusion of CCK in fed animals induced dose-d ependent effects: CCK infused at 10(-11) and 3 x 10(-11) mol/kg per mi n x 2 h, progressively elongated the MMC and slowed the speed of propa gation of Phase 3. Furthermore, CCK infused at 10(-10) mol/kg per min x 2 h disrupted the MMC but a Phase 3 appeared just after the end of t he infusion. By contrast, chicken gastrin (10(-10) mol/kg per min x 2 h) did not modify the MMC pattern. Ln conclusion, CCK influence on the intestinal motility of chickens ranges from the modulation of the MMC to total disruption, depending on the dose. Moreover, this study sugg ests that the mechanism of action of CCK could be similar in both mamm alian and avian small intestines.