Effects of CCK Antagonists on Intestinal Motility in Dogs

Abstract

The motility of the canine small and large intestine consists of cyclic motor patterns which are controlled by neural and hormonal factors. During the interdigestive state, a specific motor pattern called the migrating motor complex (MMC) occurs rhythmically in the small intestine. The MMC cycle is characterized by four phases: Phase one has little or no activity, phase two has intermittent and irregular contractions, during phase three the bowel contracts at its maximum frequency, and phase four is the following transition period back to quiescence. Phase three of the MMC is migrating aborally along the bowel. A meal sharply interrupts the MMC cycle and causes a prolonged increase in irregular contractile activity similar to phase two activity [2,14,22]. The canine colon also shows a cyclic motor pattern called the colonic motor complex (CMC), consisting of rhythmic bursts of tonic and phasic contractions [16]. After a meal the cyclic motor pattern of the colon is not interrupted but the motor activity is increased in the distal half of the colon. This is called the gastrocolonic response [15].

Dr. Karaus and Dr. Niederau were supported by grants from the Deutsche Forschungsgemeinschaft (Ka 631/5–1 and Ni 224/2–2).