Patterns of small intestinal motor activity during intraluminal infusion of elementary diets in dogs.

During continuous intraintestinal infusion of elementary diets, periodic fluctuation of the frequency of contractions has been observed. This study sought to characterize the temporospatial organization of this pattern and the influence of cholinergic input. Studies were performed on unanesthetized dogs with a duodenal cannula. Motor activity was recorded by means of infused catheters and external transducers. Nutrients were infused continuously at the duodenum and jejunal levels. Studies were repeated after administration of atropine. Six to 14 periodic variations of frequency of contractions during 10 basal infusion experiments were observed in random order. During duodenal infusion, atropine significantly increased the number of these events, associated with a synchronous pattern. Frequency and amplitude of contractions during jejunal infusion were significantly lower compared to duodenal infusion. Cyclic pattern elicited by nutrient infusion is related to a cholinergic mechanism; changes depend on the level of infusion.