Neural control of canine small intestinal motility during nonnutrient infusion

Our aim was to determine the effect of in situ neural isolation of the jejunoileum (extrinsic denervation and disruption of enteric neural continuity with the duodenum) on the spread of single pressure waves (SPW) and clustered contractions (CC) in response to increasing rates of isolated duodenal and jejunoileal nonnutrient infusions. Ten dogs were prepared with duodenal and jejunal infusion and manometry catheters and a diverting proximal jejunal cannula. Five of the dogs also underwent in situ neural isolation of the entire jejuno- ileum A noncaloric solution was infused at 0-15 ml/min into proximal duodenum or jejunum while manometric data were collected. Alterations in direction, distance, and velocity of spread of SPW and CC with increasing rates of intestinal infusion were analyzed by linear regression of responses to increasing infusion rates. Neural isolation of the jejunoileum did not markedly alter characteristics of duodenal or jejunal SPW or CC under conditions of no intestinal infusion. After neural isolation of jejunoileum, increasing rates of jejunal infusion decreased both the proportion and distance of antegrade spread of SPW in duodenum. These findings suggest that extrinsic innervation to the jejunoileum and enteric neural continuity with the duodenum do not regulate jejunal SPW or CC. Increasing rates of nonnutrient intestinal infusions do not alter local motor patterns in the innervated or neurally isolated jejunum, but after neural isolation of the jejunoileum, these infusions do alter characteristics of duodenal SPW by mechanisms independent of neural pathways.