NEURAL CONTROL OF CANINE SMALL-INTESTINAL MOTILITY DURING NONNUTRIENTINFUSION

Our aim was to determine the effect of in situ neural isolation of the jejunoileum (extrinsic denervation and disruption of enteric neural c ontinuity with the duodenum) on the spread of single pressure waves (S PW) and clustered contractions (CC) in response to increasing rates of isolated duodenal and jejunoileal nonnutrient infusions. Ten dogs wer e prepared with duodenal and jejunal infusion and manometry catheters and a diverting proximal jejunal cannula. Five of the dogs also underw ent in situ neural isolation of the entire jejunoileum. A noncaloric s olution was infused at 0-15 ml/min into proximal duodenum or jejunum w hile manometric data were collected. Alterations in direction, distanc e, and velocity of spread of SPW and CC with increasing rates of intes tinal infusion were analyzed by linear regression of responses to incr easing infusion rates. Neural isolation of the jejunoileum did not mar kedly alter characteristics of duodenal or jejunal SPW or CC under con ditions of no intestinal infusion. After neural isolation of jejunoile um, increasing rates of jejunal infusion decreased both the proportion and distance of antegrade spread of SPW in duodenum. These findings s uggest that extrinsic innervation to the jejunoileum and enteric neura l continuity with the duodenum do not regulate jejunal SPW or CC. Incr easing-rates of nonnutrient intestinal infusions do not alter local mo tor patterns in the innervated or neurally isolated jejunum, but after neural isolation of the jejunoileum, these infusions do alter charact eristics of duodenal SPW by mechanisms independent of neural pathways.