EFFECT OF ENTERIC NONNUTRIENT INFUSIONS ON MOTOR PATTERNS IN NEURALLYINTACT AND NEURALLY ISOLATED CANINE JEJUNUM

Previous work in our laboratory has shown that nonnutrient mechanical factors initiate changes in motility patterns in local and remote regi ons of the small intestine. Our aims were to determine how isolated du odenal and jejunoileal nonnutrient infusions alter interdigestive moto r patterns locally and distantly and whether these effects are neurall y mediated. Ten dogs were prepared with duodenal and proximal jejunal infusion and manometry catheters and a proximal jejunal diverting cann ula. Five of these dogs served as neurally intact controls (Group 1) a nd five also underwent in situ neural isolation of the entire jejunoil eum (Group 2: extrinsic denervation; disruption of enteric myoneural c ontinuity with duodenum). After recovery, nonnutrient infusions at 0-1 5 ml/min for 5 hr into proximal duodenum or jejunum did not consistent ly affect cycling of the migrating motor complex (MMC). The period and duration of individual phases of the MMC and time to first phase III after the start of infusion were similar in both groups. In Group 2, d uodenal characteristics (period and duration of phase II, time to firs t phase III) increased slightly with increasing rates of jejunal but n ot duodenal infusion. Motility indices, although greater in Group 2, w ere not altered by enteric infusions. Differing rates of nonnutrient e nteric flow limited to duodenum or jejunoileum did not affect markedly local or distant motor patterns. Alterations in interdigestive motili ty patterns by postprandial nonnutrient intraluminal content are not m ediated directly by intraluminal flow. (C) 1995 Academic Press, Inc.