Inhibitory effect of ileal oleate on postprandial motility of the upper gut

To determine the effect of ileal oleate on postprandial gastrointestinal motility, duodenal and paired perfusion-aspiration ileal catheters and bipolar duodenal and jejunal electrodes were surgically implanted in five dogs. The ileum was perfused with either saline or an isotonic oleic acid emulsion at 2 ml/min. A 205-kcal mixed meal containing 120 ml liquid nutrient labeled with ¹¹¹In-diethylenetriamine pentaacetic acid (DTPA) and solid food labeled with ^99mTc was then administered orally. Gastric emptying was assessed by a gamma camera, myoelectric activity was continuously monitored, and duodenal-ileal transit of phenol red was determined over the ensuing 240 min. Ileal oleate reduced duodenal spikeburst frequency by 50% (P < 0.05) and delayed gastric emptying of liquids and solids. Four hours after ingesting the meal, 62% of solids and 34% of liquids were retained in the stomach during oleic acid perfusion compared with 25 and 4%, respectively, when saline was perfused (P < 0.05). Duodenal-ileal transit was markedly slowed by ileal perfusion with the oleic acid emulsion (P < 0.001). Ileal oleate therefore exerted a profound inhibitory effect on proximal gut motility in the early period after ingestion of a mixed-nutrient meal in dogs.