Effects of duodenal flow on interdigestive patterns of small bowel myoelectric activity

Factors regulating the conversion of the interdigestive migrating motor complex (MMC) to postprandial patterns of motility are not completely understood. This study assessed the effects of varying rates of nonnutrient duodenal flow on patterns of interdigestive motility before and after abdominal vagotomy. Six neurally intact dogs were prepared with serosal intestinal electrodes and a duodenal infusion catheter. After recovery, the dogs were studied by infusing an isosmolar, noncaloric, balanced electrolyte solution at rates of 0, 3, 6, 9, or 12 ml/min for 5 hours into the proximal duodenum. With increasing rates of duodenal infusion, the duration of phase I decreased progressively (P < 0.05), while the period of the MMC remained unchanged. The MMC was eventually inhibited at rates of 9 or 12 ml/min with establishment of a pattern of intermittent spike activity. These findings were similar in 3 of these dogs after transthoracic total abdominal vagotomy. Our findings suggest that increases in duodenal infusion rate, independent of caloric or nutrient content, modulate patterns of intestinal motility during the postprandial period; this effect does not appear to be vagally mediated.