Effect of cisapride on myoelectrical and motor responses of antropyloroduodenal region during intraduodenal lipid and antral tachygastria in conscious dog.

Abstract

The myoelectrical and motor response of the antropyloroduodenal region to intraduodenal nutrient stimulation or antral tachygastria represent useful models for, respectively, physiological and pathophysiological gastric stasis to test the efficacy of prokinetic drugs. We evaluated the effects of an intravenous bolus of cisapride (0.63 mg/kg) on the myoelectrical and motor response of the antropyloroduodenal region to an intraduodenal triglyceride emulsion (10% Intralipid, 0.5 ml/min) or antral tachygastria in conscious dogs. Intraduodenal lipid suppressed antral motility (P < 0.05, compared to intraduodenal saline) and stimulated phasic pyloric contractions (P < 0.01, compared to intraduodenal saline), a motor pattern known to be associated with delayed gastric emptying. During intraduodenal lipid stimulation cisapride virtually abolished all isolated pyloric motor events (P < 0.05) and stimulated antral and duodenal motility (P < 0.05 for both) and antropyloroduodenal coordination (65% versus 15%; P < 0.05). Antral tachygastria was associated with a higher number of isolated pyloric motor events in the fasted state [0.8 (0.7-1.1) per minute versus 0.2 (0-0.3) per minute; P < 0.05], but not during intraduodenal lipid stimulation [1.1 (0.9-1.7) per minute versus 1.2 (1.0-1.9) per minute; NS]. Cisapride decreased the number and duration of spontaneous episodes of antral tachygastria during intraduodenal saline and lipid infusion (P < 0.05 for both) and abolished the tachygastria-associated motor patterns. Cisapride induced a 20% decrease in the antral slow-wave frequency during intraduodenal saline and lipid, irrespective of gastric pacemaker rhythm. We conclude that: (1) cisapride overcomes feedback from small intestinal lipid receptors on myoelectrical and motor activities of the antropyloroduodenal region and decreases antral slow-wave frequency, and (2) cisapride inhibits antral tachygastria and tachygastria-associated motor patterns. These effects may contribute to the effective gastrokinetic properties of cisapride in physiological and certain forms of pathophysiological gastric stasis.