EFFECT OF CISAPRIDE ON MYOELECTRICAL AND MOTOR-RESPONSES OF ANTROPYLORODUODENAL REGION DURING INTRADUODENAL LIPID AND ANTRAL TACHYGASTRIA IN CONSCIOUS DOG

The myoelectrical and motor response of the antropyloroduodenal region to intraduodenal nutrient stimulation or antral tachygastria represen t useful models for, respectively, physiological and pathophysiologica l gastric stasis to test the efficacy of prokinetic drugs. We evaluate d 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) o r antral tachygastria in conscious dogs. Intraduodenal lipid suppresse d antral motility (P < 0.05, compared to intraduodenal saline) and sti mulated phasic pyloric contractions (P < 0.01, compared to intraduoden al saline), a motor pattern known to be associated with delayed gastri c 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 antropyloroduode nal coordination (65% versus 15%; P < 0.05). Antral tachygastria was a ssociated 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 decreas ed the number and duration of spontaneous episodes of antral tachygast ria during intraduodenal saline and lipid infusion (P < 0.05 for both) and abolished the tachygastria-associated motor patterns. Cisapride i nduced a 20% decrease in the antral slow-wave frequency during intradu odenal 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 antropylo roduodenal region and decreases antral slow-wave frequency, and (2) ci sapride 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 pathoph ysiological gastric stasis.