Changes in antroduodenal resistance induced by Cisapride in conscious dogs

The effects of Cisapride on gastric outflow/pressure relationships have been examined in conscious dogs. In the digestive state, after inhibition of emptying in the first 10 min, Cisapride accelerated gastric emptying for 110 min by increasing the volume (7.3 +/- 1.2 vs. 2.3 +/- 0.3 ml) rather than by decreasing the interval between flow pulses (4.9 +/- 0.2 vs. 4.5 +/- 0.1s). After non-nutrient gastric loading, Cisapride also first inhibited and then accelerated gastric emptying as the consequence of both a larger stroke volume (8.0 +/- 1.7 vs. 3.2 +/- 0.5 ml) and more frequent pulses (3.9 +/- 0.1 vs. 4.9 +/- 0.1 s). In both situations, Cisapride increased the amplitude of the antral/pyloric pressure waves. Antropyloroduodenal resistance increased substantially in the first 10 min after Cisapride then recovered to its control value. We conclude that stimulation of antropyloroduodenal motility by Cisapride can both impede and increase gastric emptying by changes in antroduodenal resistance.