Effects of cisapride on postcibal jejunal motor activity

In the jejunum of fasting humans, cisapride induces a phase 2-like, highly propagative motor pattern. This study investigated cisapride's effects on the fed pattern of the jejunum. Starting 5 min after a phase 3 of the migrating motor complex, 18 healthy men received 5 or 10 mg cisapride or placebo orally in random double-blind fashion and ingested meals containing 1000 and 4200 kJ, respectively. Jejunal pressures were recorded pneumohydraulically with five catheter orifices 10-30 cm aboard the ligament of Treitz. After the 4200-kJ meal, total number and number of propagated contractions as well as area under the curve increased significantly more than after 1000 kJ. Following the 1000-kJ but not the 4200-kJ meal, 10 mg cisapride increased total number of contractions, number of propagated contractions, mean amplitude, and area under curve significantly more than placebo. Fed-pattern duration increased with the meal's caloric content but was not influenced systematically by cisapride. In conclusion, cisapride stimulates jejunal motor activity and induces a propagative pattern after a 1000-kJ but not after a 4200-kJ meal, suggesting that it can produce no further stimulation when motor activity is near maximally enhanced already.