Evidence against an acetylcholine releasing action of cisapride in the human colon.

The effect of cisapride (R51619) on intrinsic cholinergic nerve activity of human sigmoid taenia coli muscle strips (taenia) was assessed using radiolabelling techniques. Taeniae previously incubated with [3H]-choline were exposed to cisapride (0.41 and 4.1 microM), placebo solution and electrical field stimulation (EFS; 10 Hz, 1 ms, 200 mA for 480 pulses). Cisapride did not affect unstimulated (basal) release of radioactive material nor the release evoked by EFS. It was concluded that cisapride did not demonstrate a cholinomimetic effect in human sigmoid taenia coli muscle strips.