[The effects of calcium channel blockers on the frequency and amplitude of the spontaneous contractions and the responses to acetylcholine on isolated rat duodenum].

The effects of calcium channel blockers on the frequency, amplitude of the spontaneous contractions and responses to acetylcholine are investigated in isolated duodenum of rat. Verapamil, diltiazem and nifedipine were used as calcium channel blockers. All the blockers decreased the frequency significantly. When the effects of verapamil, diltiazem and nifedipine were compared with each other, significant difference was not found. Nifedipine, diltiazem and verapamil significantly reduced the amplitude of spontaneous contraction by blocking the influx of calcium ions. On the other hand, they reduced the responses to acetylcholine significantly, comparing with control groups.