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研究了ＦＫ及维拉帕米（Ｖｅｒ）对离体心脏的作用，ＦＫ是从某植物中提取的急生物碱。ＦＫ能抑制兔离休右心房的自发性搏动频率，ＩＣ（５０）为４１．９μｇ／ｍｌ；浓度依赖性地抑制ＣａＣｌ_２在左心房及乳头肌的正性肌力作用，ＩＣ（５０）分别４２．８及１０５．７μｇ／ｍｌ，抑制强度明显弱于Ｖｅｒ。ＦＫ和Ｖｅｒ频率依赖性地抑制左心房收缩的阶梯现象，使正阶梯现象翻转为负阶梯，对静息后增强具有明显的抑制作用。上述实验结果表明：ＦＫ的钙拮抗作用主要是由于抑制细胞膜上通过电压依从性钙通道（ＰＤＣ）的钙内流和减少细胞内钙的释放来实现的。
The effect of FK and verapamil (Ver) on isolated hearts was studied. FK is an acute alkaloid extracted from a plant. FK inhibited the spontaneous pulsation frequency of the right atrium of the rabbits with IC (50) of 41.9μg / ml, and inhibited the inotropic effect of CaCl_2 in the left atrium and papillary muscles in a concentration-dependent manner. 8 and 105.7μg / ml, the inhibitory strength was significantly weaker than Ver. FK and Ver inhibited the left atrial contraction in a frequency-dependent manner, reversing the positive step to the negative step and significantly inhibiting the rest after resting. The above experimental results show that the calcium antagonism of FK is mainly due to the inhibition of calcium influx through the voltage-dependent calcium channel (PDC) on the cell membrane and the reduction of intracellular calcium release.