以兔离体主动脉条为实验材料，观察ＥＦＴ对去甲肾上腺素（ＮＥ）、氯化钾（ＫＣｌ）和氯化钙（ＣａＣｌ２）的剂量－效应曲线的影响及主动脉条的α受体及β受体的作用．观察了ＥＦＴ对ＮＥ引起的兔主动脉条２种收缩成分的影响．结果ＥＦＴ能舒张已被氯化钙、高钾和去甲肾上腺素收缩的兔主动脉条，使ＮＥ、ＫＣｌ、ＣａＣｌ２的剂量－效应曲线非平行右移，最大效应降低．ＥＦＴ松驰血管平滑肌的作用不依赖于阻断α受体或β受体．而与戊脉安（Ｖｅｒ）相似，是通过阻断钙通道实现的．但它们阻断钙通道的方式不同．ＥＦＴ可能无选择性阻断电位依赖性钙通道和受体操纵性钙通道，而Ｖｅｒ则只选择性阻断．因此，ＥＦＴ的扩血管机制与其对钙通道阻断作用有关 The effect of EFT on the dose-response curve of norepinephrine (NE), potassium chloride (KCl) and calcium chloride (CaCl2) and the effect of EFT on α -receptor And β receptor role. The effect of EFT on NE-induced contractions of two aortic strips in rabbits was observed. Results EFT could relax the aortic strips contracted by calcium chloride, potassium and norepinephrine, and the dose-effect curves of NE, KCl and CaCl2 were non-parallel shifted to the right and the maximum effect was decreased. EFT relaxes the effects of vascular smooth muscle independent of blocking the alpha or beta receptors. Similar to verapamil (Ver), it is achieved by blocking calcium channels. But they block the calcium channels in different ways. EFT may not selectively block the potential-dependent calcium channels and receptor-operated calcium channels, whereas Ver selectively blocks only. Therefore, the vasodilator mechanism of EFT is related to its blockade of calcium channels