瓜蒌提取物对离体家兔胸主动脉条收缩的影响

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

Effect of Extract of Fructus Trichosanthis on the Tension of Isolated Rabbit Aortic Strips

To evaluate the effect of extract of Fructus Trichosanthis(EFT) on aortic strip's tension,the fluctuation of the dose response curves for NE,KCl and CaCl 2 induced by EFT was observed with isolated rabbit aortic strips.Effect of EFT on α adrenoceptor or β adrenoceptor and influence of EFT on the 2 components of NE evoked contraction were studied.EFT inhibited the contractions evoked by CaCl 2,high K + or NE in rabbit thoracic aortic strips.EFT shifted the dose response curves of NE,KCl and CaCl 2 to the right,and depressed their maximal responses.EFT produced neither α adrenoceptic blocking nor β adrenoceptic stimulating effects.EFT induced relaxation on vascular smooth muscle resulted from its antagonistic effect to Ca 2+ and the mode of this antagonism differed from that of Verapamil.EFT inhibited both the receptor operated channel and potential dependent channel.On the contrary,Ver inhibited the potential dependent channel only.The mechanism of vasodlatation of EFT is related to its antagonistic effect on calcium ion.