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硝普钠(亚硝基铁氰化钠,Sodium nitroprusside)的降压作用有人认为是由于亚硝基部分。但亚硝酸盐的效力比硝普钠小50倍,而对平滑肌的作用时间短得多。硝普钠的主要作用部位是血管平滑肌。使氯化钾所致的兔主动脉条收缩减少一半所需硝普钠的浓度是6.4×10~(-5)M,而松弛去甲肾上腺素所致的收缩的一半所需浓度为5×10~(-8)M。对子宫或十二指肠平滑肌不起作用,对离体心肌也无作用。对阻力动脉和静脉
The hypotensive effect of sodium nitroprusside is thought to be due to the nitroso moiety. But nitrite is 50 times less effective than sodium nitroprusside and has a much shorter duration of action on smooth muscle. Sodium nitroprusside’s main site of action is vascular smooth muscle. The concentration of sodium nitroprusside required to reduce the contraction of rabbit aortic strips by potassium chloride by half is 6.4 × 10 -5 M and the concentration required for the relaxation of noradrenaline-induced contractions is 5 × 10 ~ (-8) M. Uterine or duodenal smooth muscle does not work on the isolated myocardium also had no effect. Resistance to arteries and veins