哇巴因对血管紧张素Ⅱ及其1型和2型受体mRNA在心肌中表达的影响

目的观察哇巴因(Ouabain)对血管紧张素Ⅱ(AngⅡ)及其1型(AT1)与2型(AT2)受体mRNA在心肌中表达的影响。方法60只SD大鼠随机分为3组,分别为Ouabain组27.8 ng/(kg.d)Ouabain腹腔注射]、Losartan组27.8 ng/(kg.d)Ouabain腹腔注射,同时给予Losartan 30 ng/(kg.d)灌胃]、对照组(生理盐水2 mL/d腹腔注射),每周测定鼠尾血压,共6周。应用放免法测定各组大鼠血浆及心肌中AngⅡ质量浓度,同时采用实时定量荧光PCR(FQ-PCR)观察心肌中AT1和AT2mRNA表达的变化。结果血浆中的AngⅡ质量浓度在Ouabain组及Losartan组均显著高于对照组(P<0.05),而Ouabain组心肌中AngⅡ质量浓度无明显变化。与对照组相比,Ouabain组及Losartan组心肌中AT1mRNA与AT2mRNA的表达明显上调(P<0.05)。结论外周长期、慢性给予Ouabain后可持续升高SD大鼠的血压,并使RAS系统激活,这一作用可能是通过AT1受体介导。给予Ouabain激活AT1受体的同时,AT2活性也增加。

The expression of angiotensin Ⅱ and its subtype 1 and 2 receptors in the myocardium of ouabain-induced hypertensive rats

Objective To investigate how ouabain influence angiotensin Ⅱ(AngⅡ) and its subtype 1 and 2 receptors in the myocardium of ouabain-induced hypertensive rats.Methods 60 Sprague-Dawly(SD) rats were randomly divided into three groups: two experimental groups and a control group.One of the experimental groups was injected with 27.8ng/(kg·d) ouabain intraperitoneally,the other was injected with 27.8ng/(kg·d) ouabain and losartan 30ng/(kg·d).The control group was given placebo.Then,the blood pressure(BP) were measured every week and all rats were killed 6 weeks later.Radioimmunity and FQ-PCR were used to observe the changes of AngⅡ and its subtype 1 and 2 receptors in the myocardium of these ouabain-induced hypertension rats.Results Plasma AngⅡ of the ouabain-induced hypertension group was higher than that of the control group(P<0.05),but these was no change in the myocardium AngⅡ.AT_(1) mRNA and AT_(2)mRNA in the ouabaininduced hypertension group was remarkablely higher than that in the control group(P<0.05).Conclusion A long-term and peripheral administration of ouabain can raise blood pressure of rats,which may be induced by AT_(1) receptor.Ouabain can activate AT_(1) receptor as well as AT_(2) receptor.