雌激素通过K_(ATP)通道影响大鼠肠系膜动脉的反应性

Estrogen affects reactivity of rat mesenteric artery through ATP-sensitive potassium channel

目的:观察雌激素对大鼠肠系膜动脉平滑肌ATP敏感性钾离子通道(KATP通道)mRNA表达的影响,探讨KATP通道在雌激素调节大鼠肠系膜血管反应性中的作用。方法:雌性SD大鼠48只,体重(100±10)g,随机分为假手术组(sham)、卵巢切除组(Ovx)和卵巢切除后补充雌激素组(Ovx+E)。采取实时荧光定量PCR检测大鼠肠系膜动脉中KATP通道mRNA的表达;观察各组大鼠肠系膜动脉对去甲肾上腺素(NE)升压效应的反应性。结果:与sham组相比,Ovx组大鼠肠系膜动脉KATP通道的Kir6.1及SUR2B亚单位mRNA表达减少(P<0.05),而Ovx+E组则表达增加(P<0.05)。与sham组相比,Ovx组大鼠的血管反应性明显增加(P<0.05),Ovx+E组无明显差异。给予KATP通道阻滞剂格列本脲后,sham组和Ovx+E组的动脉反应性增加(P<0.05),Ovx组无明显变化(P>0.05),此时3组间比较无明显差异(P>0.05)。结论:雌激素可能通过上调肠系膜动脉平滑肌细胞KATP通道的表达来降低动脉对去甲肾上腺素升压效应的反应性。

AIM： To observe the expression of ATP - sensitive potassium （ KA1v ） channel mRNA in mesenteric artery smooth muscle of rats with estrogen administration, and to evaluate the role of KATP channel in the effects of estro- gen on the reactivity of mesenteric artery in rats. METHODS ： Forty - eight female Sprague - Dawley rats, weighing （ 100 ＋ 10） g, were randomly divided into 3 groups： sham operation （sham） group, ovariectomy （Ovx） group and ovariectomy with estrogen administration （ Ovx ＋ E） group. The mRNA expression of KAye subunits in mesenteric artery smooth muscle was detected by quantitative real - time PCR. Artery reactivity in the rats was observed by norepinephrine - induced pressor response. RESULTS： Compared with sham group, the mRNA expression of KivS. 1 and SUPt2B was significantly de- creased in Ovx group （ P 〈 0. 05 ）, but increased in Ovx ＋ E group （P 〈 0. 0S ）. Compared with sham group and Ovx ＋ E group, the pressor response induced by norepinephrine in the rats were enhanced in Ovx group （ P 〈 0. 05 ）. No significant difference between sham group and Ovx ＋ E group was observed. After administered with glibenclamlde （ a KATP channel blocker）, the pressor response induced by norepinephrine was enhanced in sham group and Ovx ＋ E group, and no chan- ges in Ovx group. Meanwhile, no difference among the 3 groups was found. CONCLUSION： Estrogen up - regulates the expression of KATe channel subunits, which may be involved in estrogen - reduced pressor response to norepinephrine.