中年自发性高血压大鼠主动脉α_1肾上腺素受体亚型的改变

Alterations of α1-adrenoceptor subtypes in aorta of middle-aged spontaneously hypertensive rats

目的：研究１２月龄Ｗｉｓｔａｒ大鼠与同龄自发性高血压大鼠（ＳＨＲ）主动脉α１肾上腺。素受体（α１－ａｄｒｅｎｏｃｅｐｔｏｒ，α１－ＡＲ）亚型的分布。方法：采用离体灌流血管收缩功能实验和逆转录－多聚酶链式反应（ＲＴ－ＰＣＲ）方法，结果：ＳＨＲ与同龄Ｗｉｓｔａｒ大鼠相比，ＢＭＹ７３７８拮抗去甲肾上腺素（ＮＥ）缩血管效应的ｐＡ２值显著增大，ｓｅｒｔｉｎｄｏｌｅ的ｐＡ２值显著减小，而ＷＢ４１０１的ｐＡ２值无显著变化。ＣＥＣ预处理引起ＮＥ累积浓度－收缩效应曲线右移的作用显著增大。主动脉α１－ＡＲ３种亚型的ｍＲＮＡ稳态水平无明显改变。提示１２月龄ＳＨＲ主动脉中介导ＮＥ缩血管效应的α１－ＡＲ由对照组的α１Ａ－ＡＲ与α１Ｄ－ＡＲ亚型变为以α１Ｄ－ＡＲ亚型为主。

AIM and METHOD:Distribution of α1-adrenoceptor (α1-AR)subtypes in isolated aortae of 12 month-old Wistar rats and 12 month-old spontaneously hypertensive rats (SHR)were investigated by measurment of vasoconstrictor response and reverse transcript-polymerize chain reaction(RT-PCR)RESULTS:In the SHRs,compared with the age-matched Wistar rats,the pA2 value for BMY7378 on antagonizing norepinephrine(NE)induced vasoconstriction was increased,the pA2 value for sertindole was decreased,while the pA2 value for WB4101 was not changed.Chloroethylclonidine pretreatment shifted the concentration-response curves for NE to the right both in SHR and Wistar rats,but the shift was significantly greater in the former.RT-PCR showed that mRNA steady-state levels of all three α1-AR subtypes were not changed in SHR. CONCLUSION:The α1-AR to mediate the NE-induced constriction in aorta is changed from both α1Aand α1D subtypes in normal 12 month-old Wistar rats to α1D subtype alone in age-matched SHRThe change does not happen at mRNA level.