大鼠尾动脉平滑肌中α肾上腺素受体的分析  

Analysis of α adrenoceptor in smooth muscle of rat caudal artery

作　　者：韩启德[1] 李金玲[1] Vladimir L BAKHILOV 

机构地区：[1]北京医科大学第三医院心血管研究室,北京100083 [2]俄罗斯莫斯科卢蒙巴友谊大学

出　　处：《中国药理学与毒理学杂志》1992年第3期214-217,共4页Chinese Journal of Pharmacology and Toxicology

基　　金：国家自然科学基金 № 3880393

摘　　要：采用离体血管收缩功能实验方法分析大鼠尾动脉平滑肌中α肾上腺素受体(α受体)各种亚型的组成及各自的功能意义,结果表明:尾动脉平滑肌中α_1,受体在功能上占绝对支配地位,包含α_(1A)与α_(1B)两种亚型,它们与去甲肾上腺素的亲和性相同,α_(1A)受体具有较大的储备,而α_(1B)受体无储备,前者在α_1受体激动剂致血管收缩效应中发挥主导作用,α_(1A)与α_(1B)受体之间可能存在协同效应。The contributions of subtypes of α adrenoceptor to contractions induced by agonists were studied in smooth muscles of the isolated rat caudal arteries. The results showed that the antagonizing effects of prazosin on the contractions induced by norepinephrine (NE), phenylephrine (Phe) or clonidine were more potent than those of yohimbine. In the meantime there were no differences among the potencies of prazosin or yohimbine on antagonizing NE, Phe and clonidine. Preincubation of the preparations with 50 μmol·L-1 chlorethylclonidine (CEC), after which only α1A adrenoceptors were left, reduced the maximal vascular contractions induced by NE or Phe to 67 and 76% of the control, respectively (P<0.05). While in the presence of 10 μmol ·L-1 nifedipine, during which only the responses of α1B adrenoceptors were left, the maximal contractions were reduced to 29and 47% of the control, respectively (P<0.05). There was no difference in the KA values between α1A and α1B subtypes, although both of them were significantly greater than those of the control. The ratios of KA and EC50 were about 3.3-3.6 in the control and in the α1A subtype, but those in the α1B subtype were not significantly different from the unity. The results above suggest that α1 adrenoceptors are superior functionally over α2 adrenoceptors in the smooth muscle of the rat caudal artery. Both subtypes of adrenoceptor,αa1A and α1B are involved in the contractile responses of activation of α1 adrenoceptor, in which α1A receptor plays a predominant role. Also there might be some synergetic mechanisms between α1A and α1B adrenoceptor.

关 键 词：α肾上腺素 受体 受体亚型 平滑肌 

分 类 号：R335.4[医药卫生—人体生理学]