[氧自由基对大鼠心肌α1-肾上腺素能受体及其亚型的影响]

[Effects of oxygen free radicals on myocardial alpha 1-adrenoceptor and its subtypes in rat].

作者信息

Gong H B, Han Q D

机构信息

Institute of Vascular Medicine, Third Hospital, Beijing Medical University.

出版信息

Sheng Li Xue Bao. 1996 Feb;48(1):48-52.

PMID:8758690

Abstract

The effects of oxygen free radicals on myocardial alpha 1-adrenoceptor and its subtypes and beta-adrenoceptor were observed by the method of radioligand binding assay in rat. The experiments showed: (1) .OH and O??? reduced the Bmax of alpha 1-adrenoceptors binding to 125IBE2254 by 55% and 36%, respectively. (2) The KI values of alpha 1-adrenoceptors were increased by .OH (by 171%), but not by O2-. (3) Both .OH and O2-. increased the ratio of alpha 1A vs alpha 1B subtypes. (4) beta-adrenoceptors were not changed by either .OH or O2-. (5) Oxygen free radical scavengers mannitol and superoxide dismutase were capable of preventing the changes of alpha 1-adrenoceptor and its subtypes induced by oxygen free radicals. The above results suggest that oxygen free radicals can reduce the number and affinity of myocardial alpha 1-adrenoceptors, of which the alpha 1B subtype is more accessible to the changes.

摘要

采用放射性配体结合分析法，观察氧自由基对大鼠心肌α1 - 肾上腺素能受体及其亚型和β - 肾上腺素能受体的影响。实验结果表明：（1）·OH和O₂⁻分别使α1 - 肾上腺素能受体与¹²⁵I - BE2254结合的Bmax降低55%和36%。（2）·OH使α1 - 肾上腺素能受体的KI值升高（升高171%），而O₂⁻则无此作用。（3）·OH和O₂⁻均使α1A与α1B亚型的比例升高。（4）β - 肾上腺素能受体不受·OH或O₂⁻的影响。（5）氧自由基清除剂甘露醇和超氧化物歧化酶能够阻止氧自由基诱导的α1 - 肾上腺素能受体及其亚型的变化。上述结果提示，氧自由基可降低心肌α1 - 肾上腺素能受体的数量和亲和力，其中α1B亚型对这些变化更为敏感。