【摘要】 将含有α1肾上腺素受体（α1－AR）三种亚型的全长cDNA质粒分别转染到人胚胎肾脏细胞（HEK293），α1A－，α1B-和α1D－AR在HEK293细胞株上得到高水平稳定表达（Bmax达pmol／mg水平），用3H－inositol标记和柱层析法测定细胞磷酸肌醇蓄积。观察在去甲肾上腺素（NE）长期作用下α1三种受体亚型介导磷酸肌醇蓄积敏感性降低的差别。结果表明，α1三种受体亚型介导的磷酸肌醇蓄积效应的减弱与NE预温育的时间和浓度呈依赖关系。在激动剂持续作用下α1三种受体亚型发生脱敏的过程不同，其中α1－AR脱敏发生最快，脱敏所需NE的浓度最低；α1D－AR脱敏最慢，所需NE的浓度最高；α1B－AR介于上述两者之间。更多还原

【Abstract】 cDNAs for the bovine α1A-, hamster α1B- and rat α1D-adrenoceptors (AR) weretrans fected into human embryonic kidney 293 (HEK293) cells by calcium phosphateprecipitation and stably expressed at high levels. The inositol phosphates (InsPs) accumulation was measured by the method of 3H-inosito1 incorporation and column chromatography. Susceptibilities to the desensitizaton of α1-AR subtypes-mediated lnsPs accumulation were determined in HEK 293 cells stimulated sustainedly by norepinephrine(NE). The NE-induced InsPs accumulation showed progressive decrease by NE pretreatment with increasing time of preincubation and concentration of NE in the cellstrans fected with all the α1-AR subtypes. However, susceptibilities to the desensitizationwere different among the three subtypes. The desensitization of α1A-AR took place earliest and needed lowest concentration of NE. The desensitization of α1D-AR appeared tobe the latest and needed hightest concentration of NE, while α1B-AR stood in between.更多还原