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目的:研究α_1-肾上腺素受体各亚型介导的HEK293细胞中环腺苷一磷酸蓄积反应的特点。方法:(1)用磷酸钙沉淀法将编码三种亚型α_1-肾上腺素受体的全长cDNA分别转染到HEK293细胞中。(2)采用放射配基结合实验测定各亚型α_1-肾上腺素受体在HEK293细胞的表达量。(3)用[~3H]腺嘌呤掺入法测定环腺苷一磷酸蓄积率。结果:(1)各亚型激活后均使HEK293细胞中环腺苷一磷酸蓄积率呈浓度依赖性增加,并被α_1-受体选择性拮抗剂哌唑嗪阻断。(2)比较各亚型的药理学特性发现,在三种亚型中,α_(1A)-肾上腺素受体介导的效应最强,而α_1-肾上腺素受体各亚型对去甲肾上腺素的敏感性最高。结论:三种亚型α_1-肾上腺素受体均能介导HEK293细胞中环腺苷一磷酸的生成,并且在介导的效应和敏感性的高低等方面存在差异。
OBJECTIVE: To study the characteristics of cyclic adenosine monophosphate accumulation in HEK293 cells mediated by α 1 -adrenoceptor subtypes. Methods: (1) The full-length cDNA encoding the three α 1 -adrenoceptors was transfected into HEK293 cells by calcium phosphate precipitation. (2) Radioligand binding assay was used to determine the expression of α_1 -adrenergic receptor in HEK293 cells. (3) Cyclic adenosine monophosphate accumulation rate was measured by [~ 3H] adenine incorporation. Results: (1) After activation of each subtypes, the accumulation of cyclic adenosine monophosphate in HEK293 cells increased in a concentration-dependent manner, and was blocked by prazosin, α 1 -receptor selective antagonist. (2) Comparing the pharmacological properties of different subtypes, it was found that α 1A adrenoceptor had the strongest effect on all three subtypes, whereas the subtype of α 1 -adrenoceptor had the strongest effect on noradrenal Su is the most sensitive. CONCLUSION: All three subtypes of α 1 -adrenoceptors can mediate the generation of cyclic adenosine monophosphate in HEK293 cells, and there are differences in the mediation effect and sensitivity.