大鼠前列腺α1-肾上腺素受体亚型分析

用离体组织收缩功能实验和放射配体结合实验, 分析大鼠前列腺α₁-肾上腺素受体(α₁-AR)三种亚型的分布及其介导的收缩效应. 结果显示: 标本经用氯乙基可乐定(CEC)预处理后,去氧肾上腺素(PE)介导的最大收缩效应无明显下降, α₁-AR亚型选择性拮抗剂5-MU, WB4101, 萘哌地尔, 尼古地平, BMY7378抑制PE介导前列腺收缩的pA₂值与克隆α_1A-AR亚型的K_i值呈高度相关(r=0.91). 在放射配体结合实验中, 标本经CEC预处理后, ［¹²⁵I］BE与α₁-AR的最大结合容量由1.09±0.32 nmol·g^-1蛋白质明显下降至0.33±0.08 nmol·g^-1蛋白质. α_1A-, α_1B- , α_1D-AR密度分别约占总受体密度的15%, 65%和20%. 结果提示大鼠前列腺中尽管α₁-AR三种亚型均有分布, 但引起平滑肌收缩的功能性α₁-AR以α_1A-AR为主.

Analysis of α1-adrenoceptor subtypes on the rat prostate

The distribution of α₁-adrenoceptor(α₁- AR) subtypes and the functional role in Wistar rat prostates were studied by using functional experiment and radioligand binding assay. The results showed that the maximal contraction induced by phenylephrine (PE) was not decreased obviously after pretreatment with chloroethylclonidine (CEC). The pA₂ values of α₁-AR selective antagonists, 5-methylurapidil, WB4101, naftopidil, (+) niguldipine and BMY7378, for antagonizing PE-induced prostate contraction had a high correlative association with the p K_i values for cloned bovine α_1A-AR (r=0.91). In the radioligand binding assay, the maximal binding capacity of ［¹²⁵I］BE and α₁-AR decreased obviously after pretreatment with CEC,　which were 1.09±0.32 nmol·g^-1 protein and 0.33±0.08 nmol·g^-1 protein, respectively. The percentage of α_1A-, α_1B-and α_1D-AR was approximately 15%, 65% and 20%. These results indicate that the functional α₁-AR subtype inducing prostatic muscle contraction is α_1A- AR although there are three subtypes in rat prostate.