Alpha1-adrenoceptor subtypes on rat afferent arterioles assessed by radioligand binding and RT-PCR.
Alpha1-adrenoceptor subtypes on rat afferent arterioles assessed by radioligand binding and RT-PCR.
复制标题
通过放射性配体结合和 RT-PCR 评估大鼠传入小动脉的 α1-肾上腺素受体亚型。
DOI：
10.1152/ajprenal.2001.281.1.f172
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Arendshorst,WJ
中科院分区：
文献类型：
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作者：
Salomonsson,M;Oker,M;Kim,S;Zhang,H;Faber,JE;Arendshorst,WJ
我们利用[3H]吡唑啉饱和和竞争放射配体结合研究来表征α1-肾上腺素受体在肾小球前血管中的表达。RT-PCR检测肾上腺素能受体亚型mRNA表达。用氧化铁筛法分离血管。[3H]prazosin结合到单一类结合位点（Kd0.087±0.012 nM， Bmax326±56 fmol/mg蛋白）。苯妥拉明取代[3H]吡唑嗪（0.2 nM）， pkip为8.37±0.09。与选择性α 1a -肾上腺素受体拮抗剂5-甲基脲地尔的竞争符合两个位点模型（pKi9.38±0.21和7.04±0.15）；59±3%为高亲和力结合位点，41±3%为低亲和力结合位点。与α 1d肾上腺素受体拮抗剂8-（2-[4-（2-甲氧基苯基）-1-哌嗪基]乙基）-8-阿兹匹斯罗[4.5]十二烷-7,9-二酮盐酸（bmy7378）的竞争符合低亲和力的单位点模型（pKi6.83±0.03）。α1A-、α1B-和α 1d -肾上腺素受体mrna相对含量分别为64±5%、25±5%和11±1%。因此，mRNA与亚型的受体结合之间存在非常好的相关性。这些数据表明大鼠肾阻力血管中α 1a型肾上腺素能受体占优势，α1B型和α 1d型肾上腺素能受体密度较小。
We utilized [3H]prazosin saturation and competition radioligand binding studies to characterize the expression of α1-adrenoceptors in preglomerular vessels. mRNA for adrenoceptor subtypes was assayed using RT-PCR. The vessels were isolated using an iron oxide-sieving method. [3H]prazosin bound to a single class of binding sites (Kd0.087 ± 0.012 nM, Bmax326 ± 56 fmol/mg protein). Phentolamine displaced [3H]prazosin (0.2 nM) with a pKiof 8.37 ± 0.09. Competition with the selective α1A-adrenoceptor antagonist 5-methylurapidil fit a two-site model (pKi9.38 ± 0.21 and 7.04 ± 0.15); 59 ± 3% of the sites were high-affinity, and 41 ± 3% were low-affinity binding sites. Competition with the α1D-adrenoceptor antagonist 8-(2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl)-8-azaspiro[4.5]decane-7,9-dione dihydrochloride (BMY-7378) fit a one-site model with low affinity (pKi6.83 ± 0.03). The relative contents of α1A-,α1B-, and α1D-adrenoceptor mRNAs were 64 ± 5, 25 ± 5, and 11 ± 1%, respectively. Thus there was a very good correlation between mRNA and receptor binding for the subtypes. These data indicate a predominance of the α1A-adrenoceptor subtype in rat renal resistance vessels, with smaller densities of α1B- and α1D-adrenoceptors.