Gout B
Department of Pharmacology A, Centre de Recherche Pierre Fabre, Castres, France.
Life Sci. 1988;43(24):1961-71. doi: 10.1016/0024-3205(88)90569-3.
The biochemical exploration of the alpha 2-adrenergic receptors was investigated in the canine saphenous vein using the highly selective alpha 2-adrenergic antagonist rauwolscine as a tritiated ligand. Following an enzymatic digestive pretreatment, we isolated a purified smooth muscle cell membrane fraction from saphenous veins in quantity sufficient to permit us to study the venous alpha 2-adrenoceptor content. The binding of tritiated rauwolscine was rapid, specific, saturable and reversible. The presence of high affinity binding sites (Kd = 1.53 +/- 0.71 nM) with a density of binding Bmax of 125.2 +/- 43.1 fmol/mg protein was demonstrated on a unique class of non interacting sites (nHill = 1.001 +/- 0.06). The kinetically derived Kd was 1.28 nM, in good agreement with the value obtained from saturation isotherms. The pharmacological profile of these sites was assessed by the comparison of the potency of alpha-adrenergic agonists and antagonists to inhibit 1 nM (3H)-rauwolscine. Their efficacy was respectively: rauwolscine greater than phentolamine greater than RX 781094 greater than clonidine much greater than prazosin greater than (-)-phenylephrine greater than (-)-noradrenaline. The results showed that (3H)-rauwolscine bound specifically to sites in our membranal preparation, which had the pharmacological characteristics of the alpha 2-adrenoceptors. The correlation between biochemical and pharmacological data revealed the usefulness of binding methods in the further study of adrenergic mechanisms in the canine saphenous vein.
使用高选择性α2 - 肾上腺素能拮抗剂萝芙辛作为氚标记配体，对犬隐静脉中的α2 - 肾上腺素能受体进行了生化研究。经过酶消化预处理后，我们从隐静脉中分离出了足够数量的纯化平滑肌细胞膜组分，足以让我们研究静脉α2 - 肾上腺素能受体的含量。氚标记萝芙辛的结合快速、特异、可饱和且可逆。在一类独特的非相互作用位点（nHill = 1.001 +/- 0.06）上，证明存在高亲和力结合位点（Kd = 1.53 +/- 0.71 nM），结合密度Bmax为125.2 +/- 43.1 fmol/mg蛋白质。动力学推导的Kd为1.28 nM，与从饱和等温线获得的值非常一致。通过比较α - 肾上腺素能激动剂和拮抗剂抑制1 nM（3H） - 萝芙辛的效力，评估了这些位点的药理学特征。它们的效力分别为：萝芙辛大于酚妥拉明大于RX 781094大于可乐定远大于哌唑嗪大于（ - ） - 去氧肾上腺素大于（ - ） - 去甲肾上腺素。结果表明，（3H） - 萝芙辛特异性结合我们膜制剂中的位点，这些位点具有α2 - 肾上腺素能受体的药理学特征。生化和药理学数据之间的相关性揭示了结合方法在进一步研究犬隐静脉肾上腺素能机制中的有用性。
