STEREOSPECIFIC BINDING AS A TOOL IN ATTEMPTS TO LOCALIZE AND ISOLATE MUSCARINIC RECEPTORS .2. BINDING OF (+)-BENZETIMIDE, (-)-BENZETIMIDE AND ATROPINE TO A FRACTION FROM BOVINE TRACHEAL SMOOTH-MUSCLE AND TO BOVINE CAUDATE-NUCLEUS
STEREOSPECIFIC BINDING AS A TOOL IN ATTEMPTS TO LOCALIZE AND ISOLATE MUSCARINIC RECEPTORS .2. BINDING OF (+)-BENZETIMIDE, (-)-BENZETIMIDE AND ATROPINE TO A FRACTION FROM BOVINE TRACHEAL SMOOTH-MUSCLE AND TO BOVINE CAUDATE-NUCLEUS
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DOI：
10.1016/0014-2999(74)90051-x
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发表时间：
1974-01-01
影响因子：
5
通讯作者：
ARIENS, EJ
中科院分区：
文献类型：
--
作者：
BELD, AJ;ARIENS, EJ
用平衡透析法研究了抗胆碱能剂（±）-苯并胺和阿托品-3的活性对映体(+)-苯并胺- h3和(−)-苯并胺- h3与牛气管平滑肌的浓度依赖性结合。结合曲线分析显示(+)-苯并咪胺和阿托品存在可饱和的高亲和力结合位点，但(−)-苯并咪胺不存在。结合的立体特异性以及与胆碱能和非胆碱能化合物的竞争实验结果证明，(+)-苯并胺和阿托品的高亲和力结合位点与毒蕈碱受体相同。尝试用洗涤剂溶解结合位点，通常用于这类工作，导致完全失去立体特异性。洋地黄苷是一种具有温和洗涤性能的植物苷，其释放的组分与(+)-苯并胺- h3和(−)-苯并胺- h3的结合方式仍然不同，这强烈表明存在溶解的毒蕈碱受体。在尾状核中观察到的抗胆碱能药物的立体选择性结合位点也可以用洋地黄苷溶解，但只有在用己烷提取冻干匀浆后才能溶解。
The concentration-dependent binding of (+)-benzetimide-H3and (−)-benzetimide-H3, the active and inactive enantiomers, respectively of the anticholinergic agent, (±)-benzetimide, and of atropine-3to a fraction from bovine tracheal smooth muscle was studied by equilibrium dialysis. Analysis of the binding curves revealed the presence of a saturable high affinity binding site for (+)-benzetimide and atropine but not for (−)-benzetimide. The stereospecificity of the binding and the results of competition experiments with cholinergic and non-cholinergic compounds provided evidence, that the high affinity binding sites for (+)-benzetimide and atropine are identical with the muscarinic receptor. Attempts to solubilize the binding sites with detergents, commonly used in this type of work, resulted in complete loss of stereospecificity. Digitonin, a plant glycoside with mild detergent properties, released components to which (+)-benzetimide-H3and (−)-benzetimide-H3were still bound differently, strongly suggesting the presence of solubilized muscarinic receptors. The stereoselective binding sites for anticholinergic agents, as observed in the caudate nucleus, could also be solubilized with digitonin but only after hexane extraction of lyophilized homogenates.