André C, Marullo S, Convents A, Lü B Z, Guillet J G, Hoebeke J, Strosberg D A
Laboratoire de Biochimie Cellulaire, Collège de France, Paris.
Eur J Biochem. 1988 Jan 15;171(1-2):401-7. doi: 10.1111/j.1432-1033.1988.tb13804.x.
Binding studies with the radiolabeled muscarinic antagonists dexetimide, quinuclidinyl benzilate and N-methylscopolamine showed that the human embryonic lung fibroblast CCL137 possesses approximately 2 X 10(5) muscarinic receptors/cell, i.e. 2.1 pmol/mg membrane protein. These receptors showed a marked stereoselectivity towards dexetimide and levetimide and only low affinity for another antagonist, pirenzepine. The muscarinic agonist carbamylcholine inhibited forskolin-stimulated adenylate cyclase and induced phosphatidylinositide turnover in the intact cells. Both effects were inhibited by the muscarinic antagonist atropine. Affinity labeling with tritiated propylbenzylcholine mustard revealed a protein of 72 kDa. Finally, down-regulation of the membrane receptors following prolonged treatment with the agonist carbamylcholine was assessed by means of the hydrophilic antagonist N-methylscopolamine.
用放射性标记的毒蕈碱拮抗剂右苯丙胺、樟柳碱和N-甲基东莨菪碱进行的结合研究表明，人胚胎肺成纤维细胞CCL137约有2×10⁵个毒蕈碱受体/细胞，即2.1 pmol/mg膜蛋白。这些受体对右苯丙胺和左苯丙胺表现出明显的立体选择性，而对另一种拮抗剂哌仑西平的亲和力较低。毒蕈碱激动剂氨甲酰胆碱抑制福斯高林刺激的腺苷酸环化酶，并诱导完整细胞中的磷脂酰肌醇周转。这两种效应均被毒蕈碱拮抗剂阿托品抑制。用氚化丙基苄基胆碱芥进行亲和标记，显示出一种72 kDa的蛋白质。最后，通过亲水性拮抗剂N-甲基东莨菪碱评估用激动剂氨甲酰胆碱长期处理后膜受体的下调情况。
