Miller J H, Gibson V A, McKinney M
Department of Pharmacology, Mayo Clinic Jacksonville, Florida.
J Pharmacol Exp Ther. 1991 Nov;259(2):601-7.
The binding selectivity of [3H]AF-DX 384 [(+-)-5,11-dihydro-11- ([(2-(2-[(dipropylamino)methyl]-1- piperidinyl)ethyl)amino]carbonyl)-H-pyrido(2,3-b)(1,4)benzodiazepine-6-o ne] was evaluated with cloned human muscarinic receptors (M1-M4) in Chinese hamster ovary (CHO-K1) cell lines as well as in rat heart and brain. There were uniform classes of sites for the radioligand in the M2-rich tissues, heart (Kd = 2.3 nM) and brainstem (Kd = 2.4 nM). However, [3H]AF-DX 384 bound to all four cloned receptor subtypes. Using kinetic methods, the calculated Kd values were M2 (1 nm) greater than M4 (2.2 nM) greater than M3 (15 nM) greater than M1 (55 nM). Scatchard analysis with the CHO cells confirmed the high affinity of this radioligand for the M2 (1.8 nM) and M4 (2.5 nM) receptors. To evaluate the potential for selectively binding to M2 and M4 receptors in cortex and striatum, low concentrations (0.5-0.8 nM) of the radioligand were used and a two-site competition model was used to derive the binding constants for pirenzepine and AF-DX 116 [(+-)-11-2((-((diethylamino) methyl)-1-piperidinyl)acetyl)-5,11-dihydro-6H- pyrido(2,3-b)(1,4)-benzodiazepine-6-one] and to compare them with values obtained with cloned M2 and M4 receptors.(ABSTRACT TRUNCATED AT 250 WORDS)
利用中国仓鼠卵巢（CHO-K1）细胞系中的克隆人毒蕈碱受体（M1-M4）以及大鼠心脏和大脑，评估了[3H]AF-DX 384[（±）-5,11-二氢-11-（[（2-（2-[(二丙基氨基)甲基]-1-哌啶基）乙基]氨基）羰基]-H-吡啶并(2,3-b)(1,4)苯二氮䓬-6-酮]的结合选择性。在富含M2的组织、心脏（Kd = 2.3 nM）和脑干（Kd = 2.4 nM）中，放射性配体存在统一的位点类别。然而，[3H]AF-DX 384与所有四种克隆受体亚型均有结合。采用动力学方法，计算得到的Kd值为M2（1 nM）大于M4（2.2 nM）大于M3（15 nM）大于M1（55 nM）。对CHO细胞进行的Scatchard分析证实了该放射性配体对M2（1.8 nM）和M4（2.5 nM）受体具有高亲和力。为评估在皮质和纹状体中选择性结合M2和M4受体的潜力，使用了低浓度（0.5 - 0.8 nM）的放射性配体，并采用双位点竞争模型来推导哌仑西平和AF-DX 116[（±）-11-2（-（（二乙氨基）甲基）-1-哌啶基）乙酰基]-5,11-二氢-6H-吡啶并(2,3-b)(1,4)-苯二氮䓬-6-酮]的结合常数，并将其与克隆的M2和M4受体得到的值进行比较。（摘要截短于250字）
