[3H]Quinuclidinyl benzilate binding to muscarinic receptors and [3H]WB-4101 binding to alpha-adrenergic receptors in rabbit iris. Comparison of results in slices and microsomal fractions.
[3H]Quinuclidinyl benzilate binding to muscarinic receptors and [3H]WB-4101 binding to alpha-adrenergic receptors in rabbit iris. Comparison of results in slices and microsomal fractions.
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[3H]苯甲酸奎宁环酯与毒蕈碱受体结合，[3H]WB-4101与兔虹膜中的α-肾上腺素受体结合。
DOI：
10.1016/0006-2952(80)90001-5
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发表时间：
1980
影响因子：
5.8
通讯作者：
Akhtar,RA
中科院分区：
文献类型：
--
作者：
TaftJr,WC;Abdel-Latif,AA;Akhtar,RA
比较了[~3H]-(L)-苯甲酸奎宁酯和[~3H]-WB-4101与兔虹膜肌微粒体的结合特性。[~3H]QNB与微粒体组分和肌肉切片的结合具有高亲和力和低容量，并被M胆碱配体取代。[~3H]QNb与微粒子和切片的平衡解离常数(Kd)分别为0.069 nM和1.97 nM。在结合速率常数(Ki)和抑制常数(Kj)中也观察到微体部分的Kp值比切片的Kp值更高，但对解离速率常数(K−1)没有观察到这种变化。对[~3H]WB-4101结合特性的动力学研究表明，微粒体组分和切片的KD值分别为2.33和10.19 nm，具有高亲和力。[~H]QNB和[~H]WB-4101与微粒体组分和完整肌肉切片结合的类似结合模式的发现反对组织破坏后受体属性发生变化的可能性。有人认为，在完整组织和无细胞匀浆之间出现的受体介导的生化反应的差异，如磷脂酰肌醇效应，更有可能是由于受体功能的变化，例如离子通透性的变化，而不是受体性质的实际变化。
The binding characteristics of [3H]-(l)-quinuclidinyl benzilate (QNB) and [3H]WB-4101 to microsomal fractions and slices from rabbit iris muscle were compared. [3H] QNB binding to both microsomal fractions and muscle slices was of high affinity and low capacity and was displaced by muscarinic ligands. The equilibrium dissociation constants (KD) for [3H]QNB binding to microsomes and slices were 0.069 nM and 1.97nM, respectively. This shift to a higher value for theKpof the microsomal fraction compared with that of the slices was also observed lor the association rate constants (KI) and inhibition constants (KJ), but not for the dissociation rate constants (K−1). Kinetic studies on the binding characteristics of [3H]WB-4101 revealed high affinity sites withKDvalues of 2.33 and 10.19 nM for microsomal fractions and slices, respectively. The findings of comparable binding patterns for [3H]QNB and [3H]WB-4101 binding to microsomal fractions and intact muscle slices argue against the possibility of alterations in receptor properties following tissue disruption. It is proposed that the differences in receptor-mediated biochemical responses that are seen between intact tissue and cell-free homogenates, such as the ‘phosphoinositide effect’, are more likely to be due to alterations in receptor function, e.g. changes in ionic permeabilities, rather than to actual changes in receptor properties.