Muscarinic Cholinergic Receptor Binding in the Longitudinal Muscle of the Guinea Pig Ileum with [3H]Quinuclidinyl Benzilate
Muscarinic Cholinergic Receptor Binding in the Longitudinal Muscle of the Guinea Pig Ileum with [3H]Quinuclidinyl Benzilate
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[3H]Quinuclidinyl Benzilate 与豚鼠回肠纵向肌中的毒蕈碱胆碱能受体结合
DOI：
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发表时间：
1974
期刊：
影响因子：
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通讯作者：
S. Snyder
中科院分区：
文献类型：
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作者：
H. Yamamura;S. Snyder
豚鼠回肠纵行肌匀浆与[~3H]奎宁基苯甲酸酯(QNB)的结合表现为与M胆碱能受体的几乎排他性相互作用。QNB与这些制剂中的颗粒物质以可饱和的方式结合在一起。多种M受体拮抗剂和激动剂在抑制豚鼠回肠中M受体亲和力的同时，也抑制了特异性的[~3H]QNB结合。许多烟碱型胆碱能和非胆碱能药物对[~3H]QNB结合部位的亲和力可以忽略不计。由[~3H]QNB饱和实验和QNB抑制实验估算的QNB-受体复合体在25°时的离解常数约为0.3-0.5 nm。测得缔合(4×108M-1min-1)和解离(1.2×10-2min-1)的双分子速率常数分别为35°和0.03 nm。[~3H]QNB的最大特异性结合表明受体的浓度约为190pmoles/g组织。在豚鼠的脾、心和肺中也可以发现[~3H]QNB的特异性结合，而在豚鼠的横隔膜、肾脏和肝脏中则没有。
The binding of [3H]quinuclidinyl benzilate (QNB) to homogenates of the longitudinal muscle of guinea pig ileum appears to represent an almost exclusive interaction with muscarinic cholinergic receptor sites. [3H]QNB binds to particulate matter in these preparations in a saturable fashion with respect to [3H]QNB. A variety of muscarinic antagonists and agonists inhibit specific [3H]QNB binding in parallel with their estimated affinity for muscarinic receptors in the guinea pig ileum, based on pharmacological procedures. Numerous nicotinic cholinergic and noncholinergic drugs have negligible affinity for [3H]QNB binding sites. The dissociation constant of the QNB-receptor complex estimated from saturation experiments with [3H]QNB and from inhibition experiments with QNB is about 0.3-0.5 nM at 25°. The bimolecular rate constant of association (4 x 108 M-1 min-1) and dissociation (1.2 x 10-2 min-1) were estimated at 35° and indicate a dissociation constant of 0.03 nM. The maximal specific binding of [3H]QNB indicates a concentration of receptors of about 190 pmoles/g of tissue. Specific [3H]QNB binding can also be demonstrated in guinea pig spleen, heart, and lung, but not in guinea pig diaphragm, kidney, or liver.