IN-VITRO EXCITATION OF PURIFIED MEMBRANE FRAGMENTS BY CHOLINERGIC AGONISTS .3. COMPARISON OF DOSE-RESPONSE CURVES TO DECAMETHONIUM WITH CORRESPONDING BINDING CURVES OF DECAMETHONIUM TO CHOLINERGIC RECEPTOR
IN-VITRO EXCITATION OF PURIFIED MEMBRANE FRAGMENTS BY CHOLINERGIC AGONISTS .3. COMPARISON OF DOSE-RESPONSE CURVES TO DECAMETHONIUM WITH CORRESPONDING BINDING CURVES OF DECAMETHONIUM TO CHOLINERGIC RECEPTOR
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DOI：
10.1007/bf01874114
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发表时间：
1971-01-01
影响因子：
2.4
通讯作者：
CHANGEUX, JP
中科院分区：
文献类型：
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作者：
KASAI, M;CHANGEUX, JP
通过超离心实验，将14c -十甲基铵（Deca）可逆地结合到从电虫的电组织中制备的可兴奋微囊上。α-Bungarotoxin是一种蛇毒毒素，可以不可逆地阻断14c - deca的结合。位移是偏的。被α-班加罗毒素取代的14c -Deca部分对应于与胆碱能受体位点结合的Deca分子，而在α-班加罗毒素存在下结合的14c -Deca部分对应于与乙酰胆碱酯酶（ache）催化位点结合的分子。发现胆碱能受体位点的总数与AcChE的催化位点的总数接近但不相同。在相同的微囊制备上，测量了14c -Deca的结合和对应于给定浓度Deca的渗透率响应，作为Deca浓度增加的函数。剂量-反应曲线与结合曲线几乎完全重合；换句话说，Deca的“表面”亲和力与其“实际”亲和力是一致的。14c - deca与管状立方碱的置换得到了与管状立方碱的“表观”亲和关系，这与它的“真实”亲和关系是一致的。估计了由一个Deca结合位点控制的离子载体的输运性质。
The reversible binding of14C-decamethonium (Deca) to excitable microsacs prepared from the electric tissue ofElectrophorus electricusis followed by an ultracentrifugal assay. α-Bungarotoxin, a snake venom toxin, blocks irreversibly the binding of14C-Deca. The displacement is partial. The fraction of14C-Deca displaced by α-bungarotoxin corresponds to molecules of Deca bound to the cholinergic receptor site, whereas the fraction of14C-Deca bound in the presence of α-bungarotoxin corresponds to molecules bound to the catalytic site of acetylcholinesterase (AcChE). The total number of cholinergic receptor sites is found to be close but not identical to the total number of catalytic sites of AcChE.On the same preparation of microsacs, the binding of14C-Deca and the permeability response corresponding to a given concentration of Deca are measured as a function of increased concentration of Deca. The dose-response curve and the binding curve superimpose almost exactly; in other words, the “apparent” affinity of Deca coincides with its “real” affinity. Displacement of14C-Deca byd-tubocurarine gives an “apparent” affinity ford-tubocurarine which coincides as well with its “real” affinity.The transport properties of the ionophore controlled by one Deca binding site are estimated.