Acetylcholine receptor: characterization of the voltage-dependent regulatory (inhibitory) site for acetylcholine in membrane vesicles from Torpedo californica electroplax.
Acetylcholine receptor: characterization of the voltage-dependent regulatory (inhibitory) site for acetylcholine in membrane vesicles from Torpedo californica electroplax.
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乙酰胆碱受体：来自加州鱼雷 electroplax 的膜囊泡中乙酰胆碱的电压依赖性调节（抑制）位点的表征。
作者：
K. Takeyasu;S. Shiono;J. Udgaonkar;N. Fujita;G. P. Hess
证据的烟碱乙酰胆碱受体上的乙酰胆碱结合的电压依赖性调节（抑制）网站获得的膜囊泡制备的电鳐californica电器官。两个速率系数，JA和α，这属于受体控制的离子通量，进行了测量。在pH 7.4、1 ℃的电压钳位条件下，在0至-48 mV的跨膜电压（Vm）范围内使用1000倍浓度范围的乙酰胆碱。提出了以下意见。(i)在低乙酰胆碱浓度下，JA的值，由受体的活性（非脱敏）状态的离子易位的速率系数，随着浓度的增加而增加。(ii)JA降低在高乙酰胆碱浓度。(iii)相反，α，受体脱敏的速率系数，没有显示出这样的下降。(iv)当囊泡膜的跨膜电位向更负的值变化时，（乙酰胆碱与调节位点结合的解离常数）对于Vm的25 mV变化降低约9倍，当KI（乙酰胆碱与控制通道开放的受体位点结合的解离常数）没有显示出这种变化，并且具有80 μ M的值。当Vm为-48 mV时，KR的值为8 μ M。(v)跨膜电压对调节位点的影响是可逆的，并且发生在测量中使用的猝灭流技术的时间分辨率（5 ms）内。（250字处删节）
Evidence for a voltage-dependent regulatory (inhibitory) site on the nicotinic acetylcholine receptor to which acetylcholine binds was obtained in membrane vesicles prepared from the Torpedo californica electric organ. Two rate coefficients, JA and alpha, which pertain to the receptor-controlled ion flux, were measured. A 1000-fold concentration range of acetylcholine was used in a transmembrane voltage (Vm) range from 0 to -48 mV under a voltage-clamped condition at pH 7.4, 1 degrees C. The following observations were made. (i) At low acetylcholine concentrations, the value of JA, the rate coefficient for ion translocation by the active (nondesensitized) state of the receptor, increased with increasing concentration. (ii) JA decreased at high acetylcholine concentrations. (iii) In contrast, alpha, the rate coefficient for receptor desensitization, did not show such a decrease. (iv) When the transmembrane potential of the vesicle membrane was changed to more negative values, the value of KR (the dissociation constant for binding of acetylcholine to the regulatory site) decreased by a factor of approximately 9 for a 25 mV change in Vm, while KI (the dissociation constant for binding of acetylcholine to the receptor site that controls channel opening) did not show such a change and has a value of 80 microM. When Vm is -48 mV, KR has a value of 8 microM. (v) The effect of a transmembrane voltage on the regulatory site was reversible and occurred within the time resolution (5 ms) of the quench-flow technique used in the measurements.(ABSTRACT TRUNCATED AT 250 WORDS)
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DOI：
10.1073/pnas.78.3.1361
发表时间：
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影响因子：
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发表时间：
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影响因子：
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影响因子：
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影响因子：
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作者：
Neubig,RR;Boyd,ND;Cohen,JB
通讯作者：
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一种方便的大规模分离可渗透特定无机离子的膜囊泡的方法：从电虫的电器官中分离和表征含有功能性乙酰胆碱受体的囊泡。
影响因子：
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作者：
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