Block of neuronal fast chloride channels by internal tetraethylammonium ions.
Block of neuronal fast chloride channels by internal tetraethylammonium ions.
复制标题
神经元快速氯化物通道的块由四乙基铵离子内部。
DOI：
10.1085/jgp.104.1.173
复制
发表时间：
1994-07
影响因子：
3.8
通讯作者：
BLATZ, AL
中科院分区：
文献类型：
--
作者：
SANCHEZ, DY;BLATZ, AL
当将经典的钾选择性离子通道阻断剂四乙铵离子（TEA）应用于先前的细胞内膜表面时，可以阻断急性分离的大鼠皮质神经元切除的表面膜上的氯选择性离子通道。在 TEAi 存在的情况下，使用贴片电压钳方法记录来自快速 Cl 通道的单通道电流。在使用的滤波截止频率（3-12.4 kHz，-3 dB）下，TEAi 引起的阻断表现为单通道电流幅度的降低，这被解释为阻断反应的解离速率极快的结果。在这些实验条件下，TEAi 阻断的大小与膜电位无关。剂量反应实验结果分析表明，TEA 结合导致这些通道部分阻断，平衡解离常数约为 12-15 mM。使用 Yellen 的方法（1994. Journal of General Physiology. 84:157-186.）对不存在和存在 TEAi 时的振幅分布进行分析，产生了类似的平衡解离常数，并提供了大约 16,000 mM-1.s-1 的阻断速率常数和大约 200,000 s-1 的解阻断速率常数。开放和封闭间隔持续时间的分布符合阻塞方案，其中 TEAi 与开放动力学状态结合，并限制通道必须在 TEA 解离之前重新进入开放状态。该模型可以很好地拟合开放状态平均寿命的增加，但闭区间持续时间的分布却不能，这表明存在更复杂的底层阻塞机制。
The classical potassium-selective ion channel blocker tetraethylammonium ion (TEA) was shown to block chloride-selective ion channels from excised surface membranes of acutely dissociated rat cortical neurons when applied to the formerly intracellular membrane surface. The patch voltage clamp method was used to record single channel currents from fast Cl channels in the presence of TEAi. At the filtering cut-off frequencies used (3-12.4 kHz, -3 dB) the TEAi-induced block appeared as a reduction in single channel current amplitude, which was interpreted as the result of extremely fast on the off rates for the blocking reaction. Under the conditions of these experiments, the magnitude of TEAi block was independent of membrane potential. Analysis of dose-response experimental results suggests that TEA binding resulted in a partial block of these channels with an equilibrium dissociation constant of approximately 12-15 mM. Analysis of amplitude distributions in the absence and presence of TEAi using the method of Yellen (1994. Journal of General Physiology. 84:157-186.) produced a similar equilibrium dissociation constant and provided a blocking rate constant of approximately 16,000 mM-1.s-1 and an unblocking rate constant of approximately 200,000 s-1. The distributions of open and closed interval durations were fit with a blocking scheme where TEAi binds to the open kinetic state with the constraint that the channel must reenter the open state before TEA can dissociate. The increase in the mean lifetime of the open state could be well fit by this model, but the distribution of closed interval durations could not, suggesting a more complex underlying blocking mechanism.
登录
查看更多内容
DOI：
10.1085/jgp.59.4.388
发表时间：
1972-04
期刊：
The Journal of general physiology
影响因子：
--
作者：
Armstrong CM;Hille B
通讯作者：
Hille B
影响因子：
56.9
作者：
MACKINNON, R;YELLEN, G
通讯作者：
YELLEN, G
影响因子：
16.2
作者：
NEWLAND, CF;ADELMAN, JP;ALMERS, W
通讯作者：
ALMERS, W
影响因子：
56.9
作者：
HARTMANN, HA;KIRSCH, GE;BROWN, AM
通讯作者：
BROWN, AM
DOI：
10.1085/jgp.85.5.669
发表时间：
1985-05
期刊：
The Journal of general physiology
影响因子：
--
作者：
French RJ;Shoukimas JJ
通讯作者：
Shoukimas JJ