Blocker-related changes of channel density. Analysis of a three-state model for apical Na channels of frog skin
Blocker-related changes of channel density. Analysis of a three-state model for apical Na channels of frog skin
复制标题
通道密度与阻断剂相关的变化。
DOI：
--
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Lynn M. Baxendale
中科院分区：
文献类型：
--
作者：
S. I. Helman;Lynn M. Baxendale
用电中性阻断剂（CDPC，6-氯-3，5-二氨基-吡嗪-2-甲酰胺）进行蛙皮肤上皮细胞的顶膜Na通道的阻断剂诱导的噪声分析，所述电中性阻断剂允许测定单通道Na电流和通道密度的变化，同时对Na转运的宏观速率具有最小的抑制作用（Eschendale，L. M.，和S. I.赫尔曼1986. Biophys.《约》49：160 a）。实验的目的是解决由于质量定律的作用（因此与钠通道的阻滞剂相互作用的动力学方案）和钠通道密度的自动调节，发生作为抑制钠转运的结果通道密度的变化。通道密度的质量定律作用变化符合封闭、开放和阻断状态的动力学方案，其中阻断剂主要与开放通道相互作用。这种行为在“脉冲”方案实验中观察得最好，该实验最大限度地减少了暴露于阻断剂的时间，从而最大限度地减少了时间常数更长的自动调节对通道密度的影响。来自脉冲，阶梯，和其他实验方案使用CDPC和阿米洛利作为噪声诱导阻断剂和解释的三态模型的背景下的数据分析显示，钠通道开放概率在没有阻断剂的情况下平均接近0.5，在0.1和0.9之间的组织之间的宽范围。
Blocker-induced noise analysis of apical membrane Na channels of epithelia of frog skin was carried out with the electroneutral blocker (CDPC, 6-chloro-3,5-diamino-pyrazine-2-carboxamide) that permitted determination of the changes of single-channel Na currents and channel densities with minimal inhibition of the macroscopic rates of Na transport (Baxendale, L. M., and S. I. Helman. 1986. Biophys. J. 49:160a). Experiments were designed to resolve changes of channel densities due to mass law action (and hence the kinetic scheme of blocker interaction with the Na channel) and to autoregulation of Na channel densities that occur as a consequence of inhibition of Na transport. Mass law action changes of channel densities conformed to a kinetic scheme of closed, open, and blocked states where blocker interacts predominantly if not solely with open channels. Such behavior was best observed in "pulse" protocol experiments that minimized the time of exposure to blocker and thus minimized the contribution of much longer time constant autoregulatory influences on channel densities. Analysis of data derived from pulse, staircase, and other experimental protocols using both CDPC and amiloride as noise-inducing blockers and interpreted within the context of a three-state model revealed that Na channel open probability in the absence of blocker averaged near 0.5 with a wide range among tissues between 0.1 and 0.9.
DOI：
10.1073/pnas.83.8.2767
发表时间：
1986-04-01
影响因子：
11.1
作者：
PALMER, LG;FRINDT, G
通讯作者：
FRINDT, G