Counting channels: A tutorial guide on ion channel fluctuation analysis
Counting channels: A tutorial guide on ion channel fluctuation analysis
复制标题
DOI：
10.1152/advan.00006.2002
复制
发表时间：
2002-12-01
影响因子：
2.1
通讯作者：
Latorre, R
中科院分区：
文献类型：
--
作者：
Alvarez, O;Gonzalez, C;Latorre, R
根据概率定律，频道以随机的方式打开和关闭。然而，与掷硬币或掷骰子不同，发现通道关闭或打开的概率不是一个固定的数字，而是可以通过一些外部刺激来修改(即，我们可以作弊)，例如电压。可以使用适当的电生理技术(例如，膜片钳)获得单通道记录，并且可以从这些记录计算开放概率和通道电导。从包含多个通道的膜收集这些参数并不简单，因为宏观电流i=INp(O)，其中i是单通道电流，N是通道数量，P-o是发现通道打开的概率，不能被分成其单独的分量。在本教程中，利用离子通道的概率性质，我们详细讨论如何使用波动(非平稳噪声)分析(Sigworth FJ)获得I、N和P-o(Max)(最大开放概率)。G Gen Physiol307：97-129,1980)。我们还分析了在确定I和N时可能存在的伪影的来源，例如通道损耗、不充分的滤波以及使用模拟计算机程序(可在www.cecs.cl上获得)进行数字数据采集的有限分辨率。
I on channels open and close in a stochastic fashion, following the laws of probability. However, distinct from tossing a coin or a die, the probability of finding the channel closed or open is not a fixed number but can be modified (i.e., we can cheat) by some external stimulus, such as the voltage. Single-channel records can be obtained using the appropriate electrophysiological technique (e.g., patch clamp), and from these records the open probability and the channel conductance can be calculated. Gathering these parameters from a membrane containing many channels is not straightforward, as the macroscopic current I = iNP(o), where i is the single-channel current, N the number of channels, and P-o the probability of finding the channel open, cannot be split into its individual components. In this tutorial, using the probabilistic nature of ion channels, we discuss in detail how i, N, and P-o (max) (the maximum open probability) can be obtained using fluctuation (nonstationary noise) analysis (Sigworth FJ. G Gen Physiol 307: 97-129, 1980). We also analyze the sources of possible artifacts in the determination of i and N, such as channel rundown, inadequate filtering, and limited resolution of digital data acquisition by use of a simulation computer program (available at www.cecs.cl).