Empirical considerations regarding the use of ensemble-variance analysis of macroscopic currents
Empirical considerations regarding the use of ensemble-variance analysis of macroscopic currents
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DOI：
10.1016/j.jneumeth.2006.05.027
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发表时间：
2006-11-15
影响因子：
3
通讯作者：
Lingle, Christopher J.
中科院分区：
文献类型：
--
作者：
Lingle, Christopher J.
离子通道的两个基本特性是它的单通道电流(i)和它的打开概率（P(o)），它们是由单通道记录最直接定义的。然而，在某些情况下，实际限制（例如，极端电压）或独特的通道属性可能会阻止使用单通道记录来定义此类属性。作为替代方案，宏观电流的方差（非平稳噪声分析或方差均值分析）已被用来定义底层通道的基本基本特性。尽管其他人在之前的工作中已经考虑了方差-均值方法的一些局限性，但这里使用模拟方法来定义方差分析适合提供i和P(o)估计的条件。特别令人感兴趣的是，即使在P(o)小于0.5的条件下，P(o)的合理可靠估计可以得到的程度。从经验上看，分析表明，有足够的扫描次数和对i的初始估计的限制，可以将P(o)的合理可靠估计降低到0.2。还考虑了许多其他因素对方差均值分析效用的影响，包括失活、过滤和特定门控方案的后果的影响。(c) 2006 Elsevier B.V.版权所有
Two fundamental properties of an ion channel are its single channel current (i) and its open probability (P(o)), which are most directly defined by single channel recordings. However, under some circumstances either practical limitations (e.g., extreme voltages) or unique channel properties may preclude the use of single channel recordings for definition of such properties. As an alternative, the variance in macroscopic currents (non-stationary noise analysis or variance-mean analysis) has been exploited to define fundamental elementary properties of the underlying channels. Although some limitations of the variance-mean approach have been considered in previous work by others, here simulation methods were used to define the conditions under which variance analysis can be suitable for providing estimates of i and P(o). Of particular interest is the extent to which reasonably reliable estimates of P(o) can be obtained, even under conditions of P(o) less than 0.5. Empirically, the analysis indicates that, with sufficient numbers of sweeps and with constraints on initial estimates of i, reasonably reliable estimates of P(o) can be made down to 0.2. The impact of a number of other factors on the utility of variance-mean analysis are also considered, including effects of inactivation, filtering, and the consequences of particular gating schemes. (c) 2006 Elsevier B.V. All rights reserved.