INFERENCES ABOUT MEMBRANE PROPERTIES FROM ELECTRICAL NOISE MEASUREMENTS
INFERENCES ABOUT MEMBRANE PROPERTIES FROM ELECTRICAL NOISE MEASUREMENTS
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DOI：
10.1016/s0006-3495(72)86141-1
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发表时间：
1972-01-01
影响因子：
3.4
通讯作者：
STEVENS, CF
中科院分区：
文献类型：
--
作者：
STEVENS, CF
生物膜中的电噪声的四个来源，每个具有不同的物理基础，进行了讨论;每种类型的噪声的分析可能会产生不同种类的膜特性的信息。(a)从热噪声谱中可以得到无源膜阻抗，从而使热噪声测量基本上等同于科尔和柯蒂斯进行的自波分析。(b)如果可以进行足够高的频率测量，热噪声谱应该给出膜内单个离子的平均运动信息。(c)膜内的电荷载流子的数量和单个离子的迁移率可以从噪声的a1/f spectrum.Available的数据表明，例如，轴突膜电导的增加是不通过膜内离子迁移率的调制来实现的。(d)由通常负责膜电导变化的机制引起的波动可以产生一种类型的电噪声。这种电导波动的分析提供了一种方法来评估各个通道行为的各种微观模型的有效性。两种不同的概率解释的霍奇金-赫胥黎方程在这里进行了研究，并产生不同的预测电导波动的频谱，因此，适当的噪声测量可能有助于消除某些类别的微观模型膜电导的变化。此外，它示出了如何电导波动的分析，在某些情况下，可以提供一个单一的通道的电导的估计。
Four sources of electrical noise in biological membranes, each with a different physical basis, are discussed; the analysis of each type of noise potentially yields a different sort of information about membrane properties. (a) From thethermal noise spectrum,the passive membrane impedance may be obtained, so that thermal noise measurements are essentially equivalent to the type of since wave analysis carried out by Cole and Curtis. (b) If adequately high frequency measurements could be made, theshot noise spectrumshould give information about the average motion of a single ion within the membrane. (c) The number of charge carriers and single ion mobilities within the membrane can possibly be inferred from measurements of noise with a1/f spectrum.Available data indicate, for example, that increases in axon membrane conductance are not achieved by modulations in the mobility of ions within the membrane. (d) Fluctuations arising from the mechanisms normally responsible for membrane conductance changes can produce a type of electrical noise. Analysis of suchconductance fluctuationsprovides a way to assess the validity of various microscopic models for the behavior of individual channels. Two different probabilistic interpretations of the Hodgkin-Huxley equations are investigated here and shown to yield different predictions about the spectrum of conductance fluctuations; thus, appropriate noise measurements may serve to eliminate certain classes of microscopic models for membrane conductance changes. Further, it is shown how the analysis of conductance fluctuations can, in some circumstances, provide an estimate of the conductance of a single channel.