Membrane Noise Analysis

  • Harold Lecar
  • Frederick Sachs


The fundamental units of excitability are membrane ionic channels. Excitation requires fast switches in membrane permeability, and these are effected by channels that are ion-selective and can be “gated” open and closed. A variety of experimental methods have contributed to establishing the present picture of discrete channels of molecular dimensions, each capable of carrying a rather high ion flux. In this chapter, we discuss an experimental method, membrane noise analysis, which allows one to estimate the ionic currents carried by individual channels. The reason gated ionic channels give rise to a special type of electrical noise is that channels can open and close at random under steadystate conditions. Because the ion flux through a single channel is relatively large, random channel transitions generate observable electrical current fluctuations. These characteristic current fluctuations, often called channel noise, can be distinguished from other types of electrical noise which may be generated in an excitable-cell preparation.


Voltage Clamp Channel Noise Current Noise Noise Analysis Current Fluctuation 
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Copyright information

© Plenum Press, New York 1981

Authors and Affiliations

  • Harold Lecar
    • 1
  • Frederick Sachs
    • 2
  1. 1.Laboratory of Biophysics, Intramural Research Program, National Institute of Neurological and Communicative Disorders and StrokeNational Institutes of HealthBethesdaUSA
  2. 2.Department of Pharmacology and TherapeuticsState University of New YorkBuffaloUSA

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