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. 1973 Mar;70(3):876–879. doi: 10.1073/pnas.70.3.876

Relaxation Spectra of Potassium Channel Noise from Squid Axon Membranes

Harvey M Fishman 1,2
PMCID: PMC433379  PMID: 4514998

Abstract

Power density spectra of electrical fluctuations in potential and current (during voltage clamp) in the steady state, measured from electrically isolated patches of squid axon membrane, contain a noise component that is of the form [1 + (f/fc)2]-1. For potential and temperature changes fc = (2πτn)-1, where τn is the Hodgkin-Huxley relaxation time for the potassium channel. These and other data strongly suggest that this noise is due to the potassium ion passage process in the membrane. Furthermore, by comparison of the values of fc from relaxation spectra of membrane channel noise with those from calculated (Hodgkin-Huxley equations) power spectra, it is possible to relate and compare channel models that previously could only be applied to macroscopic potassium conductance data. An initial result of this comparison suggests that a two-state (open-closed) conductance model, which is based upon a literal interpretation of the Hodgkin-Huxley equations, is not likely to be correct.

Keywords: fluctuation phenomena, conductance models, membrane patch, ion permeation

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ARMSTRONG C. M., BINSTOCK L. ANOMALOUS RECTIFICATION IN THE SQUID GIANT AXON INJECTED WITH TETRAETHYLAMMONIUM CHLORIDE. J Gen Physiol. 1965 May;48:859–872. doi: 10.1085/jgp.48.5.859. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bezanilla F., Armstrong C. M. Negative conductance caused by entry of sodium and cesium ions into the potassium channels of squid axons. J Gen Physiol. 1972 Nov;60(5):588–608. doi: 10.1085/jgp.60.5.588. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Brinley F. J., Jr, Mullins L. J. Sodium extrusion by internally dialyzed squid axons. J Gen Physiol. 1967 Nov;50(10):2303–2331. doi: 10.1085/jgp.50.10.2303. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. COLE K. S., MOORE J. W. Potassium ion current in the squid giant axon: dynamic characteristic. Biophys J. 1960 Sep;1:1–14. doi: 10.1016/s0006-3495(60)86871-3. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Canessa-Fischer M., Zambrano F., Rojas E. The loss and recovery of the sodium pump in perfused giant axons. J Gen Physiol. 1968 May;51(5 Suppl):162S+–162S+. [PubMed] [Google Scholar]
  6. Chandler W. K., Meves H. Voltage clamp experiments on internally perfused giant axons. J Physiol. 1965 Oct;180(4):788–820. doi: 10.1113/jphysiol.1965.sp007732. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Derksen H. E., Verveen A. A. Fluctuations of resting neural membrane potential. Science. 1966 Mar 18;151(3716):1388–1389. doi: 10.1126/science.151.3716.1388. [DOI] [PubMed] [Google Scholar]
  8. Fishman H. M. Direct and rapid description of the individual ionic currents of squid axon membrane by ramp potential control. Biophys J. 1970 Sep;10(9):799–817. doi: 10.1016/S0006-3495(70)86336-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. HODGKIN A. L., HUXLEY A. F. A quantitative description of membrane current and its application to conduction and excitation in nerve. J Physiol. 1952 Aug;117(4):500–544. doi: 10.1113/jphysiol.1952.sp004764. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hill T. L., Chen Y. D. On the theory of ion transport across the nerve membrane. IV. Noise from the open-close kinetics of K + channels. Biophys J. 1972 Aug;12(8):948–959. doi: 10.1016/S0006-3495(72)86136-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Moore J. W., Narahashi T. Tetrodotoxin's highly selective blockage of an ionic channel. Fed Proc. 1967 Nov-Dec;26(6):1655–1663. [PubMed] [Google Scholar]
  12. Poussart D. J. Membrane current noise in lobster axon under voltage clamp. Biophys J. 1971 Feb;11(2):211–234. doi: 10.1016/S0006-3495(71)86209-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Stevens C. F. Inferences about membrane properties from electrical noise measurements. Biophys J. 1972 Aug;12(8):1028–1047. doi: 10.1016/S0006-3495(72)86141-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. TASAKI I., HAGIWAR A. S. Demonstration of two stable potential states in the squid giant axon under tetraethylammonium chloride. J Gen Physiol. 1957 Jul 20;40(6):859–885. doi: 10.1085/jgp.40.6.859. [DOI] [PMC free article] [PubMed] [Google Scholar]

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