Potassium-Ion conduction noise in squid axon membrane
- 1 December 1975
- journal article
- Published by Springer Science and Business Media LLC in The Journal of Membrane Biology
- Vol. 24 (1), 305-328
- https://doi.org/10.1007/bf01868629
Abstract
Spectral analysis (1–1000 Hz) of spontaneous fluctuations of potential and current in small areas of squid (Loligo pealei) axon shows two forms of noise:f −1 noise occurs in both excitable and inexcitable axons with an intensity which depends upon the driving force for potassium ions. The other noise has a spectral form corresponding to a relaxation process, i.e., its asymptotic behavior at low frequencies is constant, and at high frequencies it declines with a slope of −2. This latter noise occurs only in excitable axons and was identified in spectra by (1) its disappearance after reduction of K+ current by internal perfusion with solutions containing tetraethylammonium (TEA+), Cs+ or reduced [K i + ] and (2) its insensitivity to block of Na+ conduction and active transport. The transition frequency of relaxation spectra are also voltage and temperature dependent and relate to the kinetics of K+ conduction in the Hodgkin-Huxley formulation. These data strongly suggest that the relaxation noise component arises from the kinetic properties of K+ channels. Thef −1 noise is attributed to restricted diffusion in conducting K+ channels and/or leakage pathways. In addition, an induced K+-conduction noise associated with the binding of TEA+ and triethyldecylammonium ion to membrane sites is described. Measurement of the induced noise may provide an alternative means of characterizing the kinetics of interaction of these molecules with the membrane and also suggests that these and other pharmacological agents may not be useful in identifying noise components related to the sodium conduction mechanism which, in these experiments, appears to be much lower in intensity than either the normal K conduction or induced noise components.Keywords
This publication has 30 references indexed in Scilit:
- Excess electrical noise during current flow through porous membranes separating ionic solutionsThe Journal of Membrane Biology, 1975
- Noise measurements in squid axon membraneThe Journal of Membrane Biology, 1975
- Patch voltage clamp of squid axon membraneThe Journal of Membrane Biology, 1975
- The nature of the voltage-dependent conductance induced by alamethicin in black lipid membranesThe Journal of Membrane Biology, 1973
- Electrical noise from synthetic membranesThe Journal of Membrane Biology, 1972
- Negative Conductance Caused by Entry of Sodium and Cesium Ions into the Potassium Channels of Squid AxonsThe Journal of general physiology, 1972
- Membrane Noise produced by AcetylcholineNature, 1970
- The Nature of the Negative Resistance in Bimolecular Lipid Membranes Containing Excitability-Inducing MaterialThe Journal of general physiology, 1970
- Fluctuations of Resting Neural Membrane PotentialScience, 1966
- Anomalous Rectification in the Squid Giant Axon Injected with Tetraethylammonium ChlorideThe Journal of general physiology, 1965