Ionic selectivity, saturation, and block in sodium channels. A four-barrier model.
نویسندگان
چکیده
منابع مشابه
Ionic selectivity, saturation, and block in sodium channels. A four- barrier model
Ionic fluxes in Na channels of myelinated axons show ionic competition, block, and deviations from simple flux independence. These phenomena are particularly evident when external Na+ ions are replaced by other permeant or impermeant ions. The observed currents require new flux equations not based on the concepts of free diffusion. A specific permeability model for the Na channel is developed f...
متن کاملIonic Selectivity, Saturation, and Block in Sodium Channels
A B S TR ACT Ionic fluxes in Na channels of myelinated axons show ionic competition, block, and deviations from simple flux independence. These phenomena are particularly evident when external Na + ions are replaced by other permeant or impermeant ions. The observed currents require new flux equations not based on the concepts of free diffusion. A specific permeability model for the Na channel ...
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The open-channel conductance properties of a voltage-gated channel from sarcoplasmic reticulum were studied in planar phospholipid membranes. The channel is ideally selective for K+ over Cl- and for K+ over Ca++. In symmetrical 1 M solutions, the single-channel conductance (in pmho) falls in the order: K+ (214) > NH4+ (157) > Rb+ (125) > Na+ (72) > La+ (8.1) > Cs+ (< 3). In neutral bilayers, th...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1975
ISSN: 0022-1295,1540-7748
DOI: 10.1085/jgp.66.5.535