Gating current in the membrane of nodes of Ranvier under conditions of linear alteration of the membrane potential

Asymmetrical displacement currents (Id) in the frog Ranvier node (R. ridibunda) treated with tetrodotoxin and tetraethylammonium were studied by the use of ramp-voltage pulses. In some experiments both ramp- and step-voltage pulses were used. The net Id consists of two components, one of which Id (I...

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Bibliographic Details
Published inBiulleten' eksperimental'noi biologii i meditsiny Vol. 84; no. 11; p. 515
Main Authors Peganov, E M, Khodorov, B I
Format Journal Article
LanguageRussian
Published Russia (Federation) 01.11.1977
Subjects
Animals
Anura
Cell Membrane Permeability - drug effects
Membrane Potentials - drug effects
Ranidae
Ranvier's Nodes - physiology
Sodium - metabolism
Tetrodotoxin - pharmacology
Trimecaine - pharmacology
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Summary:Asymmetrical displacement currents (Id) in the frog Ranvier node (R. ridibunda) treated with tetrodotoxin and tetraethylammonium were studied by the use of ramp-voltage pulses. In some experiments both ramp- and step-voltage pulses were used. The net Id consists of two components, one of which Id (I) can be blocked by local anesthetic trimecaine, or inactivated with the 10 ms depolarizing prepulse sufficiently large to inactivate the sodium current in the same node (before Na+ removal and TTX application). Parameters of the steady state charge distribution are very close (though not identical) to that of the peak sodium permeability vs. potential relation. The charge carrying Id (I) is estimated as 0.3--0.5 of the net displaced charge. The results suggest that trimecaine- and inactivation-sensitive component of Id may be the true gating current of Na+ channels.
ISSN:0365-9615