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The conductance of single cardiac sodium channels from guinea pig depends on the intracellular sodium concentration.
- Source :
-
Biochimica et biophysica acta [Biochim Biophys Acta] 1991 Sep 30; Vol. 1068 (2), pp. 254-6. - Publication Year :
- 1991
-
Abstract
- Currents through DPI 201-106 modified single sodium channels have been measured in cell-free inside-out patches from guinea-pig ventricular myocytes. Single-channel conductance and reversal potential of the sodium channel have been calculated at different intracellular sodium concentrations [( Na+]i) from microscopic I-V curves, which were obtained by application of linear voltage ramps. The relation between the reversal potential and [Na+]i could be fitted with a modified Goldman-Hodgkin-Katz equation with a relative permeability for K+ over Na+ ions of 0.054. The zero-current conductance of the Na channel as a function of [Na+]i shows a plateau value at low Na concentrations, and increases in a sigmoidal manner at higher concentrations. It is concluded that the Na channel can carry outward currents and that its conductance depends on [Na+]i.
Details
- Language :
- English
- ISSN :
- 0006-3002
- Volume :
- 1068
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Biochimica et biophysica acta
- Publication Type :
- Academic Journal
- Accession number :
- 1655033
- Full Text :
- https://doi.org/10.1016/0005-2736(91)90217-v