Modulation of L-type calcium channels by sodium ions.
- 15 May 1992
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 89 (10), 4417-4421
- https://doi.org/10.1073/pnas.89.10.4417
Abstract
It is universally believed that the removal of external sodium ions is without effect on calcium current. We now report that in enzymatically isolated guinea pig ventricular cells, the replacement of external sodium ions with certain other cations causes a 3- to 6-fold increase in peak L-type calcium current. The increase in current is reversibly blocked by L-type calcium-channel antagonists, not mediated by changes in internal calcium, and is inhibited by intracellular 5'-adenylyl imidodiphosphate, a nonhydrolyzable ATP analogue. The effects of sodium removal (and isoproterenol) were almost completely blocked by intracellular application of a specific (peptide) inhibitor of cAMP-dependent protein kinase. These experiments demonstrate a previously unknown effect of sodium ions to modulate calcium-channel phosphorylation via cAMP-dependent protein kinase.Keywords
This publication has 38 references indexed in Scilit:
- Changes of the subsarcolemmal Na+ concentration in internally perfused cardiac cellsBiochimica et Biophysica Acta (BBA) - Biomembranes, 1991
- Regulation of Cardiac L-Type Calcium Current by Phosphorylation and G ProteinsAnnual Review of Physiology, 1990
- Permeation in the dihydropyridine-sensitive calcium channel. Multi-ion occupancy but no anomalous mole-fraction effect between Ba2+ and Ca2+.The Journal of general physiology, 1990
- Augmentation of cardiac calcium current by flash photolysis of intracellular caged-Ca2+ moleculesNature, 1989
- β-Adrenergic modulation of calcium channels in frog ventricular heart cellsNature, 1984
- Ca2+ channel modulation by 8-bromocyclic AMP in cultured heart cellsNature, 1983
- Properties of single calcium channels in cardiac cell cultureNature, 1982
- Ca-dependent K channels with large unitary conductance in chromaffin cell membranesNature, 1981
- Sodium Requirement for the Positive Inotropic Action of Isoproterenol on Guinea Pig AtriaScience, 1978
- ATP AnalogsPublished by Wiley ,1975