Title

Effects of intracellular free magnesium on calcium current in isolated cardiac myocytes

Document Type

Article

Publication Date

1988

Abstract

Magnesium ions play a fundamental role in cellular function, but the effects of changes in the concentration of intracellular ionized magnesium ([Mg2+](i)) on cell physiology have only recently received experimental attention. Increasing [Mg2+](i) from 0.3 to 3.0 mM in cardiac cells by internal perfusion has only small effects on the basal voltage-gated calcium current (I(Ca)) or on I(Ca) elevated by dihydropyridine calcium channel agonists. In contrast, I(Ca) elevated by cyclic adenosine monophosphate (cAMP)-dependent phosphorylation decreases by more than 50 percent. The effect of [Mg2+](i) is not due to changes in the concentration of cAMP or in the velocity of phosphorylation but rather appears to be a direct effect on the phosphorylated channel or on channel dephosphorylation.

Publication Title

Science

Volume

239

Issue

4841

First Page

778

Last Page

783

Comments

This article was published in Science, Volume 239, Issue 4841, Pages 778-783.

The published version is available at http://www.sciencemag.org/content/239/4841/778.abstract.

Copyright © 1988 AAAS.

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