IMR Press / FBL / Volume 2 / Issue 1 / DOI: 10.2741/A157

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article

Elevation of extracellular magnesium rapidly raises intracellular free Mg2+ in human aortic endothelial cells: is extracellular Mg2+ a regulatory cation?

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1 Department of Physiology, State University of New York, Health Science Center at Brooklyn, NY 11203, USA
2 Departments of Medicine, State University of New York, Health Science Center at Brooklyn, NY 11203, USA
3 The Center for Cardiovascular and Muscle Research, State University of New York, Health Science Center at Brooklyn, NY 11203, USA
Front. Biosci. (Landmark Ed) 1997, 2(1), 13–17; https://doi.org/10.2741/A157
Published: 1 June 1997
Abstract

Extracellular magnesium ions [Mg2+]o are known to regulate functions of endothelial cells, but whether [Mg2+]o can alter intracellular free ionized magnesium [Mg2+]i in these cells remains unknown. The present studies, using digital imaging microscopy and the Mg2+ fluorescent probe, mag-fura-2, determined effects of elevation of [Mg2+]o on [Mg2+]i in cultured human aortic endothelial cells. With normal Mg2+(1.2 mM)-containing incubation media, [Mg2+]i was 0.51+/-0.04 mM with a heterogeneous distribution. The ratio of [Mg2+]i/[Mg2+]o was 0.52+/-0.07. Elevation of [Mg2+]o up to 4.8 mM increased [Mg2+]i to 0.80+/-0.07 mM in 2-10 min and lowered the ratio of [Mg2+]i/[Mg2+]o to 0.16+/-0.02. Irrespective of the observed increments of [Mg2+]i, a subcellular heterogeneous distribution of [Mg2+]i was always evident in all cells tested. Our results suggest that [Mg2+]o can regulate [Mg2+]i more rapidly than heretofore believed, supporting the hypothesis that extracellular Mg2+ can exert regulatory effects on endothelial cell functions and probably act as extracellular regulatory cations.

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