Use of protein kinase C inhibitors results in rapid [Mg 2+] i mobilization in primary cultured rat aortic smooth muscle cells: are certain protein kinase C isoforms natural homeostatic regulators of cytosolic free Mg 2+?

Abstract

The effects of five different protein kinase C inhibitors—calphostin C, chelerythrine, bisindolylmaleimide I, staurosporine and Gö6979—on intracellular free magnesium ([Mg 2+] i) content and mobilization were investigated in primary, cultured rat aortic smooth muscle cells. All these protein kinase C inhibitors significantly and rapidly increased [Mg 2+] i both in normal media (1.2 mM Mg 2+) and in Mg 2+ free media. These data suggest that the increments of [Mg 2+] i, induced by the diverse protein kinase C inhibitors, are derived from the release of bound intracellular Mg 2+ and that activation of protein kinase C isozymes are normally responsible for helping to maintain basal levels of [Mg 2+] i in rat aortic smooth muscle cells.