Use of protein kinase C inhibitors results in rapid [Mg2+](i) mobilizationin primary cultured rat aortic smooth muscle cells: are certain protein kinase C isoforms natural homeostatic regulators of cytosolic free Mg2+?

The effects of five different protein kinase C inhibitors-calphostin C, che lerythrine, bisindolylmaleimide I, staurosporine and Go6979-on intracellula r free magnesium ([Mg2+](i)) content and mobilization were investigated in primary, cultured rat aortic smooth muscle cells. All these protein kinase C inhibitors significantly and rapidly increased [Mg2+](i) both in normal m edia (1.2 mM Mg2+) and in Mg2+ free media. These data suggest that the incr ements of [Mg2+](i), induced by the diverse protein kinase C inhibitors, ar e derived from the release of bound intracellular Mg2+ and that activation of protein kinase C isozymes are normally responsible for helping to mainta in basal levels of [Mg2+](i) in rat aortic smooth muscle cells. (C) 2001 El sevier Science B.V. All rights reserved.