Na+/Mg2+ antiport in non-erythrocyte vertebrate cells

Abstract

Experiments, results and conclusions on Na+/Mg2, antiport in lymphocytes, HL60 cells, Ehrlich ascites tumor cells, platelets, pancreatic acinar cells, sublingual acini, hepatocytes, ruminal epithelial cells, kidney cells, smooth muscle cells, heart muscle cells and skeletal muscle cells were reviewed. Only in a few experiments was the Mg2+ efflux via the Na+/Mg2+ antiport studied directly by measuring the alterations in [Mg2+]o and intracellular Na+ content. In most cell types, the Na+/Mg2+ antiport was investigated indirectly by measuring [Mg2+], and [Na+]i after changing the physiological Mg2+ homeostasis by effectors or by loading the cells with Mg2+. The effects of inhibitors and incubation in Na+ -free medium on the alterations in [Mg2+]i and [Na+]i were taken as evidence of the Na+/Mg2+ antiport. By these methods, the Na+/Mg2+ antiport was found in all investigated mammalian cell types. As far as they have been studied, the kinetic properties and regulation of Na+/Mg2+ antiport are reviewed.