Real-time observations of intracellular Mg2+ signaling and waves in a single living ventricular myocyte cell

Abstract

Despite the important regulatory role of Mg2+ in metabolic pathways, its underlying mechanism is not completely understood at the single-cell level. This study examined the propagation and dynamics of Mg 2+ signaling across the cell membrane by employing the real-time visualization of intracellular Mg2+ waves in living ventricular myocytes using a combination of total internal reflection fluorescence microscopy and Nomarski differential interference contrast. Real-time Mg 2+ waves and sparks in a living cell membrane were observed using a fluorescent Mg2+ indicator (mag-fluo-4-AM) in the concentration range of 5 aM-5 μM. The intracellular locations of the fluorescent Mg2+ indicator were confirmed by adding Na+ATP. The Mg2+ sparks and waves showed random temporal propagation patterns in nonhomogeneous substructures. These results show that spatiotemporal intra-cellular Mg 2+ signaling information can be obtained for individual living cells.