A change in pH can alter the intracellular concentration of electrolytes such as intracellular Ca2+and Na2+ ([Na+]i) that are important for the cardiac function. For the determination of the role of pH in the cardiac magnesium homeostasis, the intracellular Mg2+ concentration ([Mg2+]i), membrane potential and contraction in the papillary muscle of guinea pigs using ion-selective electrodes chan...

Synthesis of the 31-amino acid, inner membrane protein MgtS (formerly denoted YneM) is induced by very low Mg2+ in a PhoPQ-dependent manner in Escherichia coli Here we report that MgtS acts to increase intracellular Mg2+ levels and maintain cell integrity upon Mg2+ depletion. Upon development of a functional tagged derivative of MgtS, we found that MgtS interacts with MgtA to increase the level...

Changes in [Mg2+] in a millimolar range have a significant inverse effect on the Ca2+- (or Sr2+)activated tension generation of skeletal muscle fibers. Single frog (Rana pipiens) semitendinosus muscle fibers were "skinned" (sarcolemma removed) and contracted isometrically in bathing solutions of varying [Ca2+] or [Sr2+] and [Mg2+] but a constant pH, [MgATP2-], [K+], [CP2-], [CPK], and ionic str...

This study investigated the role of the Na(+)-H+ exchanger (NHE) on angiotensin II (Ang II)-induced activation of Na(+)-dependent Mg2+ transport in vascular smooth muscle cells (VSMCs) from Wistar-Kyoto rats (WKY; n=20) and spontaneously hypertensive rats (SHR; n=20). Intracellular free concentrations of Mg2+ ([Mg2+]i) and Na+ ([Na+]i) and intracellular pH (pHi) were measured with the specific ...

Intracellular total Mg2+ and free Mg2+ are compartmentalized between cell organelles and within the cytosol. Different values of [Mg2+]i in the cytosol of the same cell type were measured by various investigators. A main reason for the differences is the uncertainty of the dissociation constants used for the Mg furaptra complex in the fluorescence method and for MgATP when 31P NMR was employed....

The Pb2+-catalyzed cleavage of tRNAPhe has been used to probe the effect of Na+ and Mg2+ binding to tRNA. Na+ is a noncompetitive inhibitor of the Pb2+-catalyzed cleavage. Millimolar Mg2+ is also a noncompetitive inhibitor. Analysis of the Mg2+ data show that at least two sites are involved in binding and that there is an interaction between the sites (cooperativity). Low-affinity Mg2+ binding ...