Magnesium homeostasis and cardiac cell function

Nearly 40 years ago, Carl Wiggers introduced the monograph entitled “Excitability of the Heart” [1] with the comment that “progress in basic research and in its practical application rests chiefly on the development of new tools for digging out nature’s secrets.” At the time, abnormalities in cardiac function resulting directly from changes in blood levels of magnesium (Mg2+) were not recognized. Similarly, altering intracellular magnesium (Mg2+ i) was thought to have a negligible effect on the excitability of the heart based on observations that neither high nor low extracellular magnesium concentration ([Mg2+]o) caused a noticeable change of the cardiac resting potential or action potential, although Brooks et al. [1] demonstrated the effects of calcium-magnesium interaction on the cardiac action potential.