Practical considerations for using mag-fura-2 to measure cytosolic free magnesium.

The development of fluorescent ion-selective indicators for magnesium has provided valuable tools for measuring second-by-second changes in cytosolic magnesium activity. In the course of establishing appropriate protocols for using one of these indicators, mag-fura-2, to measure magnesium activity in BC3H-1 cells and chick ventricular myocytes, many potential pitfalls and limitations of this technique have been encountered and addressed. These observations are presented for the purpose of providing guidelines regarding the appropriate use of this indicator and on factors influencing the interpretation of resulting data.