A Microfluorometric Method for Simultaneous Measurement of Changes in Cytosolic Free Calcium Concentration and pH in Single Cardiac Myocytes.

Abstract
We describe a new system to measure changes in cytosolic free Ca concentration ([Ca2+]i) and pH (pHi) simultaneously using the dyes fura-2 and BCECF, and a random access camera with computer-operated synchronously-changing excitation and emission filters. Fluorescence intensities for fura-2 and BCECF were recorded from rat cardiac myocytes and calibrated in vivo using multiple-point determinations. [Ca2+]i and pHi were 88.6 +/- 32.8 nM and 7.16 +/- 0.12, respectively.