The Method for Simultaneous Registration of Changes in Intracellular Ca<sup>2</sup>+ Concentration and Cell Volume
In this study, we developed a method to determine Ganges in intracellular calcium concentration in single cells in which changes in volume can be measured simultaneously using Ca<sup>2</sup>+-sensitive fluorescent probe Fura-2 and a three-dimensional image surface reconstruction technique, respectively. This method shows that Fura-2 loading has no significant effect on kinetics of human lung epithelial A549 cells swelling in a hypotonic solution, and on kinetics of volume restoration. In the investigated range of cell volume modulation, we did not observe any significant changes in intracellular calcium concentration. Our data point to the fact that Ca<sup>2</sup>+-mediated signaling systems are not involved in autoregulation of volume in A549 cells under hypotonic conditions.