Properties of intra- and intercellular Ca(2+)-wave propagation elicited by mechanical stimulation in cultured RPE cells

Membrane deformation induced by a mechanical stimulus increases the [Ca2+]i in cultured retinal pigment epithelial (RPE) cells, and in many other cell types. In this study, confocal microscopy and Ca(2+)-measurements using the fluorescent dye fluo-3 were used to measure the spatiotemporal characteristics of the Ca(2+)-wave propagation during a mechanical stimulation in Long Evans (LE) RPE cells or dystrophic Royal College of Surgeons (RCS) RPE cells. Ca2+ signals were recorded in the mechanically stimulated cell and in the neighboring cells. A regenerative Ca(2+)-wave with a decreasing rate of propagation was found in the stimulated cells. The rate of propagation was significantly slower in RCS-RPE cells compared to LE-RPE cells. Incubation with thapsigargin significantly lowered the propagation rate in both LE- and RCS-RPE cells. The amplitude of the [Ca2+]i-rise in the nucleus and cytoplasm was differentially modulated by protein kinase C in RCS-RPE cells, but not in LE-RPE cells. It is concluded that RCS-RPE cells have intracellular Ca(2+)-regulating properties which are different from those of LE-RPE cells.