Comparative Analysis of Spontaneous and Stimulus-Evoked Calcium Transients in Proliferating and Differentiating Human Midbrain-Derived Stem Cells

Figure 3

Effects of thapsigargin on cytosolic calcium (a) and calcium addition to store-depleted differentiating stem cells (b). Cells were incubated in a calcium-free medium with 10 μM EGTA and then 2 μM thapsigargin was added (arrow). The cells were dye loaded in Krebs-Ringer solution (containing 2 mM calcium). The results from five independent experiments are shown, each represents the mean value from 29 to 65 cells, all of which with a calcium transient in response to thapsigargin (a). The cells were dye loaded in the presence of calcium and thapsigargin (2 μM). The dye was removed and the cells were primed with 2 μM thapsigargin for 12 min in calcium-free solution. Then 2 mM calcium was added, and the incubation lasted for 8–11 min. The results from four independent experiments are shown, each representing the mean value obtained from analysis of 23 to 39 cells, all of which displayed calcium transients in response to the addition of calcium (b).

(a)

(b)