Fig. 4.

VP16-CREB action on calcium signalling pathways. ATP-elicited elevation of calcium was tested in astrocytes transducing VP16-CREB with no added calcium and presence of 0.5 mM EGTA (0Ca²⁺), or in the presence of inhibitors of calcium release from acidic lysosomal-related stores: 50 µM GPN or 100 µM Ned-19. Control refers to cells without any treatment other than viral vector infection. Representative traces in single cells (a–c) and quantification (d) of 100 µM ATP-induced calcium responses in Null and VP16-CREB-infected astrocytes. The data are the mean ± SEM of 6–8 independent experiments. *P < 0.05, **P < 0.01. e Representative images of astrocytes transfected with the ER calcium dye G-CEPIA1er before and after 100 µM ATP application. Representative traces (f) and quantification (g) of the decrease in ER calcium. Data are mean ± SEM of four independent experiments. ***P < 0.001