Figure 3.
ROS production in astrocytes is activated by [Ca2+]c. A, The calcium ionophore ionomycin increased ROS generation, measured here with DCF fluorescence. B, Simultaneous measurements of [Ca2+]c (fura-2) and ROS production (HEt) in cortical astrocytes during application of 100 μm ATP. The mean values of the rate of ROS production measured with HEt are shown in C. In this case, signals measured from the rate of increase of HEt fluorescence were normalized to the rate at baseline taken as 100%. DPI (0.5 μm) or apocynin (1 mm) were used as inhibitors of NADPH oxidase (gray columns). D, Cells were bathed in a Ca2+-free saline containing 500 μm EGTA. The addition of thapsigargin (0.5 μm) released Ca2+ from the endoplasmic reticulum and caused small transient increase in ROS production while completely suppressing the response to subsequent application of ATP.