Fig. 8. Illumination of rhod-2 loaded astrocytes caused mitochondrial Ca²⁺-loading. (A) Confocal images of an astrocyte loaded with the Ca²⁺-indicator rhod-2. During illumination, the rhod-2 signal over the whole cell rose, including that over mitochondria. Excitation of the dye was elicited using the 543 nm line of a HeNe laser set to 4% of total output. The images were taken using a x63 oil immersion lens; bar, 5 µm. The time course of rhod-2 signal change over a single mitochondrion is shown in B, which illustrates the signal measured over the mitochondrion marked by an arrow in A. Addition of antioxidants significantly reduced the rate of rise of rhod-2 signal (C), suggesting a role for ROS in the mitochondrial Ca²⁺-loading.