Figure 3.

Rates of neuronal ROS production in response to inhibition of mitochondrial respiration. The specific roles of mitochondria in ROS generation were studied further using the mitochondrially localized ROS fluorescent indicator MitoSOX. Traces A–C show the mean values measured from all neurons in a field of view in one representative experiment. MitSOX fluorescence was measured simultaneously with Rh123 during OGD/reoxygenation, and confirms that mitochondrial ROS generation is seen only before mitochondrial potential is lost. An additional increase in signal was seen on reperfusion. Inhibition of respiration with 1 mm NaCN in the presence of 0.2 mg/ml oligomycin (B) also induced multiphasic changes in ROS production (illustrated again below as the differentiated HEt trace). C, Another inhibitor of complex IV (1 mm NaN₃) in the presence of 0.2 mg/ml oligomycin caused a very similar sequence of changes in ROS generation. These data are summarized in D, in which the rates of ROS production during mitochondrial inhibition are illustrated, and the underlying mechanisms were again tested using FCCP (0.5 μm), oxypurinol (20 μm), and DPI (0.5 μm). Error bars indicate SEM.