Figure 4

Mitochondrial ROS scavenging ability following uncoupling or permeability transition. (A) Representative traces of ROS scavenging ability measurements. In trace 1, SOD, HRP and Amplex Red were added from start and 2 μM H₂O₂ was added at 7 min to obtain a reference value. In trace 2–5, HRP and Amplex Red were added 0.5, 1, 1.5 and 2 min after H₂O₂ administration, respectively, to measure the residual H₂O₂ concentrations and hence determine the mitochondrial ROS scavenging ability. (B) Same as panel A but with 1 mM Ca²⁺ present to induce permeability transition. (C) Mean residual H₂O₂ concentrations in the mitochondrial suspensions following addition of 2 μM H₂O₂. Experiments were performed with control, 225 pM valinomycin (Val), 200 nM CCCP and calcium-treated mitochondria. (D) Comparison of mitochondrial ROS production and ROS scavenging rates in heart mitochondria. Note the logarithmic scale. ROS scavenging rate following H₂O₂ addition was calculated over the first minute following addition of H₂O₂ and ROS production rate was calculated in the same set of experiments before addition of exogenous H₂O₂ for those samples where the Amplex Red system was present from start. Values are means ± S.E.M.* indicates p < 0.05 compared to control.