Fig. 7.

Mitochondrial activity of cytochrome c oxidase (complex IV). Complex IV was evaluated measuring oxygen consumption of purified mitochondria isolated from rat brain. Mitochondrial (0.3 mg/ml) were incubated in phosphate buffer, pH 7.4, at room temperature. Complex I was inhibited with rotenone. Complex III was inhibited with antimycin A, and stigmatellin. Subsequently, TMPD was added and the reaction was started by the addition of reduced ascorbate. Concentrations of 10, 25, 50, 60, and 70 µM of NO^• donor (SNAP) were used in (a) 1-month old and (b) 7-months old rats, and concentrations of 5, 10, 20, 30, and 40 µM cyanide (CN⁻) were used in (c) 1-month old and (d) 7-months old rats. Results are the means ± SEM of 3–6 separate experiments in duplicates. ^*p < 0.05, ^**p < 0.01 vs. control values and ^▲p < 0.01 vs. strains of same age.