Respiration was similar in brain mitochondrial preparations from 24-month-old <i>PARK2^−/−</i> and wild type mice examined with standard oxygraphy.

<p>(<b>A</b>) Representative experiment with a crude mitochondrial pellet from striatum. Blue curve = oxygen (O₂) concentration expressed as nmol/mL; red curve = rate of oxygen consumption expressed as nmoles O₂/mL and min; ADP = addition of 400 µM ADP; OM = addition of 1 µg/mL oligomycin, a complex V inhibitor; KCN = addition of 1 mM KCN (non-respiratory oxygen consumption); (<b>B, C, D</b>) Bars showing state 3 respiration (respiration in the presence of substrates +ADP – non-respiratory oxygen consumption) and state 4 respiration (respiration in the presence of oligomycin – non-respiratory oxygen consumption) on complex I substrates (glutamate+malate); black bars = <i>PARK2^−/−</i>, white bars = wild type; data are expressed as nmoles O₂/mL and mg proteins and are shown as means ± SD; two animals, one per genotype, were analyzed the same day; the numbers between brackets indicate the number of individual animals of each genotype; (B) results from crude mitochondrial pellets from striatum (n = 6), (C) crude mitochondrial pellets from cortex (n = 7) and (D) purified mitochondria from whole brain (n = 2).