Respiratory activity of striatal nonsynaptic and synaptic mitochondria isolated from 2-month-old FVB/NJ (blue traces) and YAC128 (red traces) mice. Representative traces of oxygen consumption by either striatal nonsynaptic (A) or striatal synaptic (B) mitochondria. Where indicated, mitochondria (30μg protein), 200μM ADP, or 60μM 2,4-dinitrophenol (2,4-DNP) were added. The incubation medium was supplemented with the Complex II substrate succinate (3mM) plus glutamate (3mM). Additionally, incubation medium was supplemented with 0.1% BSA (free from fatty acids) to maintain mitochondrial integrity (Lai and Clark, 1989). The pooled group results demonstrating respiratory rates are shown for striatal nonsynaptic (C) and striatal synaptic (D) mitochondria. Data are mean ± SEM, n = 5 (nonsynaptic), n = 4 (synaptic).