HPLC analysis of the effects of NBQX and coQ10 treatments on brain dopamine concentration. Head homogenates of 10-day-old Ddc-Gal4>DJ-1A RNAi flies treated with NBQX or coQ10 were measured for dopamine content by HPLC. These were compared with untreated Ddc-Gal4>DJ-1A RNAi flies. Control Ddc-Gal4/+ flies with or without drug treatment were similarly analyzed. Results are represented as mean ± SD of 21 homogenized heads for each genotype and drug treatment. *: P < 0.05 in ANOVA with Dunnett's post test. Note that there appears to be a significant variation in dopamine level between untreated control and DJ-1 RNAi flies used in this experiment and those used in Fig. 4. This could be due to slight variations in animal age, which can have a strong effect on brain dopamine level , or due to sensitivity of dopamine stability to variations in each experimental condition.