Long-term effects of juvenile exposure to VEH, MPH, FLX, or MPH+FLX on ERK-related gene expression within the VTA 2-months after the last injection (n= 8 per group). (A) ERK2, (B) CREB mRNA increased after MPH+FLX, but not after MPH or FLX when compared to the VEH-pretreated rats (p< 0.05, respectively). (C) BDNF mRNA did not vary after MPH (p> 0.05), but was decreased following FLX, and increased after MPH+FLX exposure (p< 0.05, respectively) when compared to the VEH-pretreated controls. (D) cFos mRNA was increased after MPH and MPH+FLX (p< 0.05, respectively), but did not vary after FLX treatment (p< 0.05) when compared to the VEH-pretreated controls. (E) Zif268 mRNA was increased following MPH and MPH+FLX (p< 0.05, respectively), but not FLX (p> 0.05) when compared to the VEH-pretreated controls. (F) mTOR mRNA was decreased by MPH and increased by MPH+FLX (p< 0.05, respectively), but did not vary after FLX exposure (p> 0.05) when compared to the VEH-pretreated controls. *Significantly different from VEH-pretreated controls (p< 0.05). Data are presented as fold change normalized to GAPDH (mean ± SEM).