Figure 5: Effect of VTA Oprk1 overexpression on working memory performance of non-dependent TH::Cre rats.
Panel A: Oprk1 mRNA expression in VTA of TH::Cre rats was increased (main effect of Viral Condition, ***p< 0.001) when exposed to the active virus (AAV5-Ef1a-Oprk1-DIO-EYFP) compared to the control virus (AAV5-Ef1a-DIO-EYFP). Panel B: Four weeks after viral infusions the animals were tested in the DNMST. Compared with the animals receiving the control viral infusions, the animals receiving active viral infusion in the VTA showed no significant difference in working memory performance at any delay tested.