Figure 6.

VTA histological analysis and effects of intra-PFC D1R or D4R activation on fear memory processing and intra-VTA morphine reward CPP behaviors. A, Microphotograph showing typical intra-VTA injector location. B, Schematic summary of bilateral intra-VTA cannulae injector locations; ○ = intra-PFC VEH; ● = intra-PFC PD168077 (50 ng/0.5 μl); ■ = intra-PFC SKF81297 (100 ng/0.5 μl). C, Intra-PFC SKF81297 administration immediately before fear memory recall significantly attenuates freezing behaviors. D, Relative to VEH controls (n = 7), rats receiving intra-PFC SKF81297 (n = 8) do not display morphine CPP. E, Intra-PFC PD168077 (n = 7) administration during fear memory acquisition significantly potentiates subthreshold associative fear memory and F, potentiates intra-VTA morphine reward CPP relative to VEH controls (n = 8). **p < 0.01.