Figure 4.

Intra-VTA microinjections of the PDE4 inhibitor rolipram during the conditioning phase attenuated the acquisition of CPP to cocaine. (a) Timeline of drug treatment and behavioral paradigm. Groups of rats received saline and cocaine place conditioning once daily for 8 days. Vehicle (1 μl) or rolipram (0.5 μg, 1 μl) was bilaterally infused into the VTA 20 min before each saline- or cocaine-pairing. (b) Pre-test indicates that rats did not exhibit significant baseline bias in place preference in all groups (n=7–9; p>0.05). (c) Intra-VTA infusions of rolipram significantly attenuated CPP in cocaine-conditioned rats but did not affect CPP scores in saline-conditioned rats (n=7–9; ^**p<0.01, ^***p<0.001). Error bars indicate SEM.