Effects of PFC D4R activation on total and phosphorylated PFC CaMKII-α expression levels and effects of intra-PFC CaMKII-α phosphorylation inhibition on PFC D4R modulation of fear and morphine reward behaviors. A, Sample Western blots showing PFC pCaMKII-α bands relative to loading controls in intra-PFC VEH, SKF 81297 (100 ng), or PD 168077 (50 ng) -treated rats. B, Sample Western blots showing representative PFC tCaMKII-α bands relative to loading controls in intra-PFC VEH, SKF 81297 (100 ng), or PD 168077 (50 ng) -treated rats. C, Coadministration of PD 168077 (50 ng) with the CaMKII-α phosphorylation inhibitor AIP (1 μg; n = 8) reverses the effects of intra-PFC D4R activation on potentiation of subthreshold fear memory acquisition, with AIP having no effect on its own (n = 8), relative to PD 168077 (50 ng) on its own (n = 8). D, Similarly, reversing the potentiation of D4R-mediated fear memory recall with AIP blocks the potentiation of sub-reward threshold morphine reward CPP in these same groups. Rats receiving AIP alone show no potentiation of morphine reward CPP. **p < 0.01.