Recently, we have proposed that inhibition of protein kinase Cδ (PKCδ) may be a useful target for protection against methamphetamine (MA)-induced dopaminergic toxicity. We have demonstrated that treatment with MA resulted in a significant decrease in phosphorylation of tyrosine hydroxylase (TH) at Ser40 in the striatum, but not in the phosphorylation of TH at Ser31. Treatment with rottlerin, a PKCδ inhibitor or PKCδ antisense oligonucleotide (ASO) significantly attenuated MA-induced reductions in the phosphorylation of TH at Ser40 and in the expression of protein kinase A (PKA). This attenuation was significantly counteracted by H89, a PKA inhibitor. Treatment with rottlerin or ASO significantly attenuated the MA-induced increase in protein phosphatase (PP) 2A activity. FTY720, a PP2A activator, significantly reversed the PKCδ inhibition-mediated recovery in phosphorylation of TH against MA insult. Consistently, H89 and FTY720 counteracted PKCδ inhibition-mediated recovery against MA-induced behavioral impairments, respectively. The effects, mediated by rottlerin or ASO, in MA-treated wild-type-mice were comparable to those in MA-treated PKCδ(-/-) -mice. However, neither inhibition of mitogen-activated protein kinase (MAPK) subfamily nor inhibition of calcium calmodulin kinase II significantly altered PKCδ inhibition-mediated attenuation against MA-induced impaired phosphorylation of TH. Our results suggest that genetic or pharmacological inhibition of PKCδ requires modulation of PKA expression and/or PP2A activity for attenuating impairments in the phosphorylation of TH at Ser40 and behavioral activity induced by MA. This article is protected by copyright. All rights reserved.