Histone acetylation H3K9ac, H3K27ac, and H4K12ac markers (Panel A–C), and histone mythylation H3K27me3 marker (Panel D) at the Drd2 promoter of the striatum in young (gray bars) and aged (black bars) mice were measured as the percentage of input with ChIP assay and RT-PCR. Results indicated a significant decrease in H3K9ac, H3K27ac and H4K12ac, and significant increase in H3K27me3 in VEH groups in aged mice as compared to young mice. VPA and MS-275 significantly increased H3K9ac, H3K27ac and H4K12ac at the Drd2 promoter of the striatum of aged mice. *p<0.05, **p<0.01, ***p<0.001. n=6–8/group.