Melatonin induces histone hyperacetylation in the rat brain

► Novel evidence that melatonin increases histone acetylation in rat brain. ► Significant increases in histone H3 and H4 acetylation in hippocampus and striatum. ► Significant increases in phospho-ERK 1/2 observed in hippocampus and striatum. ► Findings implicate chromatin remodeling and epigenetic regulation in melatonin action.