Intracerebroventricular (ICV) injection of ouabain, a specific Na-K ATPase inhibitor, induced behavioral changes in rats, a putative animal model for mania. The binding of ouabain to Na-K ATPase is known to affect signaling molecules in vitro such as extracellular signal-regulated kinase1/2 (ERK1/2) and Akt, which promotes protein translation. In this study, we investigated changes in the phosphorylation of proteins related to translation initiation, including ERK1/2, p90 ribosomal s6 kinase (p90RSK), Akt, p70 ribosomal S6 kinase (p70S6K), and small ribosomal protein 6 (S6) in rat frontal cortex after ICV injection of ouabain (1 mM). Ouabain treatment induced hyperlocomotion of rats, which was maintained until 24 hr after single injection. Along with the prolonged hyperactivity of rats, phosphorylation level of ERK1/2, p90RSK, and Akt increased at 0.5, 1, 2, 4, 8, and 24 hr in rat frontal cortex after ICV injection of ouabain. Phosphorylation of p70S6K also up-regulated until 24 hr after ouabain treatment. Moreover, ouabain treatment increased the phosphorylation of S6 at Ser240/244, regulated by Akt-mTOR-p70S6K pathway, and at Ser235/236, regulated by ERK1/2-p90RSK pathway. Taken together, single ICV injection of ouabain induced activation of protein translation initiation pathway regulated by ERK1/2 and Akt, along with prolonged hyperactivity. These findings may suggest the important role of protein translation pathway in the brain mediating the behavioral changes of the ouabain animal model for mania.