Effect of (2S,6S)-hydroxynorketamine on the levels of phospho-active forms of mammalian target of rapamycin (mTOR), protein kinase B (Akt), extracellular signal–regulated kinases (ERK1/2), p70S6 kinase (p70S6K), and eukaryotic initiation factor 4E binding protein (4E-BP1) in PC-12 cells. (A) Cells were treated with different concentrations of (2S,6S)-hydroxynorketamine (0–0.1 μM) for 1 h and processed for Western blot analysis. (B) Scatter plots illustrating the relative ratio of phosphorylated versus total forms of mTOR, Akt, ERK1/2, p70S6K, and 4E-BP1 in response to cell treatment with 0.5 nM of (R,S)-hydroxynorketamine are shown (n = 3 independent experiments). *, **P < 0.05, 0.01 (ANOVA) compared with control cells.