Time-dependent fluctuation of Akt/GSK-3 signalling pathway in HPC nuclear fraction and modulation by chronic agomelatine. Expression levels of Akt (A) and phosphorylation levels of Akt at Thr308(B) and at Ser473(C); expression levels of GSK-3 β (D); phosphorylation levels of GSK-3 β at Tyr216(E) and at Ser9(F) in nuclear fraction of HPC from rats chronically treated with vehicle (VEH, black bar) or agomelatine (AGO, white bar) and sacrificed 1 or 16 h after the last injection. Data expressed as above. Statistics as above. **p < 0.01 VEH 16 h after last injection vs. VEH 1 h after last injection; §p < 0.05, §§p < 0.01 AGO 16 h after last injection vs. AGO 1 h after last injection (n =8 rats/group).