Ursolic acid affords antidepressant-like effects in mice through the activation of PKA, PKC, CAMK-II and MEK1/2

Abstract Background Ursolic acid has been shown to display antidepressant-like effects in mice through the modulation of monoaminergic systems. In this study, we sought to investigate the involvement of signaling pathways on the antidepressant-like effects of ursolic acid. Methods Mice were treated orally with ursolic acid (0.1 mg/kg) and, 45 min later they received the followings inhibitors by intracerebroventricular route: H-89 (PKA inhibitor, 1 μg/mouse), KN-62 (CAMK-II inhibitor, 1 μg/mouse), chelerythrine (PKC inhibitor, 1 μg/mouse), U0126 (MEK1/2 inhibitor, 5 μg/mouse), PD98059 (MEK1/2 inhibitor, 5 μg/mouse), wortmannin (PI3K irreversible inhibitor, 0.1 μg/mouse) or LY294002 (PI3K inhibitor, 10 nmol/mouse). Immobility time of mice was registered in the tail suspension test (TST). Results The anti-immobility effect of ursolic acid in the TST was abolished by the treatment of mice with H-89, KN-62, chelerythrine, U0126 or PD98059, but not with wortmannin or LY294002. Conclusions These results suggest that activation of PKA, PKC, CAMK-II, MEK1/2 may underlie the antidepressant-like effects of ursolic acid.