Behavioral and biochemical evidences for antidepressant-like activity of palmatine in mice subjected to chronic unpredictable mild stress

Background: in the present study,antidepressant-like activity of palmatine was evaluated in unstressed and stressed young male swiss albino mice. methods: the animals were subjected to unpredictable mild stress daily for 21 successive days to induce depression-like behavior. palmatine (0.25,0.5,1 mg/kg,ip) was administered for 21 successive days to unstressed and stressed mice. the antidepressant-like activity was evaluated using the tail suspension test,forced swim test and sucrose preference test. results: palmatine (0.5 and 1 mg/kg,ip) significantly decreased immobility periods of unstressed and stressed mice in the forced swim test and tail suspension test,thus indicating its significant antidepressant-like activity. only the highest dose (1 mg/kg) of palmatine significantly reversed the stress-induced decrease in sucrose preference. there was no significant effect on locomotor activity of the mice by palmatine and fluoxetine. the antidepressant-like activity of palmatine was found to be comparable to fluoxetine (10 mg/kg) administered for successive 21 days. palmatine (0.5 and 1 mg/kg,ip) significantly reversed the stress-induced increase in brain catalase levels,mao-a activity,lipid peroxidation,plasma nitrite and corticosterone levels. conclusions: palmatine showed significant antidepressant-like activity in unstressed and stressed mice probably through inhibition of mao-a activity,decrease in plasma nitrite levels and due to its antioxidant activity. in addition,palmatine also showed antidepressant-like activity in stressed mice probably through decrease in plasma corticosterone levels. © 2014 institute of pharmacology,polish academy of sciences. published by elsevier urban & partner sp.