Evidences for the Involvement of Monoaminergic and GABAergic Systems in Antidepressant-like Activity of Tinospora cordifolia in Mice

The present study was taken up to investigate the effect of petroleum ether extract of Tinospora cordifolia (Wild.) Miers, on depression in mice. The extract (50, 100 and 200 mg/kg, p.o.) was administered for 14 successive days to Swiss young albino mice (either sex) and evaluated for antidepressant-like activity using tail suspension test and forced swim test. Petroleum ether extract at all three doses produced significant antidepressant-like effect in tail suspension test as well as in forced swim test and their efficacies were found to be comparable to imipramine (15 mg/kg, p.o.) and sertraline (20 mg/kg, p.o.). The extract at a dose of 50 mg/kg showed most potent effect and did not show any significant change in locomotor functions of mice as compared to control. The antidepressant-like effect of the extract was significantly reversed by pretreatment of animals with prazosin (a α(1)-adrenoceptor antagonist), sulpiride (a selective dopamine D(2)-receptor antagonist), p-CPA (a serotonin synthesis inhibitor) and baclofen (GABA-B agonist), when tested in tail suspension test. Moreover, petroleum ether extract also reduced the mouse whole brain monoamine oxidase (MAO-A and MAO-B) activities as compared to control, resulting in increase in the levels of brain monoamines. Therefore, the extract may have potential therapeutic value for the management of depressive disorders.