Background and purpose: Antioxidants are known to have protective and beneficial effects in the depression. Menthol is an antioxidant compounds in some plants. On the basis of our knowledge, no scientific study has investigated the antidepressant-like effects of menthol. Therefore, present study was thus conducted to evaluate the antidepressant-like effects of menthol by forced swimming test (FST) through dopaminergic system in a mice model.
Materials and Methods: The mice were intra-peritoneally (i.p.) administrated with menthol (10-30 mg/kg) 1 h before the FST. For evaluating the involvement of the dopaminergic system in the antidepressant activity of menthol, SCH 23390 (a dopamine D1 receptor antagonist), sulpiride (a dopamine D2 receptor antagonist) and haloperidol (non-selective dopamine receptor antagonist) were administered 15 min before menthol administration (10 mg/kg).
Results: Intra-peritoneally administration of menthol reduced immobility time and increased swimming and climbing times. It did not also cause significant changes in spontaneous locomotor function in the open-field test (OFT). In addition, pre-treatment of the mice with SCH23390, sulpiride, haloperidol blocked the anti-immobility effect of menthol in the FST.
Conclusion: Administration of menthol exerted antidepressant-like effects through dopaminergic (D1 and D2) system.