Evidence of the involvement of the monoaminergic systems in the antidepressant-like effect of Aloysia gratissima

Aloysia gratissima (Verbenaceae) is an aromatic plant distributed in South America and, employed in folk medicine for the treatment of nervous systems illness, including depression. The neuroprotective and antidepressant-like activities of the aqueous extract of Aloysia gratissima (AE) administered orally has already been demonstrated.In this study the involvement of monoaminergic systems in the antidepressant-like effect of the AE was investigated. The implication of the monoaminergic systems in the antidepressant-like activity of Aloysia gratissima was evaluated using different pharmacological antagonists that were administered previously to the acute oral administration of AE (10mg/kg). The antidepressant-like effect was assessed in the TST and locomotor activity was evaluated in the open-field test in mice. The anti‐immobility effect elicited by AE in the TST was prevented by the pre-treatment of mice with the antagonists, NAN‐190 (5‐HT1A receptor), ketanserin (5‐HT2A/2C receptor), prazosin (α1‐adrenoceptor), yohimbine (α2‐adrenoceptor), SCH23390 (dopamine D1 receptor), or sulpiride (dopamine D2 receptor). These results indicate that the antidepressant‐like effect of AE in the TST is dependent on its interaction with the serotonergic (5‐HT1A and 5‐HT2A/2C), noradrenergic (α1 and α2−adrenoceptors) and dopaminergic (D1 and D2 receptors) systems, suggesting that this specie might act as a new potential resource for developing antidepressants to treat depressive disorders. [Display omitted]