Antidepressant-like effects of Trichilia catigua (Catuaba) extract:: evidence for dopaminergic-mediated mechanisms

Rationale: Currently available therapy for depression treatment is often associated with several undesirable side effects, and it is effective only in a certain portion of the population. Therefore, the identification of alternative therapeutic tools for the treatment of depression is still needed. Objective: The present study analyzed the possible antidepressant-like effects of the Brazilian medicinal plant, Trichilia catigua, in rodents. Attempts were also made to investigate some of the possible mechanisms implicated in its actions. Methods: The antidepressant-like effects of T catigua extract were assessed in two species of rodents (mice and rats) by means of in vivo (forced swimming test) and in vitro (monoamine reuptake and release in synaptosomal preparations) approaches. Results: Acute oral treatment with the extract of T. catigua produced antidepressant-like effects in the forced swimming model in both mice and rats. Anti-immobility actions of T. catigua extract in mice were significantly reversed by haloperidol or by chlorpromazine, but not by pimozide, ketanserin, spiroxatrine or p-chlorophenylalanine. In vitro, T. catigua extract concentration-dependently inhibited the uptake and increased the release of serotonin, and especially of dopamine, from rat brain synaptosomal preparations. Conclusions: The present study provides convincing evidence for a dopamine-mediated antidepressant-like effect of the active principle(s) present in the hydroalcoholic extract of T. catigua in mice and rats when in vivo and in vitro strategies were employed. Therefore, a standardized T. catigua extract or its purified constituents could be of potential interest for the treatment of depressive disorders.