Abstract
Ethnopharmacological relevance:
Tabebuia avellanedae Lorentz ex Griseb is a plant employed in tropical America folk medicine for the treatment of several diseases, including depressive disorders.
Aim of the study:
To investigate the ability of Tabebuia avellanedae ethanolic extract (EET) administered chronically to cause an antidepressant-like effect in the tail suspension test (TST), a predictive test of antidepressant activity, and to reverse behavioral (hyperactivity, anhedonic-like behavior and increased immobility time in the TST) and biochemical changes induced by olfactory bulbectomy (OB), a model of depression, in mice.
Materials and methods:
Mice were submitted to OB to induce depressive-related behaviors, which were evaluated in the open-field test (hyperactivity), splash test (loss of motivational and self-care behavior indicative of an anhedonic-like behavior) and TST (increased immobility time). Phosphorylation levels of Akt, GSK-3β, ERK1/2 and CREB, as well as BDNF immunocontent, were evaluated in the hippocampus of bulbectomized mice or sham-operated mice treated for 14 days by p.o. route with EET or vehicle.
Results:
EET (10 and 30mg/kg) given 14 days by p.o route to mice reduced the immobility time in the TST without altering locomotor activity, an indicative of an antidepressant-like effect. EET per se increased both CREB (Ser(133)) and GSK-3β (Ser(9)) phosphorylation (at doses of 10-30 and 30mg/kg, respectively) in sham-operated mice. OB caused hyperactivity, loss of motivational and self-care behavior, increased immobility time in the TST and an increase in CREB and ERK1 phosphorylation, as well as BDNF immunocontent. EET abolished all these OB-induced alterations except the increment of CREB phosphorylation. Akt (Ser(473)) and ERK2 phosphorylation levels were not altered in any group.
Conclusions:
EET ability to abolish the behavioral changes induced by OB was accompanied by modulation of ERK1 and BDNF signaling pathways, being a promising target of EET. Results indicate that this plant could constitute an attractive strategy for the management of depressive disorders, once more validating the traditional use of this plant.
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