Abstract

Cotinine, the predominant metabolite of nicotine, appears to act as an antidepressant. We have previously shown that cotinine reduced immobile postures in Porsolt's forced swim (FS) and tail suspension tests while preserving the synaptic density in the hippocampus as well as prefrontal and entorhinal cortices of mice subjected to chronic restraint stress. In this study, we investigated the effect of daily oral cotinine (5 mg/kg) on depressive-like behavior induced by repeated, FS stress for 6 consecutive days in adult, male C57BL/6J mice. The results support our previous report that cotinine administration reduces depressive-like behavior in mice subjected or not to high salience stress. In addition, cotinine enhanced the expression of the vascular endothelial growth factor (VEGF) in the hippocampus of mice subjected to repetitive FS stress. Altogether, the results suggest that cotinine may be an effective antidepressant positively influencing mood through a mechanism involving the preservation of brain homeostasis and the expression of critical growth factors such as VEGF.