CONICET | Buscador de Institutos y Recursos Humanos

In a previous work (Neuroscience,129:529-38) we observed that animals exposed to the learned helplessness (LH) paradigm show a significant decrement in the light subunit of the interrnediate neurofilament (NFL) in the rat hippocampus. Enriched environment (EE) was proposed to reverse structural changes observed in animal models of depression. In this work we analyze the effect of EE in the depressive-like behavior and in the above mentioned NFL decrease in the hippocampus of LH rats. Besides, we tested if it also induces neurogenesis in animal s exposed to stressful conditions. Male rats in which LH behavior was induced. were kept for 21 days in a special cage with different devices: tunnels, ropes, a running wheel, etc. LH animals not kept in the EE (LH) were the control group. Depressive-like behavior (escape latency in an avoidance task) was measured in an avoidaru;e task, NFL was evaluated by immunohystochemistry, and the number of neurons that co-expressed BrdU (injected the first three days, 50mglkg)/ ~Tubulin III (an immature and mature neuronal marker) were quantified by double-immunofluorescence. LH-EE rats show a reversion of the depressive-like behavior, an increment in NFL In addition, according to the confocal quantification, LH animals have more neurogenesis than LH-EE. Finally, with regards to the percentage of Tuj-l + cells, no difference were observed in the studied groups. Therefore, the EE induces a revertion in the depressive-like behavior as w.ell as in the NFL reduction. However, no role for neurogenesis can be proposed in this matter. This work was supported by lunds provided by ANPCyT (PlCT05-11102), University 01 Buenos Aires (M013) and CONlCET (PIP 5870)