We can propose that neurons are damaged and probably they are in death process. Thus, astrocytes could have become activated in response to neuronal damage early after (PhTe)2 injection. In this context, the neuronal damage showed by immunocytochemistry and flow cytometry in the striatum could support the accentuated vacuolization of cellular bodies of rat brain after in vivo exposure to (PhTe)2, reported by Maciel et al. (2000).

Consistent with the pro-apoptotic effect of (PhTe)2 on striatal neurons, we found a prominent increase of GFAP and vimentin GSK3235025 ic50 expression apparent at 6 days post injection, which suggest that, at least at this time, cells were reactive astrocytes. Astrogliosis is the normal physiological response essential for damage containment. However, it can also have detrimental effects on neuronal survival and axon regeneration, particularly in neurodegenerative insults. It is believed that progressive changes in astrocytes as they become reactive are finely regulated by complex intercellular and intracellular signaling mechanisms. Reports describing whether the MAPK pathways are upregulated in astrocytes in vivo are mixed. Nonetheless, increased phosphorylation level of Erk and/or p38MAPK takes part in the response of astrocytes to insults ( Ito et al., 2009). Although the evident complexity involving

the participation of these signaling mechanisms Ku-0059436 cost in reactive astrogliosis, different Resveratrol components of MAPK signaling are activated under distinct pathological conditions and in different cell types, which may indicate a common mechanism. Thus, the activation of MAPKs detected in the striatum of acutely treated rats could be associated with the program of astrogliosis detected in our experimental condition. In the present study we demonstrate that the neurotoxicant (PhTe)2 administered s.c. is able to elicit a cell response through misregulation of signaling mechanisms attaining neural cells in the striatum of young rats. At present we do not know if the effect of the neurotoxicant is directly on

the neural cell or if it is a consequence of the activation of other stress responses, like neuroinflammation. Further studies will be necessary to clarify this point. Taking into account the present results, the proposed mechanism for the action of (PhTe)2 in the striatum of young rats is summarized in Fig. 9. We think these results shed light into the mechanisms of (PhTe)2-induced neurodegeneration in rat striatum, evidencing a critical role for the PKA, MAPK and Akt signaling pathways causing disruption of cytoskeletal homeostasis, which could be related with apoptotic neuronal death and astrogliosis. The authors declare that there are no conflicts of interest. This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS), PRONEX and Propesq-UFRGS.