Author(s): Almeida, R. D. ; Manadas, B. J. ; Melo, C. V. ; Gomes, J. R. ; Mendes, C. S. ; Grãos, M. M. ; Carvalho, R. F. ; Carvalho, A. P. ; Duarte, C. B.
Date: 2005
Persistent ID: https://hdl.handle.net/10316/12657
Origin: Estudo Geral - Universidade de Coimbra
Subject(s): BDNF; Apoptosis; Extracellular signal-regulated kinase (ERK); Phosphatidylinositol 3-kinase; Glutamate; Hippocampal neurons; Akt (PKB); Bcl-2
Neurotrophins protect neurons against glutamate excitotoxicity, but the signaling mechanisms have not been fully elucidated. We studied the role of the phosphatidylinositol 3-kinase (PI3-K) and Ras/mitogen-activated protein kinase (MAPK) pathways in the protection of cultured hippocampal neurons from glutamate induced apoptotic cell death, characterized by nuclear condensation and activation of caspase-3-like enzymes. Pre-incubation with the neurotrophin brain-derived neurotrophic factor (BDNF), for 24 h, reduced glutamate-evoked apoptotic morphology and caspase-3-like activity, and transiently increased the activity of the PI3-K and of the Ras/MAPK pathways. Inhibition of the PI3-K and of the Ras/MAPK signaling pathways abrogated the protective effect of BDNF against glutamate-induced neuronal death and similar effects were observed upon inhibition of protein synthesis. Moreover, incubation of hippocampal neurons with BDNF, for 24 h, increased Bcl-2 protein levels. The results indicate that the protective effect of BDNF in hippocampal neurons against glutamate toxicity is mediated by the PI3-K and the Ras/MAPK signaling pathways, and involves a long-term change in protein synthesis
