[Protective effect of neurotrophin against glutamate neurotoxicity in cortical cultures]

This study was performed to investigate the effects of neurotrophins on glutamate cytotoxicity by using cultured cortical neurons. Primary cultures obtained from the cerebral cortex of fetal rats (17-19 days gestation) were used for experiments. NGF did not elicit tyrosine phosphorylation of Trks whereas BDNF induced Trk tyrosine phosphorylation within 10 min, followed by time-dependent decrease. Brief glutamate exposure to the cell induced delayed cytotoxicity. Similar cytotoxicity was observed with the brief application of a calcium ionophore, ionomycin, and nitric oxide (NO) generating agents, S-nitrosocysteine (SNOC) and SIN-1. Exposure of the cultures to NGF and BDNF for 1 or 24 hr prior to glutamate exposure reduced glutamate-induced cytotoxicity. In contrast, simultaneous addition of NGF and BDNF with glutamate did not affect glutamate-induced cytotoxicity. Ionomycin-induced cytotoxicity was prevented by exposing cultures to NGF and BDNF for 24-hr. Moreover, NGF and BDNF ameliorated cytotoxicity induced by SNOC and SIN-1. These results suggest that neurotrophins prevent NO mediated glutamate cytotoxicity.