Protective effect of neurotrophin against glutamate neurotoxicity in coritcal 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 nduced by SNOC and SIN-1. These results suggest that neurotrophins prevent NO mediated glutamate cytotoxicity.