神经生长因子在培养的大鼠脑皮质神经细胞抑制谷氨酸引起的一氧化氮合酶基因表达及一氧化氮释放

目的 研究神经生长因子(NG F)对谷氨酸引起的原代培养的神经细胞一氧化氮(NO)释放和原生型一氧化氮合酶(cNOS)基因表达的影响。方法 测定神经细胞的生存力来分析NGF的作用。用荧光分析法测定细胞上清液NO 含量,用No rthern blot 杂交法观察cNOSmRNA表达。结果 谷氨酸(0 .5~ 2 .0mmol/L)引起神经元大量死亡,NO 过量释放。NOS 抑制剂L-NAME (100μmol/L)及NGF (100μg/L)显著抑制谷氨酸引起NO 释放及细胞死亡。NGF (50,100μg /L)显著降低谷氨酸引起的cNOSmRNA 的高表达。结论 NO 介导了谷氨酸对皮质神经元的毒性,NG F 通过抑制cNOS 活性,降低NO 释放来保护大脑皮质细胞对抗谷氨酸毒性。

Nerve growth factor prevents nitric oxide release and nitric oxide synthase gene expression induced by glutamate in primary cortical cultures of fetal rats

Aim To study the effects of nerve growth factor (NGF) on nitric oxide (NO ) release and constitutive nitricoxide synthase (cNOS) geneexpression induced by glutam ate(Glu) in cortical neuronal cuItures.Methods Neuron viability was measured to assay NGF effect.NO content and the expression of cNOS mRNA w ere determined by fluo-rometric method and Northe rn blotting respectively.Results Glu (0.5~2.0 mmolL)induced a marked increase of neuronal death and NO content in cultured cerebral cortical neurons.L-NAME (100μmol/L) and NGF (100μg/L) signifi cantly inereased neuronal surviving and decreased NO release.Hemolglobin (Hb),which binds NO,completely prevented Gluinduced cell death and NO release at 500 pμmoY L.NGF (50,100μg/L)sigmificantly inhibited cNOS m RNA expression induced by Glu (0.5 mmoYL).Conclusion NO mediates Gluneurotoxicity in cortical neuronal cultures and NGF protects the neurons against Gluneurotoxicity viainhibiting the activity of cNOS and the release of NO.