摘要
目的研究神经生长因子(NGF)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Northernblot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 ,NGF通过抑制cNOS活性 。
Aim To study the effects of nerve growth factor (NGF) on nitric oxide (NO) release and constitutive nitric oxide synthase (cNOS) gene expression induced by glutamate (Glu) in cortical neuronal cultures. Methods Neuron viability was measured to assay NGF effect. NO content and the expression of cNOS mRNA were determined by fluorometric method and Northern blotting respectively. Results Glu (0.5～2.0 mmol/L) induced a marked increase of neuronal death and NO content in cultured cerebral cortical neurons. L_NAME (100 μmol/L) and NGF (100 μg/L) significantly increased neuronal surviving and decreased NO release. Hemolglobin (Hb), which binds NO, completely prevented Glu_induced cell death and NO release at 500 μmol/L. NGF (50,100 μg/L) significantly inhibited cNOS mRNA expression induced by Glu (0.5 mmol/L). Conclusion NO mediates Glu neurotoxicity in cortical neuronal cultures and NGF protects the neurons against Glu neurotoxicity via inhibiting the activity of cNOS and the release of NO.
