U0126 was screened out as an anti-inflammatory agent that inhibited AP-1 transcription with IC50 value of 1μM and had no interactions with GREs. U0126 binds MEK1/2 in a unique site. This inhibition of MEK1/2 is noncompetitive with ERK and ATP. U0126 showed no effects on other MAPKKs. In HT22 cells, U0126 treatment significantly inhibited the cell injury caused by oxidative glutamate toxicity and remarkably blocked the phosphorylation of ERK1/2. Besides that, U0126 exerted no neuroprotection against other stimuli such as TNFα and actinomycin D. U0126 treatment also protected the primary cultured cortical neurons from oxidative glutamate toxicity and hypoxia/reoxygenation.