Abstract: To explore the effect of extract ginkgo biloba(EGB)on the dynamic expression of nitric oxide(NO)in the neuron apoptosis following hypoxia/reoxygenation(H/R), cerebral neurons of fetal Wistar rats were primarily isolated and cultured. Apoptosis of cultured cerebral cortical neurons following H/R was detected with Tunel and Flow cytometry method. The dynamic changes of NO metabolite nitrite(NO₂^-)in the supernatent solution of cultured neurons were measured by fluorospectrophotometry. No content in the apoptosis of cerebral neurons of fetal Wistar rats increased at H₂R₀ and H₁₈R₁₈ respectively to the normal control group. EGB showed an inhibition function to the increase of NO. AG inhibited the increase of NO at H₈R₁₈ , but showed no effect on the NO in H₂R₀ group. NO plays a role in the apoptosis of neurons following H/R, and EGB has a protective function on the apoptosis . The probable mechanism of EGB protection is its inhibition of NO.

Key words: nitric oxide, hypoxia reoxygenation, neuron, apoptosis, EGB