Objective: To explore the feature of selective neuron injury after prolonged seizure in mature brain

and explore the relationship of serum neuron specific enolase (NSE) with brain damage. Methods: Prolonged seizures were evoked by Megimide in 30 adult Wistar rats . All of the rats experienced prolonged seizures with ～duration of 1520 min. Every five rats sacrificed at the time of 4

12

24

48

72 hours and 7days after seizure stopped. The dead neurons were observed microscopically ( HE & Thioine staining) and electron-microscopically ’at the areas of hippocampus

and the cortexes. At the same time points

the level of NSE in rats sera was tested by ELISA. Results: ⑴ There was an obvious selective neuron death after prolonged seizure. The process of neurons’ death was remarkably shown even at the early stage of 4 hours after severe seizures. The peak of necrosis ～process was counted in 2448 hours after the seizure (180±38 cells) and it was 5 times higher than the control (38±6 cells). (2) By ELISA study

NSE level also increased after 4 hours after the seizure

and reached its peak (concentration at 48h5.13±)’(0.77nmol/L---much higher than controls3.53±)0.87nmol/L. Conclusion: Prolonged seizure in mature brain will lead to selective neuron death mainly at the area of hippocampus

which was in accord with the process of the change of level of NSE in sera. Serum NSE level could be a useful marker for detecting neuron death.