目的 :探讨早期放射性脑损伤的机制。方法 :用在体微透析结合高效液相色谱法 ,对大鼠半脑照射后测定海马细胞外液谷氨酸含量。结果 :发现半脑照射后半个月照射侧谷氨酸含量上升 ,并与剂量相关 ,15Gy组和 3 0Gy组与未照射侧相比有显著差异。照射后 3个月恢复正常。结论 :认为谷氨酸神经递质的变化可能是放射性脑损伤综合作用的结果。 Objective: To explore the mechanism of early radiation brain injury. Methods: The content of glutamate in extracellular fluid of hippocampus was determined by in vivo microdialysis coupled with high performance liquid chromatography (HPLC). Results: The content of glutamate in the irradiated hemisphere was increased half a month after irradiation and was dose-dependent. There were significant differences between the 15Gy group and the 30Gy group in the unirradiated side. 3 months after irradiation returned to normal. CONCLUSIONS: It is thought that the changes of glutamate neurotransmitter may be the result of the combined effect of radioactive brain injury.