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目的 :研究脑反复缺血后海马细胞外液氨基酸和单胺递质及其代谢产物的变化规律。方法 :采用Pulsinelli和Brierley四血管关闭的方法 ,使大鼠脑反复缺血。用海马微管透析及高效液相电化学检测细胞外谷氨酸 (Glu) ,天冬氨酸 (Asp) ,牛磺酸 ,丙氨酸 ,丝氨酸 ,多巴胺 (DA) ,5 羟色胺 (5 HT)及其代谢产物浓度的变化。结果 :缺血期 ,Glu和Asp骤然增高 5 0倍和 3 0倍。缺血期间DA和 5 HT含量分别增加 3 0倍和 5 0倍 ,随后逐渐下降 ,再灌流 10 0min恢复到基础值水平。与此同时 ,它们的酸性代谢产物 3 ,4二羟苯乙酸 (DOPAC) ,高香草酸 (HVA) ,5 羟吲哚乙酸 (5 HIAA)在缺血期明显下降。结论 :缺血期间海马细胞外液兴奋性氨基酸和单胺递质急剧大量释放并触发膜离子通道改变 ,Ca2 + 超载 ,自由基反应 ,共同介导神经元缺血死亡
Objective: To study the changes of extracellular amino acids and monoamine neurotransmitters and their metabolites in hippocampus after repeated cerebral ischemia. Methods: The rats were subjected to repeated cerebral ischemia with Pulsinelli and Brierley four-vessel closure. The levels of extracellular glutamate (Glu), aspartate (Asp), taurine, alanine, serine, dopamine and serotonin (5 HT) were measured by microtubule- And its metabolite concentration changes. Results: In the ischemic period, Glu and Asp increased suddenly 50 times and 30 times. The levels of DA and 5 HT increased 30 and 50 times respectively during ischemia, and then decreased gradually. After reperfusion, the levels of DA and 5HT returned to their basal values at 10 min after reperfusion. In the meantime, their acidic metabolites 3, 4, DOPAC, HVA and 5 HIAA decreased significantly during ischemia. CONCLUSION: Excitatory amino acids and monoamine neurotransmitters in the extracellular fluid of hippocampus are released in large quantities during ischemia and trigger changes in membrane ion channels, Ca2 + overload and free radical reaction, which together mediate neuronal ischemic death