超低温断血流对猴脑氨基酸类神经递质的影响

目的 研究猴脑选择性超深低温断血流复苏过程中脑组织细胞外液的谷氨酸(glutamate, Glu)和γ-氨基丁酸(gamma-aminobutyric acid, GABA)的动态变化.方法 恒河猴7只,随机分为两组:四血管(双侧颈总动脉及椎动脉)阻断冷灌注组(简称四血管组,n=4),两血管(双侧颈总动脉)阻断冷灌注组(简称两血管组,n=3).将微透析管置入右顶叶脑组织内,自缺血前30min开始收集细胞外液,用高效液相色谱-紫外法测定脑选择性超深低温断血流复苏前后脑组织细胞外液Glu及GABA的浓度.结果 四血管组Glu在常温断血流缺血后即迅速升高(P<0.05),低温冷灌注后较常温缺血时明显下降至低于缺血前水平(P<0.05);恢复血流后行再灌注复温,早期即开始升高,迅速达到并超过灌注前水平.GABA则变化不大.两血管组Glu在常温断血流预缺血后迅速升高(P<0.05),低温冷灌注后较常温缺血时明显下降(P<0.05),下降幅度较四血管组明显;恢复血流后行再灌注复温,和行低温冷灌注时相比,Glu变化不明显.GABA在常温断血流预缺血、低温冷灌注及恢复血流复温时均变化不大.结论 脑选择性超深低温断血流复苏通过抑制谷氨酸等兴奋性神经递质的释放而抑制其细胞毒性作用.

Effects of content of glutamate and Gamma-aminobutyric acid of macaca mulattas on resuscitation after selective cerebral ultra-profound hypothermia and blood flow occlusion

Objective To investigate the variations of glutamate and GABA in extracellular liquid of macaca mulatta of resuscitation after selective cerebral ultra-profound hypothermia and blood flow occlusion. Methods Seven macaca mulattas were randomly divided into two groups. four-vessel occlusion group (n=4) and two-vessel occlusion group( n=3). The tube of microdialysis was inserted into the lobe of parietal on the right side in order to collect the liquid of microdialysis, determinate the content of glutmate and GABA before and after cerebral selective ultra-profound hypothermia and blood flow occlusion with HPLC. Results In four-vessel occlusion group, the content of glutamate increase after blood flow occlusion (P<0.05). When Cold solution (4.0±0.5)℃ was perfused into the right ICA to cool down the brain, the content of glutamate decrease (P<0. 05). The content of glutamate quickly increased after recovering the blood flow and cerebral temperature (P<0.05). The content of GABA was stable. In two-vessel occlusion group, the content of glutmate increased after blood flow occlusion (P <0.05) . With cooling down the brain, the content of glutamate decreased. The content of glutamate was not increase after recovering the blood flow and cerebral temperature. The content of GABA was stable. Conclusion Selective ultra-profound hypothermia may provide protective effects through decreasing excitatory amino acid.