Bullock R, Butcher S P, Chen M H, Kendall L, McCulloch J
Department of Neurosurgery, University of Glasgow, Scotland.
J Neurosurg. 1991 May;74(5):794-802. doi: 10.3171/jns.1991.74.5.0794.
The excitatory neurotransmitters glutamate and aspartate are an important factor in the causation of ischemic brain damage. The concentration of glutamate and aspartate was serially measured in extracellular fluid using in vivo microdialysis after induction of a subdural hematoma or after a sham operation in the rat. Measurements were made in the cortex underlying the hematoma and in the ipsilateral hippocampus, and these findings were correlated with regional cerebral blood flow (CBF), measured autoradiographically 2 hours after hematoma induction. In the severely ischemic cortex underlying the hematoma (mean CBF less than 25 ml/100 gm/min), glutamate and aspartate content increased more than 750% over basal levels. In individual animals the magnitude of glutamate release correlated with the extent of the focal ischemic zone under the hematoma (r = 0.907). Hippocampal glutamate levels rose 339%, yet regional CBF was preserved (114 ml/100 gm/min). This accords with focal hypermetabolism in this model, and may imply a glutamate-mediated "excitotoxic" process after subdural hematoma.
兴奋性神经递质谷氨酸和天冬氨酸是导致缺血性脑损伤的一个重要因素。在大鼠诱导形成硬膜下血肿或进行假手术后，使用体内微透析技术连续测量细胞外液中谷氨酸和天冬氨酸的浓度。在血肿下方的皮质以及同侧海马体进行测量，并将这些结果与血肿诱导2小时后通过放射自显影法测量的局部脑血流量（CBF）相关联。在血肿下方严重缺血的皮质（平均CBF低于25 ml/100 gm/min）中，谷氨酸和天冬氨酸含量比基础水平增加了750%以上。在个体动物中，谷氨酸释放的幅度与血肿下方局灶性缺血区域的范围相关（r = 0.907）。海马体中的谷氨酸水平上升了339%，但局部CBF得以保留（114 ml/100 gm/min）。这与该模型中的局灶性代谢亢进相符，可能意味着硬膜下血肿后存在谷氨酸介导的“兴奋毒性”过程。
