Asai S, Zhao H, Takahashi Y, Nagata T, Kohno T, Ishikawa K
Department of Pharmacology, Nihon University School of Medicine, Tokyo, Japan.
Neuroreport. 1998 Dec 1;9(17):3863-8. doi: 10.1097/00001756-199812010-00018.
Using a dialysis electrode, we recently developed an oxygen-independent system for real-time measurement of the glutamate concentration in the extracellular space ([Glu]e) during ischemia. This system allows separate evaluation of intra-ischemic biphase [Glu]e elevation, i.e. release from synaptic vesicles (1st phase), reversed uptake of glutamate from metabolic pools in neuronal cells (2nd phase), and post-ischemic glutamate re-uptake in ischemia-reperfusion models. Using the system, we attempted to clarify the relationship between biphase glutamate release and brain temperature in a model of acute global ischemia produced by transecting both carotid arteries. Our results showed that, in contrast to mild hyperthermia, hypothermia did not inhibit the 1st phase of [Glu]e release, and changes in intra-ischemic brain temperature had a minimal effect on the 2nd phase of [Glu]e elevation during severe acute ischemia. These findings, together with our previous data, indicate that brain temperature change in the intra-ischemic period plays an important role in disturbance of the glutamate re-uptake system during ischemia.
我们最近使用透析电极开发了一种不依赖氧气的系统，用于在缺血期间实时测量细胞外空间中的谷氨酸浓度（[Glu]e）。该系统允许分别评估缺血期间双相[Glu]e升高，即从突触小泡释放（第一阶段）、神经元细胞代谢池中谷氨酸的反向摄取（第二阶段）以及缺血再灌注模型中缺血后谷氨酸的再摄取。使用该系统，我们试图在双侧颈动脉横断产生的急性全脑缺血模型中阐明双相谷氨酸释放与脑温之间的关系。我们的结果表明，与轻度热疗相反，低温并不抑制[Glu]e释放的第一阶段，并且在严重急性缺血期间，缺血期间脑温的变化对[Glu]e升高的第二阶段影响最小。这些发现与我们之前的数据一起表明，缺血期间脑温变化在缺血期间谷氨酸再摄取系统的紊乱中起重要作用。
