Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA.
J Neurosci Res. 2009 Sep;87(12):2812-20. doi: 10.1002/jnr.22092.
D-serine and L-glutamate play crucial roles in excitotoxicity through N-methyl-D-aspartate receptor coactivation, but little is known about the temporal profile of efflux during cerebral ischemia. We utilized a newly designed brain slice microperfusion device coupled offline to capillary electrophoresis laser-induced fluorescence to monitor dynamic efflux of endogenous D-ser and L-glu in response to oxygen glucose deprivation (OGD) in single acute hippocampus slices. Efflux profiles with 2-min temporal resolution in response to 24-min OGD show that efflux of D-ser slightly precedes efflux of L-glu by one 2-min sampling interval. Thus both coagonists are available to activate NMDA receptors by the time when glu is released. The magnitude of D-ser efflux relative to baseline values is, however, less than that for L-glu. Peak efflux during OGD, expressed as pre-OGD baseline values, was as follows: D-ser 254% +/- 24%, L-glu 1,675% +/- 259%, L-asp 519% +/- 128%, and L-thr 313% +/- 33%. L-glutamine efflux was shown to decrease significantly in response to OGD. The microperfusion/CE-LIF approach shows several promising attributes for studying endogenous chemical efflux from single, acute brain slices.
D-丝氨酸和 L-谷氨酸通过 N-甲基-D-天冬氨酸受体共激活在兴奋性毒性中发挥关键作用，但对于脑缺血期间的外排时间过程知之甚少。我们利用新设计的脑片微灌注装置与离线毛细管电泳激光诱导荧光相结合，监测单个急性海马切片对氧葡萄糖剥夺（OGD）的内源性 D-丝氨酸和 L-谷氨酸的动态外排。以 2 分钟的时间分辨率响应 24 分钟 OGD 的外排曲线表明，D-丝氨酸的外排略先于 L-谷氨酸一个 2 分钟的采样间隔。因此，当 glu 释放时，两种共激动剂都可用于激活 NMDA 受体。然而，D-丝氨酸外排相对于基线值的幅度小于 L-谷氨酸。OGD 期间的外排峰值（以 OGD 前基线值表示）如下：D-丝氨酸 254% +/- 24%，L-谷氨酸 1675% +/- 259%，L-天冬氨酸 519% +/- 128%，L-苏氨酸 313% +/- 33%。OGD 时 L-谷氨酰胺的外排明显减少。微灌注/CE-LIF 方法显示出几种有前途的属性，可用于研究单个急性脑片中的内源性化学外排。
