Lewin L, Mattsson M O, Sellström A
Department of Cellular and Developmental Biology, Umeå University, Sweden.
Neurochem Res. 1996 Jan;21(1):79-85. doi: 10.1007/BF02527675.
Primary neuronal cultures were made from eight-day-old embryonic chick telencephalon. Ten-day-old cultures were used to study the release of D-[3H]aspartate and L-[3H]glutamate. The D[3H]aspartate release was stimulated by increasing potassium concentrations, but it was not calcium dependent. In contrast, the potassium dependent L-[3H]glutamate release was calcium dependent, and furthermore L-[3H]glutamate release was optimal at potassium concentrations < 30 mM. The inhibitors of glutamate uptake, dihydrokainate and 1-aminocyclobutane-trans-1,3-dicarboxylic acid (CACB), also referred to as cis-1 -aminocyclobutane-1,3-dicarboxylate, were used in the release experiments. Dihydrokainate had no effect on aspartate release, whereas CACB increased both the basal efflux of D-[3H]aspartate and the potassium evoked release. CACB had no effect on the potassium stimulated L-glutamate release. We believe that L-glutamate is released mainly by a vesicular mechanism from the presumably glutamatergic neurons present in our culture. D-aspartate release observed by us, could be mediated by a transporter protein. The cellular origin of this release remains to be assessed.
原代神经元培养物取自8日龄鸡胚端脑。使用10日龄培养物研究D-[3H]天冬氨酸和L-[3H]谷氨酸的释放。增加钾浓度可刺激D-[3H]天冬氨酸的释放，但它不依赖于钙。相反，依赖钾的L-[3H]谷氨酸释放依赖于钙，而且L-[3H]谷氨酸释放在钾浓度<30 mM时最为显著。在释放实验中使用了谷氨酸摄取抑制剂二氢海因酸和1-氨基环丁烷-反式-1,3-二羧酸（CACB），也称为顺式-1-氨基环丁烷-1,3-二羧酸。二氢海因酸对天冬氨酸释放无影响，而CACB增加了D-[3H]天冬氨酸的基础外流以及钾诱发的释放。CACB对钾刺激的L-谷氨酸释放无影响。我们认为L-谷氨酸主要通过囊泡机制从我们培养物中可能存在的谷氨酸能神经元释放。我们观察到的D-天冬氨酸释放可能由转运蛋白介导。这种释放的细胞来源仍有待评估。
