Hassel B, Westergaard N, Schousboe A, Fonnum F
Norwegian Defense Research Establishment Division for Environmental Toxicology, Kjeller, Norway.
Neurochem Res. 1995 Apr;20(4):413-20. doi: 10.1007/BF00973096.
Astrocytes and neurons cultured from mouse cerebellum and cerebral cortex were analyzed with respect to content and synthesis of amino acids as well as export of metabolites to the culture medium and the response to fluorocitrate, an inhibitor of aconitase. The intracellular levels of amino acids were similar in the two astrocytic populations. The release of citrate, lactate and glutamine, however, was markedly higher from cerebellar than from cortical astrocytes. Neurons contained higher levels of glutamate, aspartate and GABA than astrocytic cultures. Cortical neurons were especially high in GABA and aspartate, and the level of aspartate increased specifically when the extracellular level of glutamine was elevated. Fluorocitrate inhibited the TCA cycle in the astrocytes, but was less effective in cerebellar neurons. Whereas neurons responded to fluorocitrate with an increase in the formation of lactate, reflecting glycolysis, astrocytes decreased the formation of lactate in the presence of fluorocitrate, indicating that astrocytes to a high degree synthesize pyruvate and hence lactate from TCA cycle intermediates.
对从小鼠小脑和大脑皮层培养的星形胶质细胞和神经元进行了分析，内容涉及氨基酸的含量和合成、代谢产物向培养基的输出以及对氟柠檬酸（乌头酸酶抑制剂）的反应。在这两种星形胶质细胞群体中，氨基酸的细胞内水平相似。然而，小脑星形胶质细胞释放的柠檬酸、乳酸和谷氨酰胺明显高于皮层星形胶质细胞。神经元中谷氨酸、天冬氨酸和γ-氨基丁酸的水平高于星形胶质细胞培养物。皮层神经元中的γ-氨基丁酸和天冬氨酸含量尤其高，当细胞外谷氨酰胺水平升高时，天冬氨酸水平会特异性增加。氟柠檬酸抑制星形胶质细胞中的三羧酸循环，但对小脑神经元的作用较小。神经元对氟柠檬酸的反应是乳酸生成增加，这反映了糖酵解过程；而在氟柠檬酸存在的情况下，星形胶质细胞的乳酸生成减少，这表明星形胶质细胞在很大程度上从三羧酸循环中间体合成丙酮酸，进而合成乳酸。
