Peng L, Swanson R A, Hertz L
Hongkong DNA Chips, Kowloon, Hongkong, China.
Neurochem Int. 2001 Apr;38(5):437-43. doi: 10.1016/s0197-0186(00)00104-2.
The hypothesis was tested that oxidative metabolism, mainly fueled by glutamate itself, provides the energy for active, Na(+),K(+)-ATPase-catalyzed Na(+) extrusion following glutamate uptake in conjunction with Na(+). This hypothesis was supported by the following observations: (i) glutamate had either no effect or caused a slight reduction in glycolytic rate, measured as deoxyglucose phosphorylation; (ii) D-aspartate, which is accumulated by the L-glutamate carrier, but cannot be metabolized by the cells, caused an increase in glycolytic rate; (iii) monensin which, like D-aspartate, stimulates the intracellular, Na(+)-activated site of the Na, K-ATPase and thus energy metabolism, but provides no metabolic substrate, stimulated both glycolysis and glucose oxidation; and (iv) oxidation of glucose was potently inhibited by glutamate, although glutamate is known to stimulate oxygen consumption in primary cultures of astrocytes, a combination showing that oxidation of a non-glucose substrate is increased in the presence of glutamate. These findings should be considered in attempts to understand metabolic interactions between neurons and astrocytes and regulation of energy metabolism in brain.
有一个假说得到了验证，即主要由谷氨酸自身提供燃料的氧化代谢，为谷氨酸与钠离子协同摄取后由活性钠钾ATP酶催化的钠离子排出提供能量。以下观察结果支持了这一假说：（i）谷氨酸对以脱氧葡萄糖磷酸化衡量的糖酵解速率要么没有影响，要么使其略有降低；（ii）由L-谷氨酸载体积累但不能被细胞代谢的D-天冬氨酸会导致糖酵解速率增加；（iii）莫能菌素与D-天冬氨酸一样，刺激钠钾ATP酶的细胞内钠离子激活位点，从而促进能量代谢，但不提供代谢底物，它能同时刺激糖酵解和葡萄糖氧化；（iv）尽管已知谷氨酸能刺激星形胶质细胞原代培养物中的氧气消耗，但谷氨酸却能有效抑制葡萄糖的氧化，这一组合表明在有谷氨酸存在的情况下非葡萄糖底物的氧化会增加。在试图理解神经元与星形胶质细胞之间的代谢相互作用以及大脑中能量代谢的调节时，应考虑这些发现。
