Hertz L, Murthy C R, Lai J C, Fitzpatrick S M, Cooper A J
Neurochem Pathol. 1987 Feb-Apr;6(1-2):97-129. doi: 10.1007/BF02833602.
Some metabolic effects on primary cultures of neurons or astrocytes were studied following acute or chronic exposure to pathophysiological concentrations (usually 3 mM) of ammonia. Three parameters were investigated: (1) 14CO2 production from 14C-labeled substrates [glucose, pyruvate, branched-chain amino acids (leucine, valine, isoleucine), and glutamate]; (2) interconversion between glutamate and glutamine; and (3) incorporation of label from labeled branched-chain amino acids into proteins. Neither acute nor chronic exposure to ammonia had any effect on 14CO2 production from [U-14C]glucose in astrocytes and neurons, whereas under certain conditions 14CO2 production from [1-14C]pyruvate in astrocytes was inhibited by ammonia. Production of 14CO2 from [1-14C]branched-chain amino acids was inhibited by acute, but stimulated by chronic, exposure to ammonia (3 mM) in astrocytes, with less effect in neurons. Production of 14CO2 from [1-14C]glutamate in both astrocytes and neurons was inhibited by acute exposure to ammonia. In astrocytes, glutamate levels tended to decrease and glutamine levels tended to increase following acute exposure to ammonia; in neurons, both glutamine and glutamate levels decreased. Protein content (per culture dish) increased in astrocytes but not in neurons, after chronic exposure to ammonia, possibly as a result of enhanced protein synthesis and/or by inhibition of protein degradation.
在原代培养的神经元或星形胶质细胞急性或慢性暴露于病理生理浓度（通常为3 mM）的氨后，研究了其一些代谢效应。研究了三个参数：（1）14C标记底物[葡萄糖、丙酮酸、支链氨基酸（亮氨酸、缬氨酸、异亮氨酸）和谷氨酸]产生的14CO2；（2）谷氨酸和谷氨酰胺之间的相互转化；（3）标记的支链氨基酸中的标记掺入蛋白质。急性或慢性暴露于氨对星形胶质细胞和神经元中[U-14C]葡萄糖产生的14CO2均无影响，而在某些条件下，氨可抑制星形胶质细胞中[1-14C]丙酮酸产生的14CO2。急性暴露于氨可抑制星形胶质细胞中[1-14C]支链氨基酸产生的14CO2，但慢性暴露（3 mM）则会刺激其产生，对神经元的影响较小。急性暴露于氨可抑制星形胶质细胞和神经元中[1-14C]谷氨酸产生的14CO2。在星形胶质细胞中，急性暴露于氨后谷氨酸水平趋于下降，谷氨酰胺水平趋于上升；在神经元中，谷氨酰胺和谷氨酸水平均下降。慢性暴露于氨后，星形胶质细胞中的蛋白质含量（每个培养皿）增加，而神经元中则没有增加，这可能是由于蛋白质合成增强和/或蛋白质降解受到抑制所致。
