Korpi E R
Neurochem Res. 1980 Apr;5(4):415-31. doi: 10.1007/BF00964230.
Tryptophan and phenylalanine transport in rat cerebral cortex slices was studied in sodium-free media and during influx and efflux of sodium ions. Choline as a substitute for sodium in incubation media increased efflux and decreased influx of tryptophan and phenylalanine. Exchange of intracellular [3H]tryptophan and [3H]phenylalanine with extracellular unlabeled histidine, phenylalanine, and tryptophan was sodium-independent. Efflux of sodium ions from the slices had no immediate effects on phenylalanine and tryptophan efflux, but influx decreased. Influx of sodium into the sodium-depleted slices provoked a transient increase in tryptophan and phenylalanine efflux and also enhanced influx. The results are interpreted to indicate that sodium ions may possibly affect the function of the primary transport sites for aromatic amino acids at cerebral membranes by controlling the orientation of their reactive sites towards the intracellular and extracellular sides, rather than by being directly involved in the binding of amino acids to the carriers.
在无钠培养基以及钠离子流入和流出的过程中，对大鼠大脑皮层切片中的色氨酸和苯丙氨酸转运进行了研究。在孵育培养基中，用胆碱替代钠会增加色氨酸和苯丙氨酸的流出并减少其流入。细胞内的[3H]色氨酸和[3H]苯丙氨酸与细胞外未标记的组氨酸、苯丙氨酸和色氨酸的交换不依赖于钠。切片中钠离子的流出对苯丙氨酸和色氨酸的流出没有立即影响，但流入减少。钠离子流入缺钠切片会引起色氨酸和苯丙氨酸流出的短暂增加，同时也增强了流入。结果表明，钠离子可能通过控制其反应位点朝向细胞内和细胞外侧的方向来影响大脑膜上芳香族氨基酸初级转运位点的功能，而不是直接参与氨基酸与载体的结合。
