Anderson R E, Hollyfield J G, Verner G E
Invest Ophthalmol Vis Sci. 1981 Oct;21(4):554-62.
Isolated retinas from Xenopus laevis tadpoles or juvenile frogs were incubated in Ringer's bicarbonate-glucose medium in which sodium chloride was replaced with equimolar amounts of either sodium aspartate (NaAsp) or sodium glutamate (NaGlu). At all concentrations tested (0.1 to 50 mM), both acidic amino acids caused a dramatic decrease in the incorporation of 3H-leucine into proteins in the inner retina. Higher concentrations of these acids (50 mM) caused an increase in the incorporation of the label by photoreceptors. Polyacrylamide gel disc electrophoresis of whole retinal proteins showed a selective increase in incorporation of the label into rhodopsin, a protein unique to rod photoreceptor cells. Quantitative autoradiographic and biochemical studies showed that NaAsp had no effect on the uptake of 3H-leucine by the retinal cells, suggesting that the effect is directly on protein synthesis. When retinas were removed from NaAsp treatment, protein synthetic capacity recovered. and the degree of recovery was related to the concentration of NaAsp in the preincubation medium. These studies demonstrate that acidic amino acids in concentration utilized in electrophysiologic studies to isolate the photoreceptor generated a-wave of the electroretinogram also have a profound effect on retinal protein synthesis. Whether these two actions are related remains to be determined.
将非洲爪蟾蝌蚪或幼蛙的分离视网膜置于林格氏碳酸氢盐 - 葡萄糖培养基中培养，该培养基中氯化钠被等摩尔量的天冬氨酸钠（NaAsp）或谷氨酸钠（NaGlu）取代。在所有测试浓度（0.1至50 mM）下，两种酸性氨基酸均导致内视网膜中3H - 亮氨酸掺入蛋白质的量显著减少。这些酸的较高浓度（50 mM）导致光感受器中标记物掺入量增加。全视网膜蛋白质的聚丙烯酰胺凝胶圆盘电泳显示，标记物掺入视紫红质（一种杆状光感受器细胞特有的蛋白质）的量有选择性增加。定量放射自显影和生化研究表明，NaAsp对视网膜细胞摄取3H - 亮氨酸没有影响，这表明该作用直接作用于蛋白质合成。当视网膜从NaAsp处理中取出时，蛋白质合成能力恢复，恢复程度与预孵育培养基中NaAsp的浓度有关。这些研究表明，在电生理学研究中用于分离视网膜电图光感受器a波的浓度的酸性氨基酸，也对视网膜蛋白质合成有深远影响。这两种作用是否相关仍有待确定。
