星形神经胶质细胞摄取谷氨酸与环境因子和离子运输的关系

本文以星形神经胶质细胞为对象,用同位素示踪技术较详细地研究了介质中Na、、K~+和CL~-、不同浓度的卡因酸以及几种抑制剂对L-谷氨酸摄取的影响;并观察了L-谷氨酸对星形神经胶质细胞膜运输Na~+、K~+、Cl~-和Ca~(2+)等的作用.结果表明:L-谷氨酸的摄取依赖于介质中是否存在Na~+ ,在缺Na~+介质中对Cl~-的依赖性也较明显,但在正常Na~+浓度下,含Cl~_和缺Cl~_没有明显差别.当增加介质中K~+浓度引起膜的去极化时,则能降低L~_谷氨酸的摄取.反过来,L-谷氨酸的摄取也对Na~+、K~+、Cl~-等的运输起刺激作用.此外,卡因酸及所用的几种抑制剂对谷氨酸的摄取办有明显抑制作用.

STUDIES OF RELATIONS OF GLUTAMATE UPTAKE BY ASTROCYTE WITH ENVIROMENT FACTORS AND ION TRANSPORT

Astrocyte cultures and radioisotopic tracer method were used in this study. The effects of ions (Na-, K+, Cl-), of different concentration of kainic acidand of some inhibitors in media on uptake of L-glutamate and influence of L-glutamate uptake on Na+, K+, Cl-, Ca2+ ion transport on cell membrane were explored. The results suggest that the uptake of L-glutamate depended on the concentration of Na + . Also, it depended obviously on concentration of Cl- in the absence of Na+ in media, but not in the pre-sence of phsiological concentration of Na + . The glutamate uptake was decreased when K- concentration was increased which caused depolarization. On the other hand, glutamate uptake stimulated the transports of Na+, K+, Cl-. The results also show that uptake of glutamate was inhibited by 10-3 or 10-2 M Kainic acid and the inhibitors used.