CHOLINE UPTAKE SYSTEMS OF RAT-BRAIN SYNAPTOSOMES
CHOLINE UPTAKE SYSTEMS OF RAT-BRAIN SYNAPTOSOMES
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DOI：
10.1016/0005-2736(73)90508-7
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发表时间：
1973-01-01
期刊：
影响因子：
--
通讯作者：
NODA, H
中科院分区：
文献类型：
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作者：
HAGA, T;NODA, H
[~3H]胆碱在突触体内的摄取和随后的[~3H]乙酰胆碱的合成与孵育液中胆碱、Na+和半胱氨酸-3的浓度有关。结果表明存在两种载体介导的胆碱摄取系统。一个系统需要Na+来吸收，另一个系统则不需要。Na+依赖系统进入突触体的胆碱有60%转化为乙酰胆碱，而Na+非依赖系统进入突触体的胆碱只有少部分转化为乙酰胆碱。Km，半最大转运的胆碱浓度：Na+依赖系统为4-8μM，非Na+非依赖系统为40μM。
The uptake of [3H]choline into synaptosomes and the subsequent synthesis of [3H]acetylcholine were examined as functions of choline, Na+and hemicholinium-3 concentrations in the incubation medium. The results indicate the presence of two carrier-mediated uptake systems for choline. One system requires Na+for the uptake and the other does not. About 60% of the choline taken up into synaptosomes by the Na+-dependent system were converted to acetylcholine, whereas only a few percent of the choline taken up into synaptosomes by the Na+-independent system were converted to acetylcholine.Km, the choline concentration giving half-maximum transport was 4–8 μM for the Na+-dependent system and about 40 μM for the Na+-independent system.Kivalues for hemicholinium-3 were 0.05–0.1 μM for the Na+-dependent system and 40–50 μM for the Na+-independent system.