Cocaine induction of dopamine transporter trafficking to the plasma membrane
Cocaine induction of dopamine transporter trafficking to the plasma membrane
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DOI：
10.1124/mol.61.2.436
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发表时间：
2002-02-01
影响因子：
3.6
通讯作者：
Zhang, L
中科院分区：
文献类型：
--
作者：
Little, KY;Elmer, LW;Zhang, L
先前的几项人体死后实验已经检测到慢性可卡因使用者纹状体[H-3]WIN 35428与多巴胺转运蛋白（DAT）结合的增加。然而，动物实验已经发现可卡因给药后脑中DAT放射性配体结合水平的相当大的变化，这可能是由治疗的长度和剂量以及所用放射性配体的类型引起的。目前的实验测试的假设，[H-3]WIN 35428的结合和[H-3]多巴胺摄取将增加暴露于可卡因通过DAT细胞运输的改变，而不是增加蛋白质合成。在稳定hDAT转染的N2 A细胞中进行实验，并评估可卡因对[H-3]WIN 35428与DAT结合、[H-3]多巴胺摄取、DAT蛋白和mRNA测量以及DAT亚细胞定位的剂量反应和时间过程影响。10（-6）M剂量的可卡因分别在12和3小时后导致[H-3]WIN 35428结合和[H-3]多巴胺摄取的统计学显著增加。尽管DAT功能增加，但DAT总蛋白或mRNA没有变化。免疫荧光和生物素化实验表明，可卡因治疗引起质膜DAT免疫反应性增加和细胞内减少。本模型系统可能进一步我们的理解DAT放射性配体结合和可卡因暴露引起的功能的调节改变。
Several previous human postmortem experiments have detected an increase in striatal [H-3]WIN 35428 binding to the dopamine transporter (DAT) in chronic cocaine users. However, animal experiments have found considerable variability in DAT radioligand binding levels in brain after cocaine administration, perhaps caused by length and dose of treatment and type of radioligand used. The present experiments tested the hypothesis that [H-3]WIN 35428 binding and [H-3]dopamine uptake would be increased by exposure to cocaine through alterations in DAT cellular trafficking, rather than increased protein synthesis. Experiments were conducted in stably hDAT-transfected N2A cells and assessed the dose response and time course of cocaine effects on [H-3]WIN 35428 binding to the DAT, [H-3]dopamine uptake, measures of DAT protein and mRNA, as well as DAT subcellular location. Cocaine doses of 10(-6) M caused statistically significant increases in [H-3]WIN 35428 binding and [H-3]dopamine uptake after 12 and 3 h, respectively. Despite these increases in DAT function, there was no change in DAT total protein or mRNA. Immunofluorescence and biotinylation experiments indicated that cocaine treatment induced increases in plasma membrane DAT immunoreactivity and intracellular decreases. The present model system may further our understanding of regulatory alterations in DAT radioligand binding and function caused by cocaine exposure.