Characterization of L-DOPA transport in cultured rat and mouse astrocytes
Characterization of L-DOPA transport in cultured rat and mouse astrocytes
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DOI：
10.1002/(sici)1097-4547(19960215)43:4
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发表时间：
1996-02-15
影响因子：
4.2
通讯作者：
Lee, EHY
中科院分区：
文献类型：
--
作者：
Tsai, MJ;Lee, EHY
本工作研究了L-多巴在培养的大鼠和小鼠星形胶质细胞中的转运。结果表明，L-[C-14]DOPA在大鼠和小鼠星形胶质细胞中的摄取均为非Na+依赖性和温度敏感性，并由载体介导的机制介导，其Km值分别为36和60.3 μ M，Vmax值分别为2.4和1.9 nmol/min/mg protein。有趣的是，细胞内L-[C-14]DOPA的释放也被影响L-DOPA摄取的竞争者反式刺激，在2 min摄取过程中回收的C-14被鉴定为L-[C-14]DOPA，然而，在L-DOPA孵育30分钟后，在大鼠和小鼠星形胶质细胞中也检测到[C-14]多巴胺（DA），表明芳香族L-氨基酸脱羧酶（AADC）的存在。L-DOPA通过一种不依赖于Na+的转运体向大鼠和小鼠星形胶质细胞中转运，并优先转运芳香族和支链氨基酸，大鼠星形胶质细胞对L-DOPA的亲和力高于小鼠星形胶质细胞，两种细胞均能从外源性L-DOPA合成DA，因此，星形胶质细胞不仅作为L-DOPA的临时储存部位，而且作为DA产生机器，这些结果对于L-DOPA药物治疗下的帕金森病患者可能特别重要。(C)1996 Wiley-Liss，Inc.
The present work studied the transport of L-DOPA in cultured rat and mouse astrocytes. Results indicated that the uptake of L-[C-14]DOPA in both rat and mouse astrocytes was Na+ independent and temperature sensitive, It was mediated by a carrier-mediated mechanism with K-m values of 36 and 60.3 mu M, and V-max values of 2.4 and 1.9 nmol/min/mg protein for rat and mouse cells, respectively. L-DOPA uptake was potently inhibited by aromatic or branched-chain amino acids, Interestingly, the release of intracellular L-[C-14]DOPA was also trans stimulated by competitors that affect L-DOPA uptake, The C-14 recovered in the 2-min uptake process was identified as L-[C-14]DOPA, However, [C-14]dopamine (DA) was also detected in both rat and mouse astrocytes after 30 min L-DOPA incubation, indicating the existence of aromatic L-amino acid decarboxylase (AADC), Taken together, L-DOPA was uphill transported into rat and mouse astrocytes by a Naf-independent exchanger with preference for aromatic and branched-chain amino acids, Rat astrocytes possessed higher affinity for L-DOPA uptake than mouse astrocyte, Both cells synthesized DA from exogenous L-DOPA, Thus, astrocytes serve not only as a temporary storage site for L-DOPA but also as a DA-producing machinery, These results may be of particular importance to parkinsonian patients under L-DOPA medication. (C) 1996 Wiley-Liss, Inc.