Functional characterization of Na+-independent choline transport in primary cultures of neurons from mouse cerebral cortex
Functional characterization of Na+-independent choline transport in primary cultures of neurons from mouse cerebral cortex
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DOI：
10.1016/j.neulet.2005.09.069
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发表时间：
2006-01-30
影响因子：
2.5
通讯作者：
Yamamoto, A
中科院分区：
文献类型：
--
作者：
Fujita, T;Shimada, A;Yamamoto, A
本文报道了原代培养的小鼠大脑皮层神经元Na+非依赖性胆碱转运系统的功能特点。Na+非依赖性胆碱转运是饱和的米氏常数（K-t）为26.7 +/- 1.2 μ M和1.04 +/- 0.02 nmol/mg蛋白质/10分钟的最大速度（V-max）。胆碱摄取细胞外pH值和膜去极化的显着影响。该摄取系统被各种有机阳离子抑制，包括未标记的胆碱、胍、苯海拉明和胆碱类似物hemicholinium-3。然而，原型的有机阳离子四乙铵和西咪替丁表现出非常小的亲和力的Na+非依赖性胆碱摄取系统的神经元。这些结果表明，小鼠大脑皮层神经元表达的Na+非依赖性，高亲和力的胆碱转运系统。RT-PCR结果显示，胆碱转运体样蛋白1（choline transporter-like protein 1，CTL 1）及其剪接体CTL 1a在小鼠大脑皮层神经元中表达，CTL 1a是一种新型的Na+非依赖性胆碱转运体。胆碱在小鼠神经元中的Na+非依赖性转运特性与CTL 1和/或CTL 1a相似或相同。胆碱转运系统不仅与神经元生理学有关，而且与重要的有机阳离子药物的摄取有关。(c)2005爱思唯尔爱尔兰有限公司保留所有权利。
We report here the functional characteristics of Na+-independent choline transport system in primary cultures of neurons from mouse cerebral cortex. Na+-independent choline transport was saturable with a Michaelis constant (K-t) of 26.7 +/- 1.2 mu M and a maximal velocity (V-max) of 1.04 +/- 0.02 nmol/mg protein/10 min. Choline uptake was significantly influenced by extracellular pH and by membrane depolarization. This uptake system was inhibited by various organic cations including unlabeled choline, guanidine, diphenhydramine and the choline analog hemicholinium-3. However, the prototypical organic cation tetraethylammonium and cimetidine showed very little affinity for the Na+-independent choline uptake system in neurons. These results indicate that mouse cerebrocortical neurons express a Na+-independent, high-affinity choline transport system. RT PCR revealed that choline transporter-like protein 1 (CTL1) and its spliced variant CTL1a, which have been reported to be novel Na+-independent choline transporter, are expressed in mouse cerebrocortical neurons. The Na+-independent transport properties of choline in mouse neurons is similar or identical to that of CTL1 and/or CTL1a. This choline transport system seems to have relevance not only for neuronal physiology but also for the uptake of pharmacologically important organic cation drugs. (c) 2005 Elsevier Ireland Ltd. All rights reserved.