Increased capacity and density of choline transporters situated in synaptic membranes of the right medial prefrontal cortex of attentional task-performing rats
Increased capacity and density of choline transporters situated in synaptic membranes of the right medial prefrontal cortex of attentional task-performing rats
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DOI：
10.1523/jneurosci.0205-05.2005
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发表时间：
2005-04-13
影响因子：
5.3
通讯作者：
Sarter, M
中科院分区：
文献类型：
--
作者：
Apparsundaram, S;Martinez, V;Sarter, M
支配皮层的胆碱能神经元已被概念化为大脑注意系统的主要组成部分。由于最近的证据表明调节胆碱转运蛋白（CHT）介导的高亲和力胆碱摄取（这是乙酰胆碱合成的限速步骤）的可塑性机制，本实验确定了胆碱能末梢转运胆碱的能力，以及位于突触末梢膜上的胆碱转运蛋白的比例，在执行认知警戒任务（CVT）和简单反应时间任务（SRTT）的大鼠和不执行（NP）大鼠的几个脑区域中。从NP大鼠的证据相比，增加胆碱转运能力[所示的最大转运速度（V-max）]和位于突触质膜的CHTs的密度增加，相对于细胞内的位置，观察到在内侧前额叶皮层的右，但不是左半球的CVT执行动物。此外，在信号试验中，CVT大鼠右内侧前额叶V-max值与动物的表现呈正相关，左内侧V-max值与动物的表现呈负相关。在SRTT执行动物的大脑中的CHT功能的措施没有显着不同的NP大鼠。目前的数据支持的假设，增加胆碱转运体在右内侧前额叶皮层的能力，主要是由于增加贩运的转运体从细胞内室的终端膜，代表一种细胞机制，有助于调解的注意力表现。
Cholinergic neurons innervating the cortex have been conceptualized as a major component of the attention system of the brain. Because of recent evidence indicating plastic mechanisms regulating choline transporter (CHT)-mediated high-affinity choline uptake, which is the rate-limiting step of acetylcholine synthesis, the present experiment determined the capacity of cholinergic terminals to transport choline, and the proportion of choline transporters localized in the membrane of synaptic terminals, in several brain regions of rats performing a cognitive vigilance task (CVT) and a simple reaction time task (SRTT) and nonperforming (NP) rats. Compared with evidence from NP rats, increased choline transporter capacity [as indicated by maximum transporter velocity (V-max)] and an increased density of CHTs situated in synaptic plasma membrane, relative to intracellular locations, were observed in the medial prefrontal cortex of the right but not left hemisphere of CVT-performing animals. Furthermore, right medial prefrontal V-max values of CVT-performing rats correlated positively and left medial V-max values correlated negatively with the animals' performance in signal trials. Measures of CHT function in the brains of SRTT-performing animals did not differ significantly from those in NP rats. The present data support the hypothesis that an increased capacity of choline transporters in the right medial prefrontal cortex, primarily attributable to increased trafficking of transporters from intracellular compartments to the terminal membrane, represents a cellular mechanism contributing to the mediation of attentional performance.