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#alpha#_(2A)肾上腺素受体激动剂guanfacine增强大鼠空间学习能力而不影响条件性恐惧记忆

金新春, 马朝林, 李葆明

复旦大学脑科学研究院神经生物学研究所.上海 200032

摘要

#alpha#_(2A)肾上腺素受体选择性激动剂guanfacine对空间工作记忆和选择性注意等前额叶皮层认知功能有重要的、有益的影响。然而，激活#alpha#_(2A)受体对于依赖杏仁体和海马回路的恐惧记忆条件反射是否有影响，目前尚不清楚。该研究结果显示，全身给guanfacine显著提高大鼠在Lashley迷宫中的空间学习能力：guanfacine大鼠达到学会标准所需要的训练次数和所犯错误的次数显著少于生理盐水对照组大鼠。然而，guanfacine组大鼠场景和声音恐惧记忆的获得／巩固与对照组大鼠相比没有显著差异。结果提示，刺激#alpha#_(2A)受体产生的有益效应是任务依赖的：guanfacine改善空间学习能力，但不影响恐惧记忆的获得／巩固。

关键词： guanfacine; #alpha#_(2A)肾上腺素受体; 空间学习; 条件性恐惧记忆; 大鼠

The #alpha#_(2A)--adrenoceptor agonist guanfacine improves spatial learning but not fear conditioning in rats

Jin Xinchun, Ma Chaolin, Li Baoming

Institute of Neurobiology, Institutes of Brain Science,Fudan University.Shanghai 200032

Abstract

It is known that stimulation of the #alpha#_(2A)-adrenoceptors (#alpha#_(2A)-ARs) by the selective #alpha#_(2A)-AR agonist guanfacine produces an important and beneficial influence on prefrontal cortical （PFC） cognitive functions such as spatial working memory and selective attention. However, it is unclear whether stimulation of the #alpha#_(2A)-ARs has a similar effect on fear conditioning that involves the amygdala and hippocampus. Here, we show that systemically administered guanfacine significantly enhances spatial learning of rats in the Lashley maze： compared with controls, the rats treated with guanfacine required significantly fewer trials and made significantly fewer errors to reach learning criterion. However, guanfacine produced no effect on acquisition of contextual and auditory fear memories. The present study suggests that beneficial effect of #alpha#_(2A)-AR stimulation is task-dependent： guanfacine improves spatial learning but not fear conditioning.

Key words: guanfacine;#alpha#_(2A)-adrenoceptors;spatial learning;fear conditioning;Rats

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引用本文：

金新春, 马朝林, 李葆明. #alpha#_(2A)肾上腺素受体激动剂guanfacine增强大鼠空间学习能力而不影响条件性恐惧记忆[J]. 生理学报 2007; 59 (6): 739-744.

Jin Xinchun, Ma Chaolin, Li Baoming. The #alpha#_(2A)--adrenoceptor agonist guanfacine improves spatial learning but not fear conditioning in rats. Acta Physiol Sin 2007; 59 (6): 739-744 (in Chinese with English abstract).