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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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Citing This Article：

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).