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[Experiment-time affects the cognitive behavior in aged Sprague-Dawley rats.] [Ariticle in Chinese]

DENG Shi-Ning, SI Wen, SUN Li-Juan, ZENG Qing-Wen^*, CAO Xiao-Hua^*

Shanghai Key Laboratory of Brain Functional Genomics, Key Laboratory of Brain Functional Genomics of Ministry of Education, East China Normal University, Shanghai 200062, China

Abstract

In order to investigate if the experiment-time affects cognitive performance in aged rats in different learning and memorybehavioral tests, the aged Sprague-Dawley (SD) rats were divided into two groups randomly and subjected to open field test, Morriswater maze test and social discrimination test. The experiment of one group was conducted in 8:00 - 11:00 AM (AM group), and theother group in 15:00 - 18:00 PM (PM group). PM group exhibited higher locomotor activity than AM group in the open field test.Compared with AM group rats, PM group rats had significantly shorter swimming distance and escape latency to find the platform inMorris water maze training session, but no significant difference in the swimming velocity was observed between the two groups. Andin probe-test, PM group spent more time in target quadrant than AM group. These results revealed that PM group showed betterspatial learning and memory abilities than AM group. However, there was no significant difference between the two groups in socialinvestigation index in social discrimination test. These results show that experiment-time may affect cognitive performance in Morriswater maze but not in social discrimination task in aged rats. And the results indicate that experiment-time affects cognitive performanceof aged rats selectively in different learning and memory behavioral tasks.

Key words: aged rats; learning and memory; open field; Morris water maze; social discrimination

Received: 2010-02-23　　Accepted: 2010-03-26

Corresponding author: 曾庆文,曹晓华　　E-mail: qwzeng@brain.ecnu.edu.cn,xhcao@brain.ecnu.edu.cn

Citing This Article：

DENG Shi-Ning, SI Wen, SUN Li-Juan, ZENG Qing-Wen, CAO Xiao-Hua. [Experiment-time affects the cognitive behavior in aged Sprague-Dawley rats.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (3): 231-236 (in Chinese with English abstract).