Morales-Delgado Nicanor, Popović Natalija, De la Cruz-Sánchez Ernesto, Caballero Bleda María, Popović Miroljub
Department of Human Anatomy and Psychobiology, Faculty of Medicine, University of Murcia, Murcia, Spain.
Institute of Biomedical Research of Murcia (IMIB), Virgen de la Arrixaca University Hospital, University of Murcia, Murcia, Spain.
Front Behav Neurosci. 2018 Dec 6;12:304. doi: 10.3389/fnbeh.2018.00304. eCollection 2018.
The purpose of the present study was to establish the effect of daytime and aging on memory in rats in the Elevated Plus-Maze (EPM) test. Young (2-months) and aged (18-months) male Wistar rats were exposed to the EPM test, at the beginning, mid-time or at the end of the light period. On the acquisition trial, the animals were placed individually at the end of one of the open arms of the EPM and the latency to enter in the enclosed arms was registered (cut-off time 60 s). The test was repeated 24 h later on. A longer latency period to reach the enclosed arm indicated poor retention compared to significantly shorter latencies. There were no significant differences between groups on the acquisition trial. In all tested periods, the latency time on the 24 h retention trial was significantly shorter in the young rats compared to the old ones. Furthermore, in the early and mid-time period of the light period, the young rats showed significantly decreased transfer latency (TL) time on the 24 h retention trial in comparison with the acquisition trial. In the aged rats, the TL time on the 24 h retention trial was significantly longer at the end of the light period, in comparison to the two other testing periods. In conclusion, aging significantly affects memory and the more critical period for memory process in both young and old animals, particularly at the end of the light period of the circadian cycle.
本研究的目的是在高架十字迷宫（EPM）试验中确定白天和衰老对大鼠记忆的影响。将年轻（2个月）和老年（18个月）雄性Wistar大鼠在光照期开始、中期或结束时进行EPM试验。在习得试验中，将动物单独放置在EPM一个开放臂的末端，并记录进入封闭臂的潜伏期（截止时间60秒）。24小时后重复该试验。与明显较短的潜伏期相比，到达封闭臂的潜伏期较长表明记忆保持较差。在习得试验中，各组之间没有显著差异。在所有测试时间段内，年轻大鼠在24小时记忆保持试验中的潜伏期时间明显短于老年大鼠。此外，在光照期的早期和中期，年轻大鼠在24小时记忆保持试验中的转换潜伏期（TL）时间与习得试验相比显著缩短。在老年大鼠中，与其他两个测试时间段相比，光照期结束时24小时记忆保持试验中的TL时间明显更长。总之，衰老显著影响记忆，并且在年轻和老年动物中记忆过程的更关键时期，特别是在昼夜周期光照期结束时。
