摘要
采用避暗回避反应实验和免疫细胞化学相结合的方法 ,选用 5个实验组 (即 :空白对照组、实验对照组、假训练组、训练组和记忆唤酲组 ) ,对不同月龄大鼠背海马结构中的 c- Fos表达进行了观察。结果发现 :老年大鼠在避暗回避训练中 ,探索次数多于青年和成年大鼠 ,且滞留时间明显缩短 ;成年和老年大鼠在训练、假训练和记忆唤醒后 ,背海马内 c- Fos的表达明显低于青年组大鼠 ,以训练组最为显著。该结果一方面表明随年龄的增长 ,海马神经元对应激和学习记忆尤其是后者的反应性降低 ;
With dark avoidance task and immunocytochemical method,the present study investigated the c Fos expression in dorsal hippocampal formation of different age rats in five experimental groups(passive control group,active control group,training group,pseudotraining group and memory arousing group).The results are as follows:①At first,the retention of learning behavior was compared in different age groups with dark avoidance task respectively.The mean exploring time(3 70 times±0 34 times, n =10)was more and the mean latency (3 30 min±2 99 min, n =5)was shorter in old group than that in young group (2 60 times ±0 16 times and 12 20 min±1 83 min)and adult group (2 30 times±0 21times and 12 00 min±1 38 min).This indicated that the ability of learning and memory decreased in the old rats;②In passive control(rats remained in their home cage)and active control(rats remained in goal box for 15 min without foot shock)groups,very few Fos positive neurons were seen in dorsal hippocampus in each age group.No diffference was found between them( P >0 05);③In adult and old rats,the pseudotraining ,training and especially the memory arousing induced,the number of c Fos positive neurons was less than that in young rats.This indicated that the responding ability of hippocampal neurons to learning and stress stimulation decreased.And the result also suggested that number of hippocampal neurons may reduce in adult and old rats.
