褪黑素对大鼠空间学习记忆的影响及其机制研究  

Role of melatonin in spatial learning and memory in rats and its mechanism

作　　者：冯寅[1] 张烈雄[2] 晁东满[3] 

机构地区：[1]复旦大学医学院神经生物学教研室,上海200032 [2]华东师范大学生命科学学院生理学教研室,上海200062 [3]复旦大学医学院生理学教研室,上海200032

出　　处：《生理学报》2002年第1期65-70,共6页Acta Physiologica Sinica

摘　　要：本研究运用Morris水迷宫和电生理学方法 ,以逃避潜伏期、穿环系数和海马CA1区突触长时程增强(long termpotentiation ,LTP)为指标 ,研究褪黑素对大鼠空间学习记忆能力的影响。实验结果显示 :( 1)在Morris水迷宫 6d训练中 ,对照组大鼠后 4d平均逃避潜伏期为 18 4 4± 2 7s,褪黑素组为 3 0 0 2± 3 6s,两者有显著差异 (P <0 0 1) ;训练 6d后 ,褪黑素组穿环系数为 2 5 68± 2 3 2 % ,明显小于对照组的 4 3 3 3± 2 85 % (P <0 0 1)。( 2 )采用微量注射法给予海马CA1区褪黑素 ,强直后 60min ,fEPSP斜率为基准值的 114 2 8± 1 80 % ,显著低于对照组的 169 71±6 4 8% (P <0 0 1)。( 3 )预先给予东莨菪碱 ,不影响褪黑素对海马CA1区LTP的抑制 ,强直后 60minfEPSP斜率为基准值的 113 70± 5 5 5 %。( 4 )提前给予荷包牡丹碱后给予褪黑素 ,强直后 60minfEPSP斜率为基准值的 162 2 9±10 5 2 % ,明显大于褪黑素组 (P <0 0 1) ,而与对照组无显著差异 (P >0 0 5 )。上述结果表明 ,褪黑素对大鼠的空间学习记忆能力及海马CA1区LTP均有明显的抑制作用 ,两者相关 ;东莨菪碱不能阻断褪黑素对海马CA1区LTP的抑制作用 ,而荷包牡丹碱可以阻断褪黑素对LTP的抑制 。It has been suggested that melatonin is involved in learning and memory In the present study, we investigated the effects of melatonin on spatial learning and memory in rats, using Morris water maze and electrophysiological methods The results are as follows. (1) During a six day water maze training, the mean escape latency of melatonin group in the last 4 days was 30 02±3 6 s, and that of control group was 18 44±2 7 s ( P <0 01) The crossing annulus coefficient of melatonin group was 25 68±2 32%, and that of control group was 43 33±2 85% ( P <0 01) (2) Microinjection of melatonin into CA1 area inhibited long term potentiation (LTP) Sixty minutes after tetanus, the field excitory postsynaptic potentials (fEPSP) slope of group C ( n =7, 0 5 μl saline) was 169 71±6 48% of the baseline, and that of group M2 ( n =6, 2 μg melatonin) was 114 28±1 80% of the baseline The difference is significant ( P <0 01) (3) We also investigated the effects of melatonin on LTP after administration of scopolamine Sixty minutes after tetanus, the fEPSP slope of group SM ( n =6, 2 μg scopolamine before 2 μg melatonin) was 113 70±5 55% of the baseline. It showed a significant decrease compared with group C ( P <0 01) However , there was no difference between groups SM and M2 ( P >0 05, i v ). The results obtained by applying melatonin after bicuculline were different from those after scopolamine. Sixty minutes after tetanus, the fEPSP slope of group BM ( n =7, 1 μg bicuculline before 2 μg melatonin) was 162 29±10 52% of the baseline Compared with group C, there is no significant difference ( P >0 05); but compared with group M2, the difference is significant ( P <0 01) Our results showed that application of melatonin in rats significantly inhibited not only spatial learning and memory, but also LTP in CA1 area Furthermore, the results indicates that the inhibition of LTP by melatonin may not be mediated by choli

关 键 词：褪黑素 空间学习记忆 长时程增强 东莨菪碱 荷包牡丹碱 机制 大鼠 

分 类 号：R338.64[医药卫生—人体生理学]