慢性锂处理对大鼠海马NOS表达的影响

目的　 探讨不同浓度氯化锂对大鼠海马一氧化氮合酶 (NOS)活性和神经元型一氧化氮合酶 (nNOS)蛋白表达的影响 ,阐明锂对学习记忆的影响与NOS表达的关系。方法　将大鼠随机分为对照 (Cont)组和四个氯化锂(LiCl) (3,30 ,30 0 ,30 0 0mg/kg)组 ,分别给予普通饲料和含LiCl(3,30 ,30 0 ,30 0 0mg/kg)的饲料喂养 6 0d ,通过Y -迷宫实验 ,比较各组大鼠学习记忆能力的差别 ;采用黄递酶 (NADPH d)组织化学染色和ABC免疫组织化学染色方法观察各组大鼠海马CA1区、CA3区和齿状回 (DG)一氧化氮合酶 (NOS)与nNOS阳性细胞数的差别。 结果　3,30mg/kgLiCl组大鼠Y 迷宫实验成绩明显好于正常对照组 (P <0 .0 1) ;30 0 ,30 0 0mg/kgLiCl组大鼠则明显差于对照组 (P <0 .0 5 )。NADPH d和ABC免疫组织化学染色结果示 :LiCl(3,30mg/kg)组大鼠海马NOS与nNOS阳性细胞数明显多于Cont组 (P <0 .0 5 ) ;LiCl(30 0 ,30 0 0mg/kg)组大鼠NOS与nNOS阳性细胞数少于Cont组 ,差异有显著性 (P <0 .0 5 )。 结论　 较低浓度的氯化锂能提高大鼠的学习记忆能力 ,增强NOS活性和nNOS蛋白表达 ,而较高浓度的锂则可能减低大鼠学习记忆能力 ,降低NOS活性和nNOS蛋白表达。

Effects of lithium on the nitric oxide synthase expression in the rat hippocampus

Objective To investigate the effects of lithium on the learning and memory, we studied the effects of lithium on the activation of neuronal nitric oxide synthase on rat hippocampus. Methods Wistar rats were randomly divided into control group, four lithium chloride(LiCl)(3, 30, 300, 3000 mg/kg)-treated groups. Four LiCl-treated groups were fed with food containing 3, 30, 300, 3000 mg/kg LiCl respectively. Sixty days latter, we compared the learning ability and memory capacity through Y-maze test, and examined the NOS and nNOS-positive neurons in CA1, CA3 and dentate gyrus by means of NADPH-diaphorased (NADPH-d) histochemistry and ABC immunity histochemistry. Rusults Y-maze: The training times of 3, 30mg/kg LiCl groups are fewer than control rats(P<0.01). However, the 300, 3000 mg/kg LiCl-treated groups were more (P<0.05). The number of NOS and nNOS-positive neurons in LiCl(3, 30 mg/kg)-treated groups were greater than control group(P<0.05). The number of NOS and nNOS-positive neurons of LiCl(300, 3000 mg/kg)-treated groups were smaller than control group(P<0.05).Conclusion Low dose of lithium improved the ability of learning and memory, and enhanced the expression of NOS; High dose of lithium had the opposite effects.