早期经验对大鼠脑区一氧化氮合酶活性的影响

目的　探讨NO与早期饲养环境所引起脑效应的关系。方法　将断乳大鼠在丰富环境 (EC)和单调环境 (IC)中饲养 30d。环境暴露后通过NADPH -黄递酶组化方法对海马齿状回 (DEN)和大脑皮层NOS活性进行定量测定以及对大鼠进行Morris水迷宫作业训练。结果　EC大鼠与IC大鼠相比 ,海马齿状回 (DEN)和大脑皮层NOS活性明显下降 ,迷宫测试表明EC大鼠的空间认知显著优于IC大鼠。在环境暴露期间隔日注射一氧化氮合酶 (NOS)抑制物L -NAME(50mg/kg) ,未引起EC或IC大鼠认知行为的明显改变 ,但导致DEN和大脑皮层NOS活性的不同改变。结论　NO可能与早期经验脑效应有关。

The Effects of Early Experiences on Nitric Oxide Synthase Activity in the Rat Brain

Objective To observe the relationship between nitric oxide(NO) and the cerebral effects of rearing environments in early life Methods The weaning rats were raised either in enriched environmental condition (EC) or in impoverished environmental condition (IC).After exposure,NO synthase (NOS) activity of the hippocampal dentate and cortex was determined quantitatively using NADPH-diphorase histochemistry and Morris maze tasks were tested for each group. Results NOS activity in both dentate gyrus of hippocampus (DEN) and cortex was significantly lowered in EC rats than in IC rats,and the EC rats showed improved spatial cognitive ability as compared to IC rats Conclusions This results suggested that the possible involvement of NO in the cerebral effects of early experience. Administration of L-NAME during environmental exposure failed to alter performances in maze tasks tested after exposure but resulted in lowered NOS activity in DEN and increased NOS activity in cortex.