阻断一氧化氮形成对大鼠海马和大脑皮层由行为训练诱发的生长抑素mRNA表达的影响(英文)

用水迷宫和一次性被动回避反应两种行为学训练方法 ,结合脑室内注射一氧化氮合酶 (NOS)抑制剂 NAME(Nω-nitro-L -arginine)和原位杂交技术 ,观察了阻断 NOS前后大鼠海马和大脑皮层前额叶等区域由行为学训练诱发的生长抑素 (somatostatin,SOM) m RNA阳性细胞数量的改变。结果显示 :(1)同未经训练的对照组相比 ,两种行为学训练都引起海马和大脑皮层中 SOMm RNA阳性细胞的显著增加 ;(2 )在脑室中注射了 NAME的实验组动物 ,两种行为学训练都不能再诱发上述阳性细胞的增加 ,同时NAME也阻止了训练组出现的学习和记忆的形成。以上结果提示 ,一氧化氮参与了作为脑内学习和记忆神经化学基础之一的生长抑素表达增加的调控

BLOCKAGE OF NITRICOXIDE FORMATION AFFECTS EXPRESSION OF SOMATOSTATIN mRNA IN HIPPOCAMPUS AND CEREBRAL CORTEXFOLLOWING BEHAVIORAL TRAININGS IN RATS:AN IN SITU HYBRIDIZATION STUDY

The effects of nitric oxide(NO) on expression of somatostatin (SOM) messenger RNA (mRNA) following trainings of the Morris water maze task or one-trial passive avoidance test were investigated in rats by using in situ hybridization technique. Intracerebroventricular (i.c.v.) injection of saline vehicle or of 5 μmol Nω-nitro-L-arginine (NAME), an inhibitor of NO synthase, were given by appropriate schedules before two types of trainings and the changes in number of SOM mRNA positive neurons were examined in hippocampus and cerebral cortex. The results showed that: (1) when compared with non-trained control group, the number of SOM mRNA positive neurons were significantly increased in these two brain regions in rats that had been trained with either of two trainings; (2) the increase of SOM mRNA positive neurons in both regions following behavioral trainings could be significantly blocked by i.c.v. injection of NAME, and the injection also impaired the learning and memory formation as compared to that in control groups with trainings only. These data indicate that endogenous NO is critical for the formation of learning and memory, and also for the enhanced SOM mRNA expression that accompanies relevant behavioral trainings. It is proposed that NO might be involved in the cascade of central neurochemical changes, including the induction of somatostatin synthesis in related brain areas that underlie the learning and memory processes.