去松果体对大鼠学习能力及大脑皮质NOS表达的影响

Effects of pinealectomy on the learning abilities and the expression of nitric oxide synthase in cerebral cortex of rats

目的 探讨去松果体后其功能减退致褪黑素 (MT)分泌减少对大鼠学习能力及大脑皮质一氧化氮合酶 (NOS)表达的影响。方法 将大鼠进行 Y型迷宫测试 ,淘汰学习障碍的大鼠 ,将学习正常的大鼠随机分二组 ,实验组手术摘除松果体 ,对照组给予假手术 ,饲养 40天后再行 Y型迷宫测试 ,SABC法检测神经元型一氧化氮合酶 (n NOS)表达。结果 实验组大鼠学习能力明显低于对照组大鼠 (P<0 .0 1) ,而大脑皮质、内侧隔核 -斜角带核 (SM- DB) n NOS免疫反应阳性细胞增多 ,与对照组相比分别为 P<0 .0 5、P<0 .0 1,纹状体、海马与对照组相比 n NOS阳性细胞无明显差别 ,均 P>0 .0 5。结论 大鼠松果体摘除可以引起大鼠学习能力障碍 ,其原因可能与大脑皮质、SM- DB n NOS过度表达 ,引起 NO神经毒性有关。

Objective To investigate the effects of decreased secretion of melatonin(MT) caused by pinealectomy on the learning abilities and the expression of nitric oxide synthase (NOS) in cerebral cortex of rats.Methods The rats were divided into two groups randomly after tested by Y type maze and those with learning dysfunction were eliminated,the experimental group was treated by pinealectomy, the control group was given sham operation. The rats were tested by Y type maze after fed for forty days and the expression of neuronal nitric oxide synthase (nNOS) was tested by SABC method.Results The learning abi lities of the experimental group were significant lower than those of the control rats ( P <0 01), nNOS positive cell in neocortex and medial septal nucleus diagonal band nucleus (SM DB) were more than that of control rats ( P <0.05 and P <0.01 respectively ),but there was no significant difference between the experimental group and the control rats in nNOS positive cell quantity of corpus striatum and hippocampus ( P >0.05).Conclusion Pinealectomy might cause the disorder of learning abilities in the rats,it might correlate with NO neurotoxicity arose by over expression nNOS in cerebral cortex and SM DB.