大鼠视觉发育可塑性关键期终止前后视皮层神经元AMPA受体GluR2亚基表达的变化  

Developmental changes in expression of AMPA-receptor subunit GluR2 in rat visual cortex around termination of critical period

作　　者：王昌鹏[1] 阴正勤[1] 秦伟[1] 曾玉晓[1] 

机构地区：[1]第三军医大学西南医院/西南眼科医院,重庆市400038

出　　处：《眼科新进展》2008年第7期481-485,共5页Recent Advances in Ophthalmology

基　　金：国家自然科学基金资助(编号:30672280)~~

摘　　要：目的为了探索视觉发育可塑性关键期终止机制,在可塑性关键期终止前后,对正常大鼠视皮层内AMPA受体GluR2亚基表达的发育变化进行了研究。方法用免疫荧光标记技术,标记生后3-8周的正常大鼠视皮层内AMPA受体GluR2亚基表达。结果(1)GluR2免疫反应阳性神经元大部分出现在视皮层Ⅱ-Ⅲ层和Ⅴ-Ⅵ层内,并且GluR2主要在锥体神经元的胞体和树突表面表达,Ⅳ层内少量非锥体神经元表面有微弱的GluR2标记;(2)视皮层Ⅱ-Ⅲ层和Ⅴ-Ⅵ层内,GluR2阳性神经元数量随发育逐渐增加,生后5周时达顶峰,随后保持稳定的水平;(3)视皮质Ⅱ-Ⅲ层和Ⅴ-Ⅵ层内,GluR2免疫反应的平均光密度值随发育逐渐增加,生后6周时达顶峰,随后保持稳定的水平。结论可塑性关键期高峰到终止阶段,大鼠视皮层II-III层和V-VI层内GluR2表达逐渐增加,关键期终止时达顶峰;包含GluR2亚基的AMPA受体可能通过稳定突触结构参与视觉可塑性关键期的终止。Objective To investigate mechanisms terminating the critical period of visual plasticity, developmental expression of amino-3-Hydroxy- 5methylisoxazole-4-propionicacid receptor （AMPA-recoptor） subunit GhtR2 in rat visual cortex was studied around the termination of cirtical period of plasticity. Methods The AMPA receptor subunit GluR2 was labeled by immunofluorescence in rat visual cortex from postnatal third week（3rd week） to postnatal eighth week（8th week）,Results （ 1 ） Most of GhtR2 immunopositive neurons were present in cortical layers Ⅱ-Ⅲ and Ⅴ-Ⅵ,GluR2 predominantly expressed in the somata and dendrites of pyramidal neurons. Only a very faint signal was detected in non-pyramidal neurons in layer Ⅳ. （2） Numbers of GluR2 immunopositive neurons in cortical layers Ⅱ-Ⅲ and Ⅴ-Ⅵ were up-regulated,and to the peak at fifth week, then keep stablization. （ 3 ） The average optical density of GluR2 immunoreactivity in cortical layers Ⅱ- Ⅲ and Ⅴ- Ⅵ was up-regulated from 3rd week to 6th week, and without significant changes from 6th week to 8th week. Sixth week was its peak. Conclusion From the peak of critical period of visual plasticity to termination, the expression of GluR2 in cortical layers Ⅱ - Ⅲ and Ⅴ- Ⅵ was up-regulated, and achievced peak level at termination of critical period. The AMPA receptor containing GluR2 involved in terminating critical period of visual plasticity.

关 键 词：视皮层 免疫荧光 发育 AMPA受体 

分 类 号：Q959.836[生物学—动物学] R777.4[医药卫生—眼科]