GluR2在大鼠蜗核的年龄依赖性表达及与突触发育的关系

GluR2 expression in developing rat cochlear nucleus and relationship with development of synapse

目的检测α-氨基-3-羟基-5-甲基-4-异恶唑丙酸(AMPA)受体亚型GluR2和突触小泡蛋白(SYP)在不同年龄大鼠蜗核中的表达,探讨GluR2的表达规律及与突触发育的关系。方法选取2、3、4、6、8和10周SD大鼠,应用免疫荧光组化方法观察各年龄大鼠GluR2及SYP在蜗核中的表达及其相互关系。结果GluR2在不同年龄大鼠蜗核神经元中均有表达,生后2、3周时表达较弱,4周时逐渐增强,6周达高峰,之后急剧下降,10周表达最弱。GluR2在大鼠耳蜗背侧核颗粒细胞层表达较强,在分子层和多极细胞层表达较弱。SYP在不同年龄大鼠蜗核神经元中均有表达,生后2周表达最弱,4周显著增强,6周为高峰,8周时骤然降低并稳定表达。结论大鼠生后发育过程中蜗核GluR2及SYP的表达呈现基本一致的年龄依赖性规律,GluR2在蜗核的表达可能与蜗核突触成熟及功能发育有关,其年龄依赖性表达现象可能是中枢神经系统感觉功能发育及可塑性的重要机制。

Objective To investigate the trend of developmental expression of GluR2, subtype of alpha-amino-3-hydroxy-5-methylisoxazole4-propionic acid（AMPA） receptor and synaptophysin （SYP） in the rat cochlear nucleus（CN） in different developmental stages, and explore the association of GluR2 expression with the development of synapse. Methods SD rats of 2, 3, 4, 6, 8 and 10 weeks old were selected,the expression of GluR2 and SYP in CN was detected with immunofluorescence histochemical method, and the association of them was explored. Results GluR2 expression was observed in all the neurons of CN in each postnatal groups. The expression was relatively weaker in the second and third week, became denser in the fourth week, reached the peak in the sixth week and then sharply decreased to the weakest in the tenth week. The expression of GluR2 was denser at granular cell layer, while weaker at molecular layer and multipolar cell layer in the dorsal CN. SYP expression was detected in all the neurons of CN in each postnatal groups. The expression was weakest in the second week, significantly denser in the fourth week, reached the peak in the sixth week, was then sharply decreased and stably maintained. Conclusion The expressions of GluR2 and SYP in the postnatal rat CN exhit an equally age-dependent tendency. The expression of GluR2 in the CN may be associated with the the maturation and function development of the CN. The different expression and distribution of GluR2 and SYP in the rat CN of different developmental stages may be involved in the development and plasticity of auditory center.