外周听觉改变致听皮质突触N-甲基D-天冬氨酸受体亚基表达变化

目的观察听觉剥夺后重塑模型中听皮质突触N-甲基D-天冬氨酸受体亚基(N-methyl-D-aspartate receptor subunit 2B,NR2B)表达变化。方法采用清洁级SD大鼠90只,分成听觉剥夺组、听觉剥夺后重塑组及对照组,Optiprep沉降梯度超速离心从初级听皮质提取高度纯化的突触体后,采用Western blotting蛋白质印迹检测技术对生后听觉剥夺14天组、28天组、42天组、听觉剥夺7天后再给予纯声暴露的各实验组听皮质突触体NR2B表达进行比较。结果听觉剥夺使生后14天组和28天组动物听皮层NR2B表达水平明显下降(P<0.05),听觉剥夺7天后再给予纯声暴露则又使NR2B表达水平明显提高(P<0.05),呈现双向调节趋势。听觉剥夺和纯声暴露对生后42天组成熟大鼠听皮层NR2B表达不再产生明显调节作用(P>0.05)。结论在大鼠生后发育关键期,听觉剥夺、可改变听皮层NMDA受体NR2B蛋白表达水平;为研究感觉功能发育可塑性机制提供了重要实验资料。

Auditory deprivation and expression of NR2B in auditory cortex of rat

OBJECTIVE To study the changes of N-methyI-D-aspartate receptor subunit 2B (NR2B) expression at local synapses in auditory cortices after early postnatal auditory deprivation and tone exposure. METHODS Highly purified synaptosomes from primary auditory cortex by Optiprep floatation gradient centrifugations were prepared.The differences of NR2B expression were compared in auditory deprivation PNDI4,PND28,PND42 and tone exposure after auditory deprivation for 7 days by Western blotting. RESULTS NR2B protein expression of PNDI4 and PND28 decreased significantly (P<0.05) when auditory deprivation for 7days.Tone exposure after auditory deprivation for 7 days made NR2B protein level increased significantly (P<0.05).It showed bidirectional regulation of NR2B protein.No significant effects of auditory deprivation and lone exposure on the relative expression level of NR2B of PND42 (P>0.05) were found.CONCLUSION The results indicate that auditory deprivation can modify the protein expression level of NR2B during the critical period of postnatal development in rat.These findings provide important data to the study of the mechanisms for the developmental plasticity of sensory functions.