大鼠视觉发育可塑性关键期终止前后视皮层AMPA受体电流的发育变化  

Changes of AMPA receptor-mediated excitatory postsynaptic currents in rat visual cortex around critical period of plasticity

作　　者：王昌鹏[1] 阴正勤[1] 秦伟[1] 翁传煌[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9期641-645,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。对可塑性关键期终止前后，正常大鼠视皮层α-氨基-3-羟基-5-甲基4-异恶唑丙酸（amino-3-hydroxy-5-methylisoxazole-4-propionicacid，AMPA）受体介导的兴奋性突触后电流进行了研究。方法采用脑片膜片钳全细胞记录技术，记录生后3～8周正常大鼠视皮层AMPA受体介导的兴奋性突触后电流。结果在大鼠视皮层Ⅱ—Ⅳ层，95倒神经元形成全细胞记录，其中记录到AMPA受体电流43例；生后3～8周，视皮层神经元的输入阻抗、静息膜电位差异无统计学意义；生后3—8周，AMPA受体电流的潜伏期、上升时间、下降时间及半波宽差异无统计学意义；生后3～6周AMPA受体电流的幅值随发育逐渐增加，6～8周幅值变化不显著。结论视觉发育可塑性关键期高峰到成年阶段，大鼠视皮层神经元被动膜学特性无明显变化；AM—PA受体电流幅值随发育逐渐增加，关键期终止时达顶峰；突触后AMPA受体的功能变化可能参与了视觉发育可塑性关键期的终止过程。Objective To investigate mechanisms ending the critical period of visual plasticity, the amino-3-hydroxy-5-methylisoxazole-4-propionicacid （AMPA） receptor-mediated excitatory postsynaptic currents （AMPA-EPSCs） in rat visual cortex was studied around the end of cirtical period of plasticity. Methods From postnatal third week （3rd week） to postnatal eighth week （ 8th week） ,AMPA-EPSCs in rat visual cortex was recorded by whole-cell patchclamp technique. Results Whole-cell recording in 95 neurons was obtained in layers Ⅱ-Ⅳ of rat visual cortex, in which AMPA-EPSCs was recorded in 43 neurons;From the 3rd week to the 8th week,the input resistance（IR） and resting membrane potential（RblP） of 95 neurons in visual cortex showed no significant changes;From the 3rd week to the 8th week, the latency, rise time, decay time and half width of AMPA-EPSCs showed no significant changes;The amplitude of AMPA-EPSCs gradually increased from the 3rd week to the 6th week and showed no significant changes from the 6th week to the 8th week. Conclusion From the peak of critical period of visual plasticity to adulthood, membrane properties of neurons in rat visual cortex showed no significant changes. The amplitude of AMPA-EPSCs gradually increased with age and achieved maximum level at the end of critical period. Functional changes of postsynaptic AM- PA receptor involved in the end of critical period of visual plasticity.

关 键 词：视皮层 兴奋性突触后电流 全细胞记录 AMPA受体 大鼠 

分 类 号：R774[医药卫生—眼科] Q959.836[医药卫生—临床医学]