小鼠视觉发育前关键期视皮层神经元反应特性与突触可塑性  

Response properties of neurons and synaptic plasticity during pre-critical period of visual development inmouse visual cortex

作　　者：史学锋[1] 赵堪兴[1] 

机构地区：[1]天津市眼科医院天津市眼科学与视觉科学重点实验室天津市眼科研究所天津医科大学眼科临床学院,300020

出　　处：《中华实验眼科杂志》2016年第4期298-304,共7页Chinese Journal Of Experimental Ophthalmology

基　　金：国家自然科学基金重点项目（30730099）;国家自然科学基金面上项目（81371049）;天津市自然科学基金项目（11JCYBJC12700）

摘　　要：背景人类及哺乳动物的视觉发育主要是在生后关键期内完成的，但此期并非是哺乳动物接受视觉经验刺激的最早期。小鼠等哺乳动物视觉发育的关键期前还存在前关键期。目前，前关键期视皮层神经元的反应特性及突触可塑性研究仍处于探索阶段。目的探讨小鼠前关键期视皮层神经元的反应特性及突触可塑性特点。方法选择生后13～17d的C57BL／6J小鼠48只，分别采用在体膜片钳全细胞记录及离体脑片膜片钳全细胞记录法记录小鼠视皮层第Ⅳ层神经元的电生理反应。在体记录在小鼠麻醉下进行，在电流钳模式下给予步阶电流刺激，测量其在体膜反应特性。给予最优刺激参数的移动光棒刺激，测量其视觉诱发反应特性。完成在体实验后行离体实验，分别测量神经元离体膜反应特性及白质-第Ⅳ层通路刺激条件下的诱发反应特性。采用随机数字表法将实验动物随机分成4个组，各组雌雄比例分配均匀。每组测定12个细胞，按照刺激频率的不同分别行低频刺激（LFS）和高频刺激[0波脉冲刺激（TBS）]模式训练，按照刺激时序的不同进行突触前一后（pre-post）模式和突触后-前（post—pre）模式训练，在-70mV电压钳制下分别记录训练前后兴奋性突触后电流（EPSCs）。采用pClmap10软件对原始数据进行预处理，采用Matlab2008a软件进行统计分析。结果在体成功记录的细胞数为39个，离体记录48个。在体和离体条件下视皮层第Ⅳ层神经元稳态平均发放动作电位（AP）个数分别为1．01±0．03和1．01±0．05，AP阈值分别为（-40．2±3．2）mV和（-39．6＋2．0）mV，阈电流水平分别为（126．7±17．4）pA和（129．6±17．5）pA，差异均无统计学意义（AP数：t=0．512，P=0．610；AP阈值：t=-1．074，P=0．286；阈电流：t=-0．776，P=0．440）。在体最优视觉刺激条件下平均膜电位峰值幅度为（7Background The visual development is completed during the critical period in human andmammals. However,the critical period is not the initial of receiving visual experience. It is known that before the onset of critical period in mammals,such as mouse,there is an earlier stage for visual development,the pre-critical period. The research of response characteristics of the visual cortical neurons and the syuaptic plasticity in the pre-critical period is still in the exploratory stage. Objective The study aimed to preliminarily investigate the response properties of neurons and synaptic plasticity in mouse visual cortex during the pre-critical period. Methods Forty- eight postnatal day 13-17 C57BL/6J mice were used for in vivo whole-cell recordings and in vitro brain slice whole- cell recordings. In vivo whole-cell recordings were done in anesthetized mice. Moving bars in different directions were produced and controlled by a Matlab program. Cell recordings were obtained at the depth of layer IV of visual cortex. Step current stimuli under current clamp were given to measure the membrane response properties of neurons. Optimal visual stimuli were given to measure the in vivo largest responses of membrane potentials. In vitro experiments were performed after in vivo experiments. All cells were given current step stimuli to measure the membrane response properties of neurons. Different intensities of white-matter-to- layer-ivpathway stimulation were given to measure the evoked response properties. All cells from 48 mice were randomized into 4 groups according to different stimulus training modes, including low frequency stimulation （ LFS）, high frequency theta-burst stimulation （ TBS）, pre-post synaptic timing stimulation （pre-post TS） and post-pre synaptic timing stimulation （post-pre TS）. Under the voltage clamp of -70 mV,excitatory postsynaptic currents （EPSCs） before and after training were recorded to measure the plastic changes of excitatory synaptic connections, pClamp 10 was used for the pr

关 键 词：视皮层/生长和发育 神经可塑性/生理 突触传递/生理 动作电位 兴奋性突触后电位 近交系C57BL小鼠 膜片钳技术 

分 类 号：R77[医药卫生—眼科]