摘要
目的观察在脉冲时间依赖的刺激诱导模式下单眼形觉剥夺对小鼠视觉发育关键期内初级视皮层V1B区长时程增强（timing long-term potentiation,t LTP）的影响及其对应诱导时间窗的变化。方法选择健康C57BL/6小鼠28只,随机分为正常对照组和单眼形觉剥夺组,每组14只,单眼形觉剥夺组右眼褥式缝合3 d。七氟烷麻醉后,断头、取脑,置于含体积分数95%O2和5%CO2饱和的0~4℃脑片制备液中冷却1~2 min,切取后部2/5脑组织,行400μm冠状连续切片,在脉冲时间依赖的条件刺激诱导模式下采用红外可视膜片钳全细胞模式记录正常对照组、单眼形觉剥夺组（含剥夺侧皮层、非剥夺侧皮层）视皮层V1B区脑片Ⅱ/Ⅲ层锥体神经元NMDA介导的兴奋性突触后电位（excitatory postsynaptic potentials,EPSP）。结果正常对照组小鼠脑片初级视皮层V1B区Ⅱ/Ⅲ层锥体神经元予间隔Δt=10 ms的突触前后联合刺激后EPSP反应增加,可成功诱导t LTP,但当Δt=100 ms则未能诱导t LTP[Δt=＋10 ms：EPSP斜率（124.1±3.9）%;Δt=＋100 ms：EPSP斜率（100.4±3.3）%;P〈0.001）。单眼形觉剥夺组小鼠剥夺侧初级视皮层分别给予Δt=10 ms、100 ms的脉冲时间依赖的条件刺激均可诱导出t LTP[Δt=＋10 ms：EPSP斜率（130.8±1.7）%;Δt=＋100 ms：EPSP斜率（114.7±0.3）%;P〈0.001）。单眼形觉剥夺组小鼠非剥夺侧视皮层分别给予Δt=10 ms、50 ms的脉冲时间依赖的条件刺激均可诱导出t LTP[Δt=＋10 ms：EPSP斜率（129.6±1.5）%;Δt=＋50 ms：EPSP斜率（120.5±0.9）%],而当Δt=100 ms时,未能成功诱导t LTP[Δt=＋100 ms：EPSP斜率（101.1±0.6）%]。结论单眼形觉剥夺3 d可以改变小鼠初级视皮层V1B区兴奋性通路的脉冲时间依赖的突触可塑性。剥夺侧较非剥夺侧及正常视皮层t LTP诱导时间窗增宽,有助于从突触可塑性角度解释弱视内在神经突触机制。
Objective To investigate the effects of monocular form deprivation on timing long-term potentiation（tLTP） in the V1 B area of mouse primary visual cortex in the critical period of mice visual development under the spike-timing dependent induction pattern,and observe the timing window change of tLTP.Methods Twenty-eight healthy C57BL/6 mice were randomly divided into normal control group and monocular form deprivation group,14 cases in each group,the right eye of mice in monocular form deprivation group was sutured for 3 days.After anesthetizing by sevoflurane,the brains were quickly removed to ice-cold buffer bubbled with 95%O_2 and 5%CO_2 for 1-2 minutes.Rear 2/5 brain tissue including the visual cortex were cut into 400 μm brain slices.Visualized whole-cell current-clamp recordings were made from layer Ⅱ/Ⅲ regular-spiking pyramidal cells（deprived side or nondeprived side） to record the excitatory postsynaptic potentials（EPSP）.Results In normal control group,the pre-then post-pairing stimulation in layer Ⅱ/Ⅲ regular-spiking pyramidal cells resulted in tLTP when the delay（At） was 10 ms（EPSP slope 124.1%± 3.9%）,but not when △t was 100 ms（EPSP slope 100.4%±3.3%）（P〈0.001）.In the deprived side of from monocular deprivation group,both delays（10 ms,100 ms） resulted in comparable tLTP（△t=＋10 ms：EPSP slope 130.8%±1.7%;△t=＋100 ms：EPSP slope 114.7%±0.3%;P〈0.001）.In non-deprived visual cortex,the pre-then post-pairing stimulation resulted in tLTP when the delay was 10 ms and 50 ms（△t = ＋10 ms：EPSP slope 129.6%±1.5%;△t= ＋50 ms：EPSP slope 120.5%±0.9%）,but not when it was- 100 ms（△t = ＋100 ms：EPSP slope 101.1%±0.6%）.Conclusion Monocular form deprivation for 3 days can change the spike-timing dependent synaptic plasticity of excitory pathway in the V1 B area of mouse primary visual cortex.The timing window for postsynaptic tLTP of deprived visual cortex is wider than those of non-deprived and normal visual cortex,which may help to ex
出处
《眼科新进展》
CAS
北大核心
2016年第6期512-515,519,共5页
Recent Advances in Ophthalmology
基金
国家自然科学基金资助(编号:30730099)
天津市应用基础与前沿技术研究计划青年项目(编号:14JCQNJC10500)~~
关键词
单眼形觉剥夺
脉冲时间依赖突触可塑性
长时程增强
monocular form deprivation
spike-timing dependent synaptic plasticity
timing long-term potentiation
