年龄和视觉经验对大鼠视皮层突触功能发育的影响  

Effects of age and visual experience on the synaptic function development in rat visual cortex

作　　者：高朋芬[1] 阴正勤[1] 刘应兵[2] 王仕军[1] 胡志安[1] 

机构地区：[1]第三军医大学附属西南医院眼科,重庆400038 [2]四川大学基础医学院生理学教研室,成都630041

出　　处：《第三军医大学学报》2003年第21期1920-1923,共4页Journal of Third Military Medical University

基　　金：国家自然科学基金资助项目(39970252;30025014;30070254)~~

摘　　要：目的研究大鼠视觉发育可塑性关键期视皮层Ⅱ-Ⅲ层神经元的电学特性变化及其与大鼠生理年龄及视觉经验的关系,探索视皮层经验依赖性可塑性的突触和细胞机制.方法制备0～25 d龄大鼠视皮层脑片,利用膜片钳全细胞记录法记录Ⅱ-Ⅲ层神经元的突触后电流(Post synaptic currents, PSCs).结果①随着大鼠天龄增大,无反应型PSCs迅速减少,P0～5d组、P6～10d组与P11～25d组之间相差非常显著(P<0.01),而各组内无显著差异.多突触型PSCs随天龄增大逐渐增多.②细胞的静息电位、输入阻抗、PSCs峰值、10%～90%上升及下降时间、半波宽随大鼠天龄增大呈规律性变化,各组差异主要体现在P0～5d组与其它组之间(P<0.05),而P11～14d组与P15～25d组间差异不显著(P>0.05).结论①视皮层细胞的静息电位、输入阻抗、PSCs反映不同发育阶段视皮层突触功能特性.②视皮层突触的形成是一个程序化过程,年龄和视觉经验共同参与突触成熟,但在正常大鼠视觉发育可塑性关键期内,年龄可能是决定性因素,而睁眼后形觉刺激参与突触修饰、稳定和固化.Objective To study the electrophysiological properties of postsynaptic neurons from layer Ⅱ-Ⅲ in normal rat visual cortex during the critical period of visual plasticity and its relationship with age and visual experiences and to explore the synaptic and cellular mechanisms of experience-dependent plasticity in visual cortex. Methods Postsynaptic currents (PSCs) of layer Ⅱ-Ⅲ in visual cortex slices of Wistar rats aged P0-25d were recorded by whole cell patch clamp recording method. Results(1) The percentage of irresponsive PSCs in rat visual cortex decreased rapidly in an age-dependent manner. There was significant difference between P0-5d group, P6-10d group and P11-25d group( P < 0.01) , but no difference in the same group. The percentage of polysynaptic PSCs increased in an age-dependent manner. (2) The resting membrane potentials (RMP) and the input resistance (IR) of the neurons, the peak amplitude, 10% ~ 90% rise time, 10% -90% decay time and half-width of PSCs changed regularly in an age-dependent manner. There was significant difference between P0-5d group and other groups, but no significant difference was found between P11-14d group and P15-25d group( P >0.05) . Conclusion The electrophysiological properties of visual cortical synapses at different stages during development can be reflected by PSCs, RMP and IR. The synaptic formation in rat visual cortex is a programmed process. Age may be the crucial factor while visual experience is an outer factor for the regulation of the development of synapses during the critical period of visual plasticity, while the patterned visual stimuli might participate in the modification, stabilization and solidification of the visual cortical synapses.

关 键 词：视皮层 发育 突触 全细胞记录 大鼠 

分 类 号：R338.3[医药卫生—人体生理学] R339.3[医药卫生—基础医学]