摘要目的:探讨C57BL/6J野生型小鼠在不同发育阶段大脑初级视皮质双眼区（primary visual cortex binocular zone，V1B区）Ⅳ层锥体神经元的微小突触后电流发育性变化。方法:实验研究。选择出生后第14天（睁眼前后）、28天（关键期高峰段）、35天（关键期结束）和130天（完全成年期）的无特定病原体级健康雄性C57BL/6J小鼠16只，按日龄分为4个组，分别为P14组、P28组、P35组和P130组。采用全细胞膜片钳技术，记录各组小鼠大脑V1B区Ⅳ层锥体神经元微小兴奋性突触后电流（mEPSC）和微小抑制性突触后电流（mIPSC）的频率和振幅，分析其差异和变化。结果:小鼠大脑V1B区Ⅳ层锥体神经元的mEPSC频率4个组间比较，差异有统计学意义（ F=9.46， P<0.001），其中P35组高于P28组［P28和P35组分别为（8.72±1.34）和（13.28±4.05）Hz， t=3.39， P=0.012］，P130组低于P35组［P35和P130组分别为（13.28±4.05）和（5.82±1.98）Hz， t=5.21， P<0.001］；mEPSC振幅4个组间比较，差异无统计学意义（ F=2.84， P=0.055）。小鼠大脑V1B区Ⅳ层锥体神经元的mIPSC频率4个组间比较，差异有统计学意义（ F=8.14， P<0.001），其中P130组高于 P14组［P14组和P130组分别为（5.22±1.33）和（12.03±3.94）Hz， t=4.678， P<0.001］；锥体神经元mIPSC振幅4个组间比较，差异有统计学意义（ F=7.06， P=0.001），其中P35组高于P28组［P28组和P35组分别为（20.07±3.56）和（28.47±5.98）pA， t=3.66， P=0.006］，P130组低于P35组［P35组和P130组分别为（28.47±5.98）和（20.32±3.55）pA， t=3.33， P=0.014］。 结论:小鼠大脑V1B区锥体神经元兴奋性突触发育在发育期呈旺盛增长状态，随着日龄增加而逐渐减弱，抑制性突触发育随着小鼠日龄增加逐渐增强，且两者均在关键期迅速发育。

abstractsObjective:To investigate the developmental changes of miniature excitatory and inhibitory postsynaptic currents (mEPSCs and mIPSCs) of layer Ⅳ pyramidal neurons in the primary visual cortex binocular zone (V1B) of C57BL/6J wild-type mice at different developmental stages.Methods:Sixteen male C57BL/6J mice of specific-pathogen-free grade were selected and divided into 4 groups according to their postnatal age: P14 group (before and after eye opening), P28 group (the peak of the critical period), P35 group (the end of the critical period), and P130 group (fully adult). Whole-cell patch-clamp technique was used to record the frequency and amplitude of mEPSCs and mIPSCs of layer Ⅳ pyramidal neurons in V1B of each group, and to analyze their differences and changes.Results:The frequency of mEPSCs of layer Ⅳ pyramidal neurons in V1B of mice in the four groups was statistically different ( F=9.46, P<0.001), with the P35 group being higher than the P28 group [P28 and P35 groups were (8.72±1.34) and (13.28±4.05) Hz, t=3.39, P=0.012], and the P130 group being lower than the P35 group [P35 and P130 groups were (13.28±4.05) and (5.82±1.98) Hz, t=5.21, P<0.001]; the amplitude of mEPSCs of layer Ⅳ pyramidal neurons in V1B of mice in the four groups was not statistically different ( F=2.84, P=0.055). The frequency of mIPSCs of layer Ⅳ pyramidal neurons in V1B of mice in the four groups was statistically different ( F=8.14, P<0.001), with the P130 group being higher than the P14 group [P14 and P130 groups were (5.22±1.33) and (12.03±3.94) Hz, t=4.678, P<0.001]; the amplitude of mIPSCs of layer Ⅳ pyramidal neurons in V1B of mice in the four groups was statistically different ( F=7.06, P=0.001), with the P35 group being higher than the P28 group [P28 and P35 groups were (20.07±3.56) and (28.47±5.98) pA, t=3.66, P=0.006], and the P130 group being lower than the P35 group [P35 and P130 groups were (28.47±5.98) and (20.32±3.55) pA, t=3.33, P=0.014]. Conclusions:The excitatory synaptic development of layer Ⅳ pyramidal neurons in V1B of mice is in a vigorous growth state during development and gradually weakens with age, while the inhibitory synaptic development gradually strengthens with increasing postnatal age, and both of them rapidly develop during the critical period.