中文摘要：

大脑快速发育期（brain growth spurt，BGS）是神经元生长、突触连接的关键时期；电压门控性K＋通道是维持细胞兴奋性和神经元间信息传递的关键通道。本文旨在探究BGS期内大鼠海马CAl区锥体神经元电压门控性K＋通道电流及其通道动力学特性的变化，以期找出大鼠海马CAl区锥体神经元电压门控性K＋通道发育的关键期。采用全细胞膜片钳技术，研究出生后0-4周大鼠海马CAl区脑片上的锥体神经元全细胞电压门控性K＋通道电流及其通道动力学特性。结果显示：在测试电压为＋90mV下，以出生后0周为参照，出生后1-4周的瞬时外向K＋通道电流（，A）的最大电流密度的增幅分别为（16．14±0．51）％、（81．73±10．71）%、（106．72±5．29）％、（134．58±8．81）％（n=10，P〈0．05）；延迟整流K＋通道电流（，K）的最大电流密度增幅分别为（16．75±3．88）％、（134．01±2．85）％、（180．56±8．49）％、（194．5±8．53）％（n=10，P〈0．05），显示K＋通道电流密度于1～2周增幅最大；IA的激活曲线向左移，半数激活电压随周龄增加逐渐减小，分别为14．67±0．75、13．46±0．64、8．39±0．87、4．60±0．96、0．54±0．92（mV,n=10，P〈0．05）；Ik的激活曲线向左移，半数激活电压随周龄增加逐渐减小，分别为8．94±0．85、6．65±0．89、0．47±1．15、-1．80±0．89、-8．56±1．08（mVn=10，P〈0．05）。IA的失活曲线向左移，ON龄与1周龄之间的半数失活电压没有显著性差异，而出生后1～4周随周龄增加半数失活电压逐渐减小（P〈0．05），分别为-45．68±1．26、-46．81±0．78、-48．64±0．81、-51．96±1．02、-58．31±1．35（mVn=10）。以上结果表明，随着鼠龄的增加，IA和Ik电流密度逐渐增加，电压门控性K＋通道半数激活、失活电压降低，尤其是出生后1周至2周变化明显，上述变化与海马神

英文摘要：

Brain growth spurt （BGS） is the critical period of neuronal growth and synaptic connection. The voltage-gated K＋ channel is the key channel for maintenance of cell excitability and information transfer among neurons. The purpose of the present study is to investigate the critical period of voltage-gated K＋ channel development in hippocampal CA1 neurons during the BGS. Changes of voltage-gated K＋ currents in neurons from acutely isolated hippocampal CA1 brain slices of rats at different ages （0-4 weeks after birth） were recorded by the whole-cell patch-clamp technique. The depolarization voltage was set at ＋90 mV, and 0 week was set as the control group. The experimental results showed that, with increasing ages （1-4 weeks）, the maximum current densities OflA in- creased by （16.14 ±0.51）%, （81.73 ± 10.71）%, （106.72± 5.29）%, （134.58 ± 8.81）% （n = 10, P 〈 0.05）, and the maximum current densities oflK increased by （16.75 ± 3.88）%, （134.01 ±2.85）%, （180.56 ± 8.49）%, （194.5± 8.53）% （n = 10, P 〈 0.05）, respectively, compared with those in 0 week. During 0-4 weeks after birth, the activation kinetics of IA shifted to left, and the half activation voltages OflA were 14.67 ± 0.75, 13.46 ± 0.64, 8.39 ± 0.87, 4.60 ± 0.96, 0.54± 0.92 （mV, n = 10, P 〈 0.05）, respectively; The activation kinetics oflK shifted to left and the half activation voltages oflK were 8.94 ± 0.85, 6.65 ± 0.89, 0.47 ± 1.15, -1.80 ± 0.89, -8.56 ± 1.08 （mV, n = 10, P 〈 0.05） respectively. The inactivation kinetics oflA also shifted to left, and the half inactivation voltages were -45.68 ± 1.26, -46.81±0.78, -48.64 ± 0.81, -51.96 ± 1.02, -58.31 ± 1.35 （mV, n = 10） respectively at 0, 1, 2, 3 and 4 weeks after birth, which showed no significant changes between 0 and 1 week, but significant decreases during 1-4 weeks after birth （P 〈 0.05）. These results indicate that the current densities of 1A and 1 increase and the kinetic characteristics of the volt