快速老化小鼠海马神经元电压门控离子通道特点

目的：观察快速老化小鼠（Senescence-accelerated mouse,SAM)海马神经元的基本离子通道特点，并对抗快速老化亚系（SAM－resistance/1,SAMR1)与快速老化亚系（SAM－prone/8,SMAP8)的基本离子通道特点进行了比较，探讨了离子通道变化在衰老中的可能角度，方法：应用全细胞记录方式，观察并比较原代培养SAMR1和SAMP8海马神经元的电压门控离子通道及膜参数。结果：原代培养SAMR1和SAMP8海马神经元电压门控Na^2 通道电流（INa)和电压门控延迟整流K^ 通道电流（IK）的电学特点和幅度基本一致。SAMP8的电压门控Ca^2 通道电流（ICa)和瞬时外向K^ 通道电流（IA）的幅值则大于相同培养天数的SAMR1。经膜电容校正所得的ICa电流密度也表现出增大的变化规律。结论：SAMP8与SAMR1神经元间IA和ICa的差异可能与其神经系统变异而产生的学习记忆功能下降有关。

The characteristics of voltage-dependent channels of cultured hippocampal neurons in senescence-accelerated mouse

Objective: To investigate the changes of voltage dependent ion channels of cultured hippocampal neurons in SAM and compare sodium, potassium and calcium channel currents and membrane capacitance (Cm) and resistance (Rm) between SAMR1 and SAMP8. Method: By utilizing whole cell mode patch clamp technique. Results: The features and amplitude of voltage dependent Na + current (I Na ) and out delayed rectifier K + current (I k ) of hippocampal neurons are similar between two strains. However, the voltage dependent Ca 2+ current (I Ca ), as well as current density corrected for membrane capacitance, and transient K + current (I A ) of SAMP8 neurons are larger than those of SAMR1 at neurons at the same DIC. No change of Cm and Rm was found between the two strains. Conclusion: The differentiation of I Ca and I A may be involved in malfunction of the hippocampus in SAMP8.