【摘要】 用标准微电极技术记录大鼠心室肌经低温处理1～3d后某些电学性质的变化。低温处理后的标本,复温到36±1℃后,动作电位幅度无明显改变,但动作电位时程(APD₉₀)显著延长。快速驱动（10～30Hz）可使低温处理标本产生迟后去极化（DAD）和触发活动（TA）。并且驱动频率越高,持续时间越长,所引起的DAD幅度越大,越易发生TA。无K⁺灌流、哇巴因1～4×10^-5mol/L以及咖啡碱7.1～14.2×10³mol/L处理可使低温处理标本产生DAD和TA。结果表明,大鼠心室肌细胞能耐受较长时间的低温处理。但经处理后,心室肌的某些电学性质发生改变,它们对能引起细胞内Na⁺或Ca²⁺增加的因素更为敏感,更易产生DAD及TA。更多还原

【Abstract】 Conventional microelectrode technique was used to investigate the electric changes of rat ventricular fibers after low temperature treatment (LTT) for 1-3 d.When the LTT preparations were rewarmed to 36±1℃ in Tyrode’s solution, the amplitudes of action potentials had no significant changes, but the duration of action potentials (APD90) became much longer. Delayed after-depolarization (DAD) and triggered activities . could be induced by stimulations (10-30 Hz) on LTT preparations. Besides, the higher the frequency and the longer the stimulation, the higher the amplitude of DAD. K+-free su-perfusion, ouabain 1-4×10-5 mol/L and caffeine 7.1-14.2 mmol/L treatments also could induce DAD and triggered activities in LTT preparations.The results revealed that the ventricular fibers of rat hearts could tolerate long time of LTT. But after LTT, the ventricular fibers showed changes in electrical properties. They had longer APD90 and were more sensitive to those factors which could increase intracellular [Na+] and [Ca2+]; therefore DAD and triggered activities were easier to be induced.更多还原