活性氧对豚鼠心室肌细胞不同钾通道离子电流的影响

目的：揭示年头自由基导致跨膜电位变化的离子电流基础。方法：采用全细胞膜片钳技术，观察了Ｈ２Ｏ２（１ｍｍｏｌ／Ｌ）对豚鼠单个心室肌细胞不同钾通道影响。结果：Ｈ２Ｏ２使习心肌细胞静息电位（ＲＰ）降低，动作电位时程（ＡＰＤ）显著缩短的同时，明显抑制超极化时的内向整流钾电流（Ｉｋ１），致（Ｉｋ１）正常呈Ｎ字型Ｉ－Ｖ曲 成一条斜线；增强延迟整流钾电流（ＩＫ）的快组分（ＩＫＲ）和慢组分（ＩＫＡ），尤其ＩＫＲ２

Effect of H2O2 on different potassium channel ionic currents of ventricular myocytes of guinea pig

AIM: To reveal ionic curret basis of the change of transmembrane potential induced by oxygen free radical.METHOD:The wholfe cell mecording pach clamp techique was used to investigate the effect of H2O2(1 mmol/ L) on differen potassium channel ionic currents of ventricular myocytes of guinea pig. RESULTS : It was found that H2O2 reduced rest potential (RP) and shortened action potential duration (MPD) significantly , inhibited the inward rectifier K current(IK1)markedly ,H2O2 changed the current - voltage (I- V) relation to IK1 from a N shape to a /shape and enhaned the rapid component (IKr) and the slow compoent (IKs) of the delayed outward retifier K current (Ik), especially Ikr, and made IK I - V curve shift to up - right. CONCLUSION: Different effects of oxygen free radical on IK1 and IK of ventricular myocytes is a possible ionic mechanism for the chang of transmembrane potential and arrhythmia indued by oxygen free redical.