摘要
目的 探讨L型钙通道在急性心肌梗死 (AMI)后室性心律失常发生的作用及机制。 方法 开胸冠脉结扎制备兔AMI模型 ,于 1周和 2个月处死动物分离心室肌细胞 ,以膜片钳技术记录梗死及周边区心外膜细胞L型钙通道电流(ICa L)的变化。 结果 AMI兔梗死周边区心外膜细胞ICa L受到抑制 ,I V曲线上移 ,其峰值电流密度在正常对照组、梗死后 1周和 2个月分别为 (-5 5 8± 1 5 3 ) pA /pF、(-3 5 2± 0 93 ) pA/pF (n =6,与对照组比较P <0 0 5 )和 (-4 84± 1 48)pA/pF(n =11,与对照组比较P <0 0 5 ) ,但I V曲线的形态轨迹不变。其失活曲线左移 ,失活速度加快 ,半数最大失活电位分别为 (-13 1± 4 2 )mV、(-2 5 9± 7 0 )mV和 (-2 1 3± 5 6)mV ,P <0 0 5。 结论 AMI后梗死周边带心外膜细胞ICa L通道受抑制 ,可能为AMI后发生室性心律失常的机制之一 ;梗死后 2个月钙通道异常程度减轻 。
Objective To explore roles and machinism of L type calcium currents in pathogenesis of ventricular arrythmia after acute myocardial infarction(AMI). Methods Rabbit AMI models were made by ligation of branches of left coronary artery.After 1 week and 2 months, single pericardial myocytes were isolated enzymatically from ischemic zone adjacent to infarcted area and normal control myocytes from similar regions in normal rabbit hearts were collected in the same way.I Ca L was recorded with patch clamp techniques in the whole cell configuration. Results ICa L was inhibited in the pericardial myocytes from the ischemic area adjacent to the infarcted zone;I V curve was elevated.Peak of I Ca L density of ischemic cells was significantly reduced in AMI after 1W (-3.52±0.93 pA/pF, n =6);compared with that in control cells (-5.58±1 53pA/pF, n =10) there was a significant differenc, P <0 05.However,the peak of I Ca L density in AMI after 2M (-4.84±1 48 pA/pF, n =11) was reduced slightly with P >0 05, but I V curve remained morpholofically unchanged.The steady state inactivation curves were shifted to the hyperpolarizing direction in ischemic cells,the half maximal voltage dependence of inactivation(V1/2) in ischemic cells was (-25.9±7.0)mV in AMI after 1W ,(-21 3±5.6)mV in AMI after 2M and(-13.1±4.2)mV in the control cells respectively. There was a significant difference among them( P <0.05). Conclusions I Ca L was found Inhibitated in pericardial myocytes of ischemic zone. This might be one of the machnisma for development of ventricular arrythmia after AMI. Two months later,the abnormality of calcium currents was much more alleviated,showing a tendency of recovery.
出处
《华北国防医药》
2003年第1期5-7,共3页
Medical Journal of Beijing Military Region
关键词
心肌梗死
心室肌细胞
钙通道改变
实验研究
Myocardial infarction
Calcium current,L type
Patchclamp technique
Rabbits
