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目的探讨胺碘酮对急性心肌梗死(acute myocardial infarction,AMI)后梗死边缘区心肌细胞瞬间外向钾电流(transient outward potassium current,I_(to))的影响。方法30只兔随机分为3组,其中1组采用结扎左前降支的方法建立急性心肌梗死动物模型,其它2组为假手术组和正常对照组。1周后用膜片钳技术研究左心室梗死边缘区3层心肌细胞瞬间I_(to)的改变,并记录胺碘酮对I_(to)电流影响。结果正常对照组左室三层细胞的I_(to)存在跨壁异质性,+70 mV时心外膜层细胞(epicardial,Epi)的电流密度明显大于中层心室肌细胞及心内膜细胞(endocardium,Endo)(P<0.05);假手术组与对照组差异无统计学意义(P>0.05);急性心肌梗死组3层细胞I_(to)电流密度均降低,Epi与中层心室肌细胞、Endo之间差异有统计学意义(P<0.01);胺碘酮显著降低3层细胞I_(to)电流密度。结论左室心肌细胞的I_(to)存在跨壁异质性;心肌梗死对I_(to)的跨壁异质性有明显影响;胺碘酮减弱心肌梗死对I_(to)的跨壁异质性。
Objective To investigate the effect of amiodarone on the transient outward potassium current (I_ (to)) of myocardial cells in the infarct border area after acute myocardial infarction (AMI). Methods Thirty rabbits were randomly divided into three groups. One group was established by ligation of the left anterior descending artery in animal models of acute myocardial infarction. The other two groups were sham operation group and normal control group. One week later, patch clamp technique was used to study the change of I_ (to) of myocardial cells in the left ventricular infarction zone and the effect of amiodarone on I_ (to) current. Results There was transmural heterogeneity of I_ (to) in the left ventricular three-layer cells in normal control group. The current density of epicardial cells (Epi) at + 70 mV was significantly greater than that in middle ventricular myocytes and endocardial cells (P <0.05). There was no significant difference between the sham group and the control group (P> 0.05). The current density of 3-layer cells in the acute myocardial infarction group was decreased, while there was no difference between the Epi and the middle ventricular myocytes, Endo (P <0.01). Amiodarone significantly reduced the current density of three-layer cells. Conclusion Myocardial infarction has a significant effect on the transmural heterogeneity of I_ (to) in myocardial left ventricular myocytes. Amiodarone attenuates I_ (to) transmural heterogeneity Sex.