摘要
目的 研究单个肺静脉肌袖心肌细胞动作电位、短暂外向钾电流 (Ito)及L型钙通道电流 (ICa L)特性 ,及其与心房心肌细胞的特性比较。方法 全细胞膜片钳技术。结果 肺静脉肌袖心肌细胞与心房心肌细胞动作电位、Ito特性差异无显著性 ,但前者ICa L较后者小 ;异丙肾上腺素灌注后 ,两种心肌细胞呈现显著的电生理差异 ,前者APD90 和APD50 增大 ,Ito减小 ,而后者APD90 和APD50 减小 ,Ito增大 ;二者ICa L均增大 ,前者增大幅度较后者显著。结论 肺静脉肌袖心肌细胞与心房心肌细胞存在离子流特性的差异 ,这一电生理的异质性可被异丙肾上腺素或交感神经兴奋影响 ,可能参与心房颤动的触发或驱动。
Objective To investigate the characteristics of action potential (AP), transient outward potassium current ( I _ to ), calcium current ( I _ Ca-L )of the myocytes in rabbit pulmonary vein and to compare these characteristics with those of the atrial myocytes. Methods The technique of patch clamp was used. Results There was no difference of AP and I _ to between myocytes in pulmonary vein and in atrium, but the peak current of I _ Ca-L at +10mV was smaller in myocytes of pulmonary vein than that of atrium [(0.07±0.03) nA vs (1.60±0.66)nA].After isoprenaline infusion, APD_ 90 and APD_ 50 were prolonged in myocytes of pulmonary vein [(194.83±39.61)ms vs (277.08±51.37) ms; (61.69±5.75)ms vs (110.66±13.7)ms] but were reduced in myocytes of atrium [(133.88±20.46)ms vs (108.55±14.66)ms ; (72.71±21.76)ms vs (54.94±14.72)ms]; I _ to at +40mV was increased in myocytes of pulmonary vein[(3.97±0.63)nA vs (3.07±0.35)nA] but decreased in myocytes of atrium [(4.0±0.66)nA vs (4.72±0.51)nA]; I _ Ca-L was increased to (0.19±0.03) pA in the myocytes of pulmonary vein and (2.96±0.83)nA in myocytes of atrium. Conclusions There are differences in ion currents between myocytes of pulmonary vein and atrium. The electrophysiological heterogeneities can be influenced by isoprenaline or sympathetic nerve activation and may be involved in triggering atrial fibrillation.
出处
《中华心血管病杂志》
CAS
CSCD
北大核心
2002年第4期232-234,共3页
Chinese Journal of Cardiology
