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Dynamic changes of electrical remodeling in midmyocardium of rabbit left ventricle during the early stage of chronic pressure-overload
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- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 3
- DOI:
- 10.3321/j.issn:0371-0874.2009.03.003
- Key Word:
- 膜片钳技术;心室重构;离子通道
Abstract： 我们以往的研究发现,慢性压力超负荷致心室肌细胞肥大过程中,中层细胞动作电位时程(action potential duration,APD)逐渐延长且易发生早期后除极(early after-depolarization,EAD).在本实验中,我们应用全细胞膜片钳技术进一步观察慢性压力超负荷早期兔左心室肌中层细胞电重构的动态变化,并探讨此变化的病理生理学意义.取新西兰兔64只,随机分为缩窄组和假手术组,采用肾上腹主动脉缩窄术制备兔左心室压力超负荷模型.分别在术后2周和8周采用胶原酶两步消化法分离获取左心室中层单个心肌细胞,全细胞膜片钳技术记录中层细胞慢激活延迟整流钾电流(IKs)、瞬间外向钾电流(Ito)及L型钙电流(ICa-L).结果显示,术后2周,与假手术组比较,缩窄组中层细胞IKs尾电流(IKs,tail)密度降低33.3%,Ito密度降低51.5%,ICa-L密度无明显改变;术后8周,与假手术组比较,缩窄组中层细胞IKs,tail密度降低37.0%,Ito密度降低49.2%,ICa-L密度仍无明显改变.上述结果提示,在慢性压力超负荷的早期,兔左心室肌中层细胞电生理特性即发生明显改变,表现为IKs和Ito下调,导致APD延长,可能与恶性心律失常发生有关.
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