Alterations of cardiac hemodynamics,sodium current and L-type calcium current in rats with L-thyroxine-induced cardiomyopathy
- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 4
- DOI:
- No doi available
- Key Word:
- L-甲状腺素;心肌病;血流动力学;INa;ICa-L;全细胞膜片钳
Abstract： 本文旨在研究L-甲状腺素(L-thyroxine,L-thy)所致的大鼠心肌病模型上血流动力学及心室肌细胞钠电流(INa)、L-钙通道电流(ICa-L)的变化.实验大鼠随机分成两组:心肌病组和对照组.心肌病组以0.5 mg/kg腹腔注射L-thy,连续注射10 d,建模成功后测定血流动力学变化,然后急性酶解法分离心肌细胞,应用全细胞膜片钳技术记录心肌细胞ICa-L.和ICa-L.结果显示:(1)与对照组相比,心肌病组大鼠左心室收缩压(left ventricular systolic pressure,LVSP)、左心室发展压(left ventricular developed pressure,LVDP)和左心室舒张期室内压最大下降速率(-dp/dtmax)均显著降低(P＜0.01),左心室收缩期室内压最大上升速率(+dp/dtmax)也表现为降低(P＜0.05),左心室舒张末期压(left ventricular end-diastolic pressure,LVEDP)显著升高(P＜0.01);(2)与对照组相比,在去极化电位为.30 mV时,心肌病组大鼠心肌细胞,INa电流密度由(-21.1±6.3)pA/pF增大至(-26.2±3.2)pA/pF(n=12,P＜0.01),INa的激活曲线左移,失活曲线左移,去失活曲线右移;(3)与对照组相比,在去极化电位为-10mV时,心肌病组大鼠心肌细胞,ICa-L电流密度由(-5.4±0.6)pA/pF增至(-7.9±0.8)pA/pF(n=12,P＜0.01),ICa-L的激活曲线左移,失活曲线左移,去失活曲线左移.以上结果表明,甲状腺素心肌病模型心功能与心力衰竭相似.其INa和ICa-L功能明显增强,尤其是ICa-L,L,提示在INa和ICa-L功能异常增强的心肌病治疗中若使用的钙通道拮抗剂带有降低心肌对Na+通透性的药物效果应更佳.
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