增龄对犬左心房肌细胞动作电位和L型钙通道的影响.docVIP

 n 增龄对犬左心房肌细胞动作电位和 L 型钙 通道的影响# 甘天翊，许国军，汤宝鹏，周贤惠，李耀东，张健，李发鹏** 5 10 15 20 25 30 （新疆医科大学第一附属医院心脏中心，乌鲁木齐 830000） 摘要：目的 房颤随年龄的增加发病率增高，研究左心房电生理学特性是否存在增龄性改变。 方法 17 只杂种犬按年龄分为两组，成年犬 7 只，老年犬 10 只，用全细胞膜片钳的方法记 录成年犬和老年犬左心房肌细胞动作电位（AP）和 L 型钙电流(ICa.L),用实时荧光定量聚合 酶反应和蛋白免疫印迹的方法检测左心房肌 L 型钙通道 a1c 亚基(Cav1.2)的 mRNA 和蛋白表 达含量。结果 与成年犬相比，老年犬左心房肌细胞的动作电位平台期的幅度降低，动作电 位时程延长，ICa.L 电流密度降低。此外，与成年犬相比，老年犬左心房肌 Cav1.2 的 mRNA 和蛋白表达含量降低。结论 左心房肌细胞电生理学特性存在增龄性改变，这些改变增加房 颤发生的可能。 关键词：增龄；心房；钙电流；细胞电生理 中图分类号：R541.7 Changes in the aging-associated of action potential and L-type calcium channel of left atrial cells GAN Tianyi, XU Guojun, TANG baopeng, ZHOU Xianhui, LI Yaodong, ZHANG Jian, LI Fapeng (Department of Cardiology, First Affiliated Hospital, Xinjiang Medical University, Urumqi 830000) Abstract: Object: The aim of this study was to investigate whether the electrophysiological properties may be altered in aged left atrium.Mothods: 17 canines were allocated to two groups， seven adult canines and ten old canines．We used whole-cell patch-clamp to record action potential(AP) and L-type calcium current (ICa.L) in left atrial(LA) cells of adult and older canines.The a1c subunit of L-type calcium channel(Cav1.2) mRNA and protein expression were assessed by real-time quantitative RT-PCR and Western blotting respectively. Results: The plateau of AP was more negative and AP duration(APD) was longer in old tissue. Aged LA cells have lower peak ICa.L current densities than Adult LA cells. In addition, Compared to the adult group,the Cav1.2 mRNA and protein expression of LA were decreased in aged group. Conclusions: There are different aging-associated cell electrophysiological changes in the left atrium, These changes increased susceptibility of aged atria to atrial fibrillation. Keywords: Aging; Atria; Calcuim current; Cellar electrophysiology 35 0 引言 心房颤动（房颤）是临床最常见的心律失常之一，流行病学研究显示，人群中总房颤发 病率为 0．15％～1％，随年龄增加发病率升高，40 岁为 0．1％，65 岁达 6％，75 岁者 发病率达 10％。多项研究证实增龄是房颤的独立危险因素[1-3]。心房肌细胞电生理特性的变 40 化是房颤触发和维持的重要因素。因而研究与增龄相