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兔左室各层心肌细胞快钠通道特性的跨壁异质性(PDF)

《心脏杂志》[ISSN:1009-7236/CN:61-1268/R]

期数:
2003年第6期
页码:
481-484
栏目:
实验研究
出版日期:
2003-11-01

文章信息/Info

Title:
Transmural heterogeneity of the sodium current among epicardial, midmyocardial and endocardial myocytes from rabbit left ventricles
作者:
齐书英1; 刘坤申2; 胡丽叶1; 杨丽1; 刘小云1; 张铁军1; 李信政1
1.白求恩国际和平医院心内科, 河北 石家庄 050082; 2.河北医科大学第一附属医院心内科, 河北 石家庄050017
Author(s):
QI Shu-ying1;  LIU Kun-shen2;  HU Li-ye1;  YANG Li1;  LIU Xiao-yun1;  ZHANG Tie-jun1;  LI Xin-zheng1
1.Department of Cardiology, Bethune International Peace Hospital, Shijiazhuang, Hebi 050082, China
关键词:
兔; 左心室; 快钠电流; 异质性; 膜片钳技术
Keywords:
rabbit;  left ventricle;  fast sodium current;  heterogeneity;  patch clamp technique
分类号:
R331.38
DOI:
-
文献标识码:
A
摘要:
目的:研究新西兰纯种大白兔左心室游离壁3 层心肌细胞的形态特征及其快钠通道电流(INa)特性的异质性。方法:采用胶原酶酶解法分离兔左室游离壁3 层心肌细胞, 以全细胞膜片钳技术记录快钠电流的动力学特性。结果: ①兔左室游离壁3 层心肌细胞的形态特征相似; ②3 层细胞的IN a I2V 曲线均呈电压依赖性, 形态轨迹一致。3层细胞中M 细胞的I2V 曲线最低, 心内膜和心外膜层的依次向上。INa峰值电流密度在-20mV时M, Epi和Endo细胞分别为- 31±8、-16±7 和-12±2pA?pF(n=12cells),M 细胞的INa电流密度明显大于Epi、Endo。M细胞的INa稳态失活曲线在最左边, 向右依次为Epi和Endo细胞,M的INa失活最快。3 层细胞的IN a失活后恢复曲线无显著性差异。结论: 兔左室游离壁3 层心肌细胞的形态特征相似, IN a的分布及动力学特性存在异质性, 可能是动作电位形态的差异和折返性心律失常发生的离子基础。
Abstract:
AIM: To study the features of the sodium current (INa) of epicardial, midmyocardial and endocardial myocytes from rabbit left ventricles. METHODS: Single myocyte was dissociated enzymatically and INa was recorded using who le-cell patch clamp techniques. RESULTS: The INa current density-voltage relation ship was voltage-dependent. Among the three groups, midmyocardial cells had the largest, and epicardial cells the smallest I-V curves. The peak IN a densities of the M, Endo and Epi at -20mV were -31±8, -16±7 and -12±2pA ?p F(n=12cells). The peak INa density was greater in the M cells than in the Epi and Endo cells (P=0.000 and 0.001, respectively). The INa steady-inactivation curves of the Epi, M and Endo cells were voltage-dependent and shaped as“reverse S”type. Among the three groups, M cells inactivated faster than the other two groups. There were no significant differences in the INa recovery curves from inactivation among the three types of myocytes. CONCLUSION: The morphological characteristics of Epi, M and Endo cells are similar. The transmural heterogeneity of INa may be the ionic bases of the differences in morphology of the action potentials among three types of myocytes, and may be responsible for some reentant arrhythmias.

参考文献/References

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[9] Antzelevitch C, Sicouri S, Litovsky SH, et al. Heterogeneity with in the ventricular wall: electrophysiology and pharmacology of epicardial, endocardial and M cells [J] . Circ Res, 1991, 69:1427-49.

[10] Antzelevitch C, Sicouri S, Litovsky SH, et al. Heterogeneity with in the ventricular wall: electrophysiology and pharmacology of epicardial, endocardial and M cells [J]. Circ Res, 1991, 69:1427-49.

备注/Memo

备注/Memo:
收稿日期：2002-12-20.
更新日期/Last Update: 2003-11-01