Diminished transient outward currents in rat hypertrophied ventricular myocytes.
Diminished transient outward currents in rat hypertrophied ventricular myocytes.
复制标题
大鼠肥大心室肌细胞的瞬时外向电流减少。
DOI：
10.1161/01.res.75.2.296
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发表时间：
1994
影响因子：
20.1
通讯作者：
Kimura,S
中科院分区：
文献类型：
--
作者：
Tomita,F;Bassett,AL;Myerburg,RJ;Kimura,S
持续压力超负荷所致的心室肥厚，动作电位时程延长。由于瞬时外向电流(I(TO))是决定大鼠心室肌细胞动作电位时程的主要因素，我们采用膜片钳技术比较了正常和肥厚大鼠左心室细胞I(TO)的特性。研究前采用部分结扎腹主动脉4~6周的方法造成左心室压力超负荷。以年龄匹配的正常大鼠为对照。压力超负荷使心脏重量/体重比增加47.7%。肥厚细胞的I(TO)显著小于正常细胞(分别为20.0+/-1.3和31.0+/-2.1 pA/pF，测试电位为+60 mV；P<；.001)。正常和肥大细胞的稳态失活、失活时间和失活恢复时间无明显差异。在单通道水平，正常细胞和肥厚细胞的单个I(To)通道的单位电流幅度无差异，斜率电导正常细胞为13.7皮西姆，肥厚细胞为13.4皮西姆。最大开放概率由整体平均电流峰值与单通道电流幅度之比估计，正常细胞和肥厚细胞的最大开放概率相似(分别为0.66+/-0.03和0.69+/-0.04，测试电位为+40 mV；P=NS)。我们的结论是，I(TO)的减少有助于压力超负荷大鼠肥厚的心肌细胞动作电位的延长。降低的I(TO)信道密度可能是整个小区I(TO)减小的原因。
Action potential duration is prolonged in ventricular hypertrophy induced by sustained pressure overload. Since the transient outward current (I(to)) is a major factor for determining action potential duration in rat ventricular cells, we used patch-clamp techniques to compare the characteristics of I(to) in normal and hypertrophied left ventricular cells of the rat. Left ventricular pressure overload was induced by partial ligation of the abdominal aorta for 4 to 6 weeks before study. Age-matched normal rats served as controls. Pressure overload increased the heart weight-to-body weight ratio by 47.7%. I(to) was significantly smaller in hypertrophied cells than in normal cells (20.0 +/- 1.3 versus 31.0 +/- 2.1 pA/pF, respectively, at a test potential of +60 mV; P < .001). There were no differences in the steady-state inactivation, the inactivation time course, and the time course of recovery from inactivation between normal and hypertrophied cells. At the single-channel level, there were no differences in the unitary current amplitude of the single I(to) channel between normal and hypertrophied cells, and the slope conductance was 13.7 picosiemens in normal cells and 13.4 picosiemens in hypertrophied cells. The maximum open-state probability, which was estimated from the ratio of the peak of the ensemble-averaged currents to the single-channel current amplitude, was similar for normal and hypertrophied cells (0.66 +/- 0.03 and 0.69 +/- 0.04, respectively, at a test potential of +40 mV; P = NS). We conclude that diminished I(to) contributes to action potential prolongation in hypertrophied ventricular cells from pressure-overloaded rat hearts. Reduced I(to) channel density may be responsible for the diminished whole-cell I(to).
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影响因子：
20.1
作者：
TSENG, GN;HOFFMAN, BF
通讯作者：
HOFFMAN, BF
影响因子：
3.5
作者：
J. Tseng-Crank;G. Tseng;A. Schwartz;M. Tanouye
通讯作者：
J. Tseng-Crank;G. Tseng;A. Schwartz;M. Tanouye
DOI：
10.1152/ajpheart.1989.256.4.h1006
发表时间：
1989
期刊：
The American journal of physiology
影响因子：
--
作者：
Kimura,S;Bassett,AL;Saida,K;Shimizu,M;Myerburg,RJ
通讯作者：
Myerburg,RJ
影响因子：
20.1
作者：
LIU, DW;GINTANT, GA;ANTZELEVITCH, C
通讯作者：
ANTZELEVITCH, C
兔心室肌细胞膜上的单个延迟整流通道。
影响因子：
20.1
作者：
M. Veldkamp;G. AntoniC.;van;Ginneken;Lennart N. Bouman
通讯作者：
Lennart N. Bouman