Na channel kinetics during the spontaneous heart beat in embryonic chick ventricle cells.
Na channel kinetics during the spontaneous heart beat in embryonic chick ventricle cells.
复制标题
胚胎鸡心室细胞自发心跳过程中的Na通道动力学。
DOI：
10.1016/s0006-3495(87)83192-2
复制
发表时间：
1987
影响因子：
3.4
通讯作者：
DeFelice,LJ
中科院分区：
文献类型：
--
作者：
Mazzanti,M;DeFelice,LJ
利用细胞附着和全细胞记录技术，可以同时测量心跳细胞动作电位期间的钠电流。在7 d雏鸡心室，Na的动态逆转电位为30 mV，比不跳动细胞的逆转电位小20 mV。这一结果表明，心脏细胞的自发活动将膜内表面的Na浓度提高到近40 mM。将Na作用电流拟合到霍奇金和赫胥利方程表明，贴片可能包含50到700个Na通道，平均密度为每微米23 +/- 21。在钠作用电流的峰值，只有大约2%的可用钠通道是打开的。这种低概率是在舒张期去极化阶段通道持续失活的结果。
Using cell-attached and whole-cell recording techniques simultaneously allows the measurement of Na currents during action potentials in beating heart cells. In 7-d chick ventricle, the dynamic reversal potential for Na is 30 mV, which is 20 mV less than the reversal potential in nonbeating cells. This result implies that the spontaneous activity of heart cells raises the Na concentration at the internal face of the membrane to nearly 40 mM. Fitting the Na action currents to the Hodgkin and Huxley equations shows that patches may contain from 50 to 700 Na channels, with an average density of 23 +/- 21 per micron2. Only approximately 2% of the available Na channels are open at the peak of the Na action current. This low probability is a consequence of the channels' continual inactivation during the diastolic depolarization phase.