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Functional roles of sodium-calcium exchange in autorhythmicity and action potential of murine fetal cardiomyocytes at early developmental stage

LUO Hong-Yan¹, HU Xin-Wu¹, ZHANG Liang-Pin¹, ZENG Ying², GUAN Xiu-Wen^3,*

¹tment of Physiology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan 430030, China；²Wuhan Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China；³The People's Hospital of Huangpi District, Wuhan 430300, China

Abstract

The aim of the present paper was to study the role of sodium calcium exchanger (NCX) in the generation of action potentials (APs) in cardiomyocytes during early developmental stage (EDS). The precisely dated embryonic hearts of C57 mice were dissected and enzymatically dissociated to single cells. The changes of APs were recorded by whole-cell patch-clamp technique before and after administration of NCX specific blockers KB-R7943 (5 μmol/L) and SEA0400 (1 μmol/L). The results showed that, both KB-R7943 and SEA0400 had potent negative chronotropic effects on APs of pacemaker-like cells, while such effects were only observed in some ventricular-like cardiomyocytes. The negative chronotropic effect of KB-R7943 on ventricular-like cardiomyocytes was accompanied by shortening of AP duration (APD), whereas such an effect of SEA0400 was paralleled by decrease in velocity of diastolic depolarization (Vdd). From embryonic day 9.5 (E9.5) to E10.5, the negative chronotropic effects of KB-R7943 and SEA0400 on ventricular-like APs of embryonic cardiomyocytes gradually disappeared. These results suggest that, in the short-term development of early embryo, the function of NCX may experience developmental changes as evidenced by different roles of NCX in autorhythmicity and APs generation, indicating that NCX function varies with different conditions of cardiomyocytes.

Key words: SEA0400; KB-R7943; sodium calcium exchanger; fetal cardiomyocytes; action potential

Received: 2019-12-24　　Accepted: 2020-04-17

Corresponding author: 关秀文　　E-mail: 329703831@qq.com

DOI: 10.13294/j.aps.2020.0086

Citing This Article：

LUO Hong-Yan, HU Xin-Wu, ZHANG Liang-Pin, ZENG Ying, GUAN Xiu-Wen. Functional roles of sodium-calcium exchange in autorhythmicity and action potential of murine fetal cardiomyocytes at early developmental stage. Acta Physiol Sin 2020; 72 (6): 757-764