Hervé J-C, Derangeon M, Théveniau-Ruissy M, Miquerol L, Sarrouilhe D, Gros D
Institut de physiologie et de biologie cellulaire, UMR 6187, CNRS-université de Poitiers, 40, avenue du Recteur-Pineau, 86022 Poitiers cedex, France.
Pathol Biol (Paris). 2008 Jul;56(5):334-41. doi: 10.1016/j.patbio.2008.05.009. Epub 2008 Jun 30.
The electrical activity in heart is generated in the sinoatrial node and then propagates to the atrial and ventricular tissues. The junctional channels that couple the cardiomyocytes are responsible for this propagation process. These channels are dodecamers of transmembrane proteins of the connexin (Cx) family. Four Cxs - Cx30.2, -40, -43 and -45--have been demonstrated to be synthesized in the cardiomyocytes. In addition, each of these Cxs has a unique expression pattern in the myocardium. A fruitful approach of the role of these Cxs in the cardiac functions came with the development of transgenic mouse models. It has been shown that Cx43 was mainly involved in influx propagation in the ventricles and that inactivation in the cardiomyocytes of the gene of this Cx predisposed to development of cardiac abnormalities. Cx40 very significantly contributes to the propagation of electrical activity in the atria and the conduction system. Cx45 is essential to coordinate the synchronization of contractile activities of embryonic cardiomyocytes and for the normal progress of cardiogenesis. Finally, Cx30.2 contributes to the slowing of propagation of excitation in the atrioventricular node. These observations enable to better understand the relationships between alteration in Cx expression or gap junction remodelling and arrhythmias in the human heart.
心脏的电活动在窦房结产生，然后传播到心房和心室组织。连接心肌细胞的连接通道负责这一传播过程。这些通道是连接蛋白（Cx）家族跨膜蛋白的十二聚体。已证实心肌细胞中合成四种Cx——Cx30.2、Cx40、Cx43和Cx45。此外，这些Cx中的每一种在心肌中都有独特的表达模式。随着转基因小鼠模型的发展，研究这些Cx在心脏功能中的作用有了富有成效的方法。已表明Cx43主要参与心室中的电活动传播，该Cx基因在心肌细胞中的失活易导致心脏异常的发生。Cx40对心房和传导系统中的电活动传播有非常显著的作用。Cx45对于协调胚胎心肌细胞收缩活动的同步以及心脏发生的正常进程至关重要。最后，Cx30.2有助于减慢房室结中兴奋的传播。这些观察结果有助于更好地理解人类心脏中Cx表达改变或缝隙连接重塑与心律失常之间的关系。
