Atrial cardiomyocyte calcium signalling
Atrial cardiomyocyte calcium signalling
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DOI：
10.1016/j.bbamcr.2011.01.030
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发表时间：
2011-05-01
影响因子：
5.1
通讯作者：
Roderick, H. Llewelyn
中科院分区：
文献类型：
--
作者：
Bootman, Martin D.;Smyrnias, Ioannis;Roderick, H. Llewelyn
尽管心室心肌细胞中的Ca（2+）信号传导已被充分描述，但关于心房细胞中的Ca（2+）信号的了解要少得多。这是令人惊讶的，因为心房心肌细胞对心室的血液再填充做出了重要贡献，这增强了随后血液从心脏的喷射。随着年龄的增长和运动，心脏功能对心房贡献的依赖性变得越来越重要。心房心肌细胞节律性搏动的中断可导致危及生命的疾病，如心房纤颤。心房和心室肌细胞在结构和功能上有许多相似之处。然而，一个关键的结构差异，即心房肌细胞中缺乏横小管（“T-小管”），使得这两种细胞类型响应于电刺激显示出截然不同的钙模式。心房肌细胞中缺乏T-小管意味着去极化引起起源于细胞周围的钙信号。在静息状态下，这种Ca（2+）信号不会向心房细胞的中心传播，因此不会完全参与收缩机制。因此，静息状态下心房肌细胞的收缩是适度的。然而，当用正性肌力激动剂（如异丙肾上腺素）刺激心房肌细胞时，外周Ca（2+）信号触发Ca（2+）的整体波，以向心方式传播到细胞中。心房肌细胞中Ca（2+）的向心运动增强导致收缩增加和对血液泵送的更实质性贡献。这篇文章是题为：第11届欧洲钙研讨会特刊的一部分。(C)2011 Elsevier B. V.保留所有权利。
Whereas Ca(2+) signalling in ventricular cardiomyocytes is well described, much less is known regarding the Ca(2+) signals within atrial cells. This is surprising given that atrial cardiomyocytes make an important contribution to the refilling of ventricles with blood, which enhances the subsequent ejection of blood from the heart. The dependence of cardiac function on the contribution of atria becomes increasingly important with age and exercise. Disruption of the rhythmic beating of atrial cardiomyocytes can lead to life-threatening conditions such as atrial fibrillation. Atrial and ventricular myocytes have many structural and functional similarities. However, one key structural difference, the lack of transverse tubules ("T-tubules") in atrial myocytes, make these two cell types display vastly different calcium patterns in response to electrical excitation. The lack of T-tubules in atrial myocytes means that depolarisation provokes calcium signals that originate around the periphery of the cells. Under resting conditions, such Ca(2+) signals do not propagate towards the centre of the atrial cells and so do not fully engage the contractile machinery. Consequently, contraction of atrial myocytes under resting conditions is modest. However, when atrial myocytes are stimulated with a positive inotropic agonist, such as isoproterenol, the peripheral Ca(2+) signals trigger a global wave of Ca(2+) that propagates in a centripetal manner into the cells. Enhanced centripetal movement of Ca(2+) in atrial myocytes leads to increased contraction and a more substantial contribution to blood pumping. This article is part of a Special Issue entitled: 11th European Symposium on Calcium. (C) 2011 Elsevier B.V. All rights reserved.