Connexins in the sinoatrial and atrioventricular nodes
Connexins in the sinoatrial and atrioventricular nodes
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DOI：
10.1159/000092569
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发表时间：
2006-01-01
期刊：
影响因子：
--
通讯作者：
Dobrzynski, H.
中科院分区：
文献类型：
--
作者：
Boyett, M. R.;Inada, S.;Dobrzynski, H.
窦房结 (SAN) 和房室结 (AVN) 是心脏中的特殊组织：SAN 专门用于起搏（它是心脏的起搏器），而 AVN 专门用于动作电位的缓慢传导（在心动周期期间在心房和心室激活之间引入延迟）。这些功能对电耦合有特殊要求，因此对连接蛋白亚型的表达有特殊要求。 SAN 中心的电耦合应该较弱，以保护其免受 SAN 周围更加超极化的非起搏心房肌的抑制性电紧张影响。然而，为了使 SAN 能够驱动心房肌，SAN 外围的电耦合应该很强。与此一致的是，在 SAN 的中心，没有 Cx43（工作心肌的主要连接蛋白）的表达，也很少有 Cx40 的表达，但有 Cx45 和 Cx30.2 的表达，而在 SAN 的外围，Cx43 也有 Cx45 的表达。在 AVN 中，连接蛋白的表达模式与 SAN 中心相似，这可能在很大程度上导致动作电位传导缓慢。版权所有 (c) 2006 S. Karger AG，巴塞尔。
The sinoatrial node (SAN) and the atrioventricular node (AVN) are specialized tissues in the heart: the SAN is specialized for pacemaking (it is the pacemaker of the heart), whereas the AVN is specialized for slow conduction of the action potential (to introduce a delay between atrial and ventricular activation during the cardiac cycle). These functions have special requirements regarding electrical coupling and, therefore, expression of connexin isoforms. Electrical coupling in the center of the SAN should be weak to protect it from the inhibitory electrotonic influence of the more hyperpolarized non-pacemaking atrial muscle surrounding the SAN. However, for the SAN to be able to drive the atrial muscle, electrical coupling should be strong in the periphery of the SAN. Consistent with this, in the center of the SAN there is no expression of Cx43 (the principal connexin of the working myocardium) and little expression of Cx40, but there is expression of Cx45 and Cx30.2, whereas in the periphery of the SAN Cx43 as well Cx45 is expressed. In the AVN, there is a similar pattern of expression of connexins as in the center of the SAN and this is likely to be in large part responsible for the slow conduction of the action potential. Copyright (c) 2006 S. Karger AG, Basel.