Eaton Douglas C, Helms My N, Koval Michael, Bao Hui Fang, Jain Lucky
Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Annu Rev Physiol. 2009;71:403-23. doi: 10.1146/annurev.physiol.010908.163250.
Amiloride-sensitive epithelial sodium channels (ENaC) play an important role in lung sodium transport. Sodium transport is closely regulated to maintain an appropriate fluid layer on the alveolar surface. Both alveolar type I and II cells have several different sodium-permeable channels in their apical membranes that play a role in normal lung physiology and pathophysiology. In many epithelial tissues, ENaC is formed from three subunit proteins: alpha, beta, and gamma ENaC. Part of the diversity of sodium-permeable channels in lung arises from assembling different combinations of these subunits to form channels with different biophysical properties and different mechanisms for regulation. Thus, lung epithelium has enormous flexibility to alter the magnitude of salt and water transport. In lung, ENaC is regulated by many transmitter and hormonal agents. Regulation depends upon the type of sodium channel but involves controlling the number of apical channels and/or the activity of individual channels.
氨氯地平敏感的上皮钠通道（ENaC）在肺钠转运中起重要作用。钠转运受到严格调节，以维持肺泡表面适当的液层。肺泡I型和II型细胞的顶端膜中都有几种不同的钠通透通道，它们在正常肺生理和病理生理中发挥作用。在许多上皮组织中，ENaC由三种亚基蛋白组成：α、β和γ ENaC。肺中钠通透通道的部分多样性源于这些亚基的不同组合组装，形成具有不同生物物理特性和不同调节机制的通道。因此，肺上皮在改变盐和水转运量方面具有极大的灵活性。在肺中，ENaC受多种递质和激素调节。调节取决于钠通道的类型，但涉及控制顶端通道的数量和/或单个通道的活性。
