Chloride and potassium channel function in alveolar epithelial cells

Electrolyte transport across the adult alveolar epithelium plays an important role in maintaining a thin fluid layer along the apical surface of the alveolus that facilitates gas exchange across the epithelium. Most of the work published on the transport properties of alveolar epithelial cells has focused on the mechanisms and regulation of Na+ transport and, in particular, the role of amiloride-sensitive Na+ channels in the apical membrane and the Na+-K+- ATPase located in the basolateral membrane. Less is known about the identity and role of Cl- and K- channels in alveolar epithelial cells, but studies are revealing important functions for these channels in regulation of alveolar fluid volume and ionic composition. The purpose of this review is to examine previous work published on Cl- and K+ channels in alveolar epithelial cells and to discuss the conclusions and speculations regarding their role in alveolar cell transport function.