The contribution of epithelial sodium channels to alveolar function in health and disease.
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.
Eaton
Douglas C
DC
Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA. deaton@emory.edu
Helms
My N
MN
Koval
Michael
M
Bao
Hui Fang
HF
Jain
Lucky
L
D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002463:Cell Membrane Permeability / Q000502:physiology; D053503:Epithelial Sodium Channels / Q000502:physiology*; D006801:Humans; D008171:Lung Diseases / Q000503:physiopathology*; D011650:Pulmonary Alveoli / Q000166:cytology / Q000502:physiology*; D012964:Sodium / Q000378:metabolism; D019108:Tight Junctions / Q000502:physiology
D053503:Epithelial Sodium Channels; D012964:Sodium