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Hypoxia pp 305-314 | Cite as

Structure function relationships of ENaC and its role in sodium handling

  • Laurent Schild
  • Stephan Kellenberger
Chapter
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 502)

Abstract

The epithelial sodium channel (ENaC) in the apical membrane of polarized epithelial cells is the rate-limiting step for Na entry into the cell; in series with the basolateral Na pump, it allows the vectorial transepithelial transport of Na ions. ENaC is expressed in different epithelia like the distal nephron or colon, and the airways epithelium. In the lung ENaC controls the composition and the amount of pulmonary fluid, whereas in the distal nephron ENaC under the control of aldosterone and vasopressin, is essential to adapt the amount of Na+ reabsorbed with the daily sodium intake. Activating mutations of ENaC cause severe disturbances of Na+ homeostasis leading to hypertension in human and in mouse models. Functional expression of ENaC in different cell systems allowed the identification of structural domains of the protein that are essential for channel function and/or modulation of channel activity. Site-directed mutations in specific domains of the channel protein lead to channel hyperactivity or channel loss of function. Knowledge about ENaC structure-function relationships opens new opportunities for development of pharmacological tools for controlling ENaC activity, such as channel activators of potential benefit in the treatment of pulmonary edema, or highly potent ENaC blockers with natriuretic effects.

Key words

Epithelial Na+ transport epithelial sodium channel ENaC aldosterone amiloride 

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Copyright information

© Springer Science+Business Media New York 2001

Authors and Affiliations

  • Laurent Schild
    • 1
  • Stephan Kellenberger
    • 1
  1. 1.Institut de Pharmacologie et Toxicologie de l’UniversitéLausanneSwitzerland

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