Epithelial sodium channel

The epithelial sodium channel (short: ENaC, also: sodium channel non-neuronal 1 (SCNN1) or amiloride sensitive sodium channel (ASSC)) is a membrane-bound ion-channel that is permeable for Li⁺-ions, protons and especially Na⁺-ions. It is a constitutively active ion-channel. It is arguably the most selective ion channel.

The apical membrane of many tight epithelia contains sodium channels that are primarily characterised by their high affinity to the diuretic blocker amiloride. In vertebrates, the channels control reabsorption of sodium in kidney, colon, lungand sweat glands; they also play a role in taste perception.

Location and function

ENaC is located in the apical membrane of polarized epithelial cells particularly in the kidney (primarily in the collecting tubules), the lung and the colon. It is involved in the transepithelial Na⁺-ion transport, which it accomplishes together with the Na⁺/K⁺-ATPase.

It plays a major role in the Na⁺- and...
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