Epithelial Sodium Channels

Epithelial sodium channels (ENaCs) are members of the ENaC/Deg (epithelial amiloride-sensitive Na+ channel and degenerin) family of ion channels. They are highly selective Na⁺ channels that are localized to polarized epithelial cells. ENaCs are responsible for sodium reabsorption in the distal kidney tubule, and have similar functions in the alveoli and the colon. These channels transport Na⁺ across the epithelium using energy from Na⁺, K⁺-ATPase, and constitute one of the essential mechanisms in regulation of sodium balance, blood volume and blood pressure.

There are four ENaC subunits; α, β, γ and δ, which form functional heterotetramers. The kidney ENaC is thought to be a heterotetramer of 2α:1β:1γ.

ENaCs are tonically open at rest. Ion flux is regulated by aldosterone-, vasopressin- and glucocorticoid-mediated changes in ENaC gene transcription and phosphatidylinositides act to stabilize the channel.

External sources of pharmacological information for Epithelial Sodium Channels :

• IUPHAR Receptor Code

Epithelial Sodium Channel Gene Data