A family of voltage-insensitive sodium-permeable ion channels that are inhibited by amiloride (compare voltage-gated sodium channels). In epithelia they constitute the rate-limiting step for sodium ion reabsorption. They are heterotrimers of highly homologous α, β, and γ subunits which also have homology with degenerins. Gain-of-function mutations in the β or γ subunits cause Liddle's disease. A δ subunit that will assemble with the β and γ subunits to form a functional channel is also known and is expressed mainly in ovary, testis, pancreas, and brain. See Apx/Shrm domains.
Subjects: Medicine and Health.