Functional Domains of the Epithelial Sodium Channel

[摘要] The epithelial sodium channel (ENaC) plays an important role in ion transport of many organ systems. In kidney, colon, and sweat gland, ENaC-mediated transepithelial sodium transport helps to adjust sodium excretion in the urine, feces, and sweat to fulfill homeostatic requirements. In lung and airways, ENaC activity is important for alveolar liquid clearance and regulation of mucous fluidity. In the taste buds of the tongue, ENaC is likely involved in salt tasting, whereas ENaC expression in the eye and inner ear may help to control the ionic composition of the aqueous humor and the endolymph, respectively. These diverse functions of ENaC (1) require intricate molecular regulatory systems that precisely adapt ENaC function to constantly changing electrolyte transport requirements. The best studied regulatory system is the aldosterone-dependent regulation of ENaC in the kidney, which is of major importance for the maintenance of whole-body sodium homeostasis and for BP control (2). This review focuses exclusively on the role of ENaC in renal sodium handling. Distribution and aldosterone-dependent regulation of ENaC in the kidney in vivo is discussed briefly, and the functional domains of ENaC that are important for the regulation of the channel under physiologic and pathophysiologic conditions are highlighted.

[学科分类] 泌尿医学

[关键词] Bone marrow necrosis;Sickle cell disease;Hyperhemolysis syndrome