Hydrogen sulfide as a regulator of respiratory epithelial sodium transport: the role of sodium-potassium ATPase. Focus on 'Hydrogen sulfide contributes to hypoxic inhibition of airway transepithelial sodium absorption'

摘要

central to the integrity of all organisms is the recognition of what is in (me) and what is out (not me). Many membrane-based activities are required to keep what is "me" differentiated and protected from what is "not me". Recognition of this difference between inside and outside and the importance of the regulatory processes needed to maintain the internal environment of the cell and extracellular space at stable and nonequi-librium values was essential to Walter Cannon's concept of homeostasis. Sodium-potassium ATPase (Na~+/K~+-ATPase) generates a nonequilibrium distribution of potassium and sodium across the cell membrane. This electrochemical gradient is used to power the transport or exchange of a large number of molecular homeostatic processes. In this issue of American Journal of Physiology-egulatory, Integrative and Comparative Physiology, Krause et al. (7) eloquently show that endogenous production of the gasotransmitter, H_2S, by airway epithelial cells significantly contributes to hypoxia-induced inhibition of epithelial sodium transport, specifically by inhibiting Na~+/K~+-ATPase activity.