Epithelial Electrolyte Transport Physiology and the Gasotransmitter Hydrogen Sulfide

Figure 4

Airway epithelial ion transport responses to exogenous hydrogen sulfide. In airway surface epithelia, H₂S decreases basal absorption of Na⁺ and eventually water by decreasing the electrochemical driving forces for apical entry of Na⁺ through epithelial sodium channels (ENaC). This occurs by inhibition of the basolateral Na⁺/K⁺-ATPase as well as channels. Furthermore, exogenous H₂S prevents the translocation of subapical vesicles containing ENaCs to the membrane thereby abrogating the action of proabsorptive, cAMP-dependent stimuli.