title: Actions of hydrogen sulfide on sodium transport processes across native distal lung epithelia (Xenopus laevis).
abstract: Hydrogen sulfide (H2S) is well known as a highly toxic environmental chemical threat. Prolonged exposure to H2S can lead to the formation of pulmonary edema. However, the mechanisms of how H2S facilitates edema formation are poorly understood. Since edema formation can be enhanced by an impaired clearance of electrolytes and, consequently, fluid across the alveolar epithelium, it was questioned whether H2S may interfere with transepithelial electrolyte absorption. Electrolyte absorption was electrophysiologically measured across native distal lung preparations (Xenopus laevis) in Ussing chambers. The exposure of lung epithelia to H2S decreased net transepithelial electrolyte absorption. This was due to an impairment of amiloride-sensitive sodium transport. H2S inhibited the activity of the Na+/K+-ATPase as well as lidocaine-sensitive potassium channels located in the basolateral membrane of the epithelium. Inhibition of these transport molecules diminishes the electrochemical gradient which is necessary for transepithelial sodium absorption. Since sodium absorption osmotically facilitates alveolar fluid clearance, interference of H2S with the epithelial transport machinery provides a mechanism which enhances edema formation in H2S-exposed lungs.
authors: Institute of Animal Physiology, Justus-Liebig University of Giessen, Giessen, Germany.
authors: Alexandra
authors: A
authors: Erb
authors: Institute of Animal Physiology, Justus-Liebig University of Giessen, Giessen, Germany.
authors: Mike
authors: M
authors: Althaus
mesh_terms: D000818:Animals; D004573:Electrolytes / Q000378:metabolism; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D015221:Potassium Channels / Q000378:metabolism / Q000502:physiology; D011654:Pulmonary Edema / Q000139:chemically induced; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism / Q000502:physiology; D014982:Xenopus laevis
chemical_list: D004573:Electrolytes; D015221:Potassium Channels; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D006862:Hydrogen Sulfide