Regional differences in airway surface liquid composition

摘要: Liquid from canine airway surfaces was absorbed onto filter paper strips and analyzed. In resting conditions, tracheal surface liquid hyperosmolal (330 mosmol/kg H2O) compared to plasma with raised Na+ (158 meq/l), Cl- (134 K+ (28 HCO3- (32 meq/l) concentrations. The volume collected increased by repetitive sampling, a response blocked atropine, or methacholine injection. Compared nose breathing, osmolality 10 min of mouth breathing (410 H2O). Surface 0.5-cm diameter bronchi nearly isosmolal (304 in Na Cl concentrations lower than (120 106 meq/l, respectively), (52 (50 higher those liquid. Although the fluid approaches value for electrochemical equilibrium, both regions cannot be accounted passive forces. regional difference supports concept that reflects evaporative water loss this site. transepithelial osmotic gradient generated may driving force hydration surface.