title: Effects of leukotriene C4 on the bioelectric properties and ion transport of equine tracheal epithelium.
abstract: OBJECTIVE
  To determine effects of leukotriene (LT) C(4) on ion transport across equine tracheal epithelium. Sample-Tracheal epithelium from cadavers of 24 horses considered free of respiratory tract disease.
  
  
  METHODS
  Mucosae were mounted into Ussing chambers, and short-circuit current (I(sc)) was monitored over time. Effects of LTC(4) were examined for various conditions, including addition of amiloride (10μM) to the mucosal bath solution, addition of bumetanide (10μM) to the serosal bath solution, addition of barium (1mM) to the serosal bath solution, and substitution of gluconate for chloride and HEPES for bicarbonate in bath solutions. Electrolyte transport was assessed via (22)Na and (36)Cl isotope fluxes.
  
  
  RESULTS
  Addition of LTC(4) (50nM) to the serosal bath solution caused an increase in I(sc) for basal conditions and a larger increase after pretreatment with amiloride. The increase was negated in part by the addition of bumetanide to the serosal bath solution and further reduced by substitution of HEPES for bicarbonate in bath solutions. Remaining current was reduced to values less than those before treatment with LTC(4) by the addition of barium to the serosal solution. There was a small increase in I(sc) after the addition of amiloride and substitution of gluconate for chloride. Radioisotope flux indicated that addition of LTC(4) to the serosal bath solution increased chloride secretion and reduced sodium absorption.
  
  
  CONCLUSIONS
  LTC(4) stimulated chloride secretion through a predominately bumetanide-sensitive pathway, with a smaller contribution from a bicarbonate-dependent pathway. Thus, LTC(4) appears to be a potential mediator of airway hypersecretion in horses.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA. G.Lester@murdoch.edu.au
authors.forename: Guy D
authors.initials: GD
authors.lastname: Lester
authors.forename: Brett L
authors.initials: BL
authors.lastname: Rice
mesh_terms: D000818:Animals; D001464:Barium / Q000494:pharmacology; D001639:Bicarbonates / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D004553:Electric Conductivity; D004848:Epithelium / Q000378:metabolism; D006736:Horses / Q000378:metabolism*; D017136:Ion Transport; D017997:Leukotriene C4 / Q000378:metabolism*; D009092:Mucous Membrane / Q000378:metabolism; D009930:Organic Chemicals / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D012964:Sodium / Q000378:metabolism; D014132:Trachea / Q000378:metabolism*
chemical_list: D001639:Bicarbonates; D002712:Chlorides; D009930:Organic Chemicals; D001464:Barium; D017997:Leukotriene C4; D012964:Sodium