title: Immunolocalization of aquaporins in vocal fold epithelia.
abstract: OBJECTIVE
  To investigate the presence of aquaporin (AQP) water channels 1, 2, and 3 in stratified squamous vocal fold epithelium.
  
  
  METHODS
  Immunolocalization analysis of excised ovine vocal fold epithelia.
  
  
  METHODS
  Sheep.
  
  
  METHODS
  Ovine vocal fold epithelia were prepared for immunoelectron microscopy using primary antibodies directed against AQP-1, AQP-2, and AQP-3. Photographic profiles of epithelium exposed to each antibody were used to calculate the immunogold labeling density of the plasma membrane and cytoplasm.
  
  
  METHODS
  Density of immunolabeling was compared across 3 regions that represent cell layers closest to the glottal lumen for the plasma membrane and cytoplasm, respectively.
  
  
  RESULTS
  Labeling densities of AQP-1 and AQP-2 were significantly greater for the plasma membrane region of the luminal cells than for deeper cell layers. Cytoplasmic labeling and labeling of circular structures was greatest for cell layers 2 through 5 beneath the vocal fold surface compared with the surface cell layer. Immunogold labeling of AQP-3, an aquaglyceroporin, in vocal fold epithelium was inconclusive.
  
  
  CONCLUSIONS
  Aquaporins 1 and 2, associated with the plasma membrane region of ovine vocal fold epithelial cells, demonstrate the presence of an intrinsic mechanism to permit transcellular water flux in response to osmotic gradients.
authors.affiliation: Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Dr., Evanston, IL 60208, USA.
authors.forename: Danielle
authors.initials: D
authors.lastname: Lodewyck
authors.forename: Bert
authors.initials: B
authors.lastname: Menco
authors.forename: Kimberly
authors.initials: K
authors.lastname: Fisher
mesh_terms: D000818:Animals; D000906:Antibodies; D051398:Aquaporin 1 / Q000032:analysis; D051399:Aquaporin 2 / Q000032:analysis; D051400:Aquaporin 3 / Q000032:analysis; D020346:Aquaporins / Q000648:ultrastructure*; D002462:Cell Membrane / Q000648:ultrastructure; D003593:Cytoplasm / Q000648:ultrastructure; D004847:Epithelial Cells / Q000166:cytology; D005931:Glottis / Q000166:cytology; D007150:Immunohistochemistry; D016253:Microscopy, Immunoelectron; D012756:Sheep; D014827:Vocal Cords / Q000166:cytology*
chemical_list: D000906:Antibodies; D051399:Aquaporin 2; D020346:Aquaporins; D051398:Aquaporin 1; D051400:Aquaporin 3