Immunolocalization of aquaporins in vocal fold epithelia.
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.
Lodewyck
Danielle
D
Department of Communication Sciences and Disorders, Northwestern University, 2240 Campus Dr., Evanston, IL 60208, USA.
Menco
Bert
B
Fisher
Kimberly
K
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*
D000906:Antibodies; D051399:Aquaporin 2; D020346:Aquaporins; D051398:Aquaporin 1; D051400:Aquaporin 3