Purpose Ion-driven transepithelial water fluxes participate in maintaining superficial vocal fold hydration, which is necessary for normal voice production. The authors hypothesized that Cl− channels are present in vocal fold epithelial cells and that transepithelial Cl− fluxes can be manipulated pharmacologically. Method Immunohistochemical assays were used to identify cystic fibrosis transmembrane regulator Cl− channels in ovine vocal fold mucosae (n = 2). Electrophysiological responses of vocal fold mucosae (n = 80) to Cl− channel inhibitors and secretagogues were evaluated in an ovine model using a randomized controlled experimental design. Results Cystic fibrosis transmembrane regulator channels were localized to the plasma membranes of epithelial cells. The Cl− transport inhibitor, diphenylamine-2-carboxylate, elicited a 30% decrease in mean short-circuit current (Isc; n = 10). The secretagogue, isobutylmethylxanthine, yielded a 31.7% increase in mean Isc (n = 10). Another secretagogue, uridine triphosphate, elicited a 48.8% immediate and 17.3% sustained increase in mean Isc (n = 10). No sustained increases occurred following application of secretagogues to mucosae bathed in a low Cl− environment (n = 10), suggesting that responses were Cl− dependent. Conclusions The authors provide structural and functional evidence for the presence of a transepithelial pathway for Cl− fluxes. Pharmacological manipulation of this pathway may offer a mechanism for maintaining superficial vocal fold hydration.
- Immunohistochemical assays,
- transepithelial pathway
Available at: http://works.bepress.com/ciara_leydon/7/