title: Cyclic adenosine monophosphate regulation of ion transport in porcine vocal fold mucosae.
abstract: OBJECTIVE
  Cyclic adenosine monophosphate (cAMP) is an important biological molecule that regulates ion transport and inflammatory responses in epithelial tissue. The present study examined whether the adenylyl cyclase activator, forskolin, would increase cAMP concentration in porcine vocal fold mucosa and whether the effects of increased cAMP would be manifested as a functional increase in transepithelial ion transport. Additionally, changes in cAMP concentrations following exposure to an inflammatory mediator, tumor necrosis factor-alpha (TNFalpha) were investigated.
  
  
  METHODS
  In vitro experimental design with matched treatment and control groups.
  
  
  METHODS
  Porcine vocal fold mucosae (N = 30) and tracheal mucosae (N = 20) were exposed to forskolin, TNFalpha, or vehicle (dimethyl sulfoxide) treatment. cAMP concentrations were determined with enzyme-linked immunosorbent assay. Ion transport was measured using electrophysiological techniques.
  
  
  RESULTS
  Thirty minute exposure to forskolin significantly increased cAMP concentration and ion transport in porcine vocal fold and tracheal mucosae. However, 30-minute and 2-hour exposure to TNFalpha did not significantly alter cAMP concentration.
  
  
  CONCLUSIONS
  We demonstrate that forskolin-sensitive adenylyl cyclase is present in vocal fold mucosa, and further, that the product, cAMP increases vocal fold ion transport. The results presented here contribute to our understanding of the intracellular mechanisms underlying vocal fold ion transport. As ion transport is important for maintaining superficial vocal fold hydration, data demonstrating forskolin-stimulated ion transport in vocal fold mucosa suggest opportunities for developing pharmacological treatments that increase surface hydration.
authors.affiliation: Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, Indiana 47907, USA. msivasankar@purdue.edu
authors.forename: Mahalakshmi
authors.initials: M
authors.lastname: Sivasankar
authors.forename: Charity
authors.initials: C
authors.lastname: Nofziger
authors.forename: Bonnie
authors.initials: B
authors.lastname: Blazer-Yost
mesh_terms: D000818:Animals; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D017136:Ion Transport / Q000187:drug effects / Q000502:physiology*; D007820:Laryngeal Mucosa / Q000378:metabolism*; D008297:Male; D013552:Swine; D014132:Trachea / Q000378:metabolism; D014827:Vocal Cords / Q000502:physiology*
chemical_list: D005576:Colforsin; D000242:Cyclic AMP