title: Function of the eustachian tube after weekly exposure to pepsin/hydrochloric acid.
abstract: OBJECTIVE
  To determine the effects of repeated pepsin/hydrochloric acid (HCl) exposure on the eustachian tube (ET).
  
  
  METHODS
  ET function was studied in 22 rats. Group I (control) rats received transtympanic phosphate buffered saline solution; groups II (0.5 mg/ml) and III (2.0 mg/ml) received transtympanic pepsin/HCl. Test solutions were applied on day 0 with ET function evaluated on days 1, 2, 3, and 7 after exposure. Each 7-day period represents 1 cycle; all groups underwent 4 cycles. ET function was evaluated using passive opening and closing pressure, and active clearance of positive and negative pressure tests.
  
  
  RESULTS
  Rats exposed to pepsin/HCl had elevated passive opening pressures and a decreased ability to clear positive and negative pressure. A temporal relationship exists.
  
  
  CONCLUSIONS
  The results suggest middle ear exposure to pepsin/HCl leads to ET dysfunction in rats, and that this dysfunction is enhanced with repeated exposures.
  
  
  CONCLUSIONS
  Gastroesophageal reflux may induce ET dysfunction.
authors.affiliation: Department of Surgery, Division of Otolaryngology, Head and Neck Surgery, The University of North Carolina School of Medicine, The University of North Carolina Hospitals, Chapel Hill, USA.
authors.forename: S B
authors.initials: SB
authors.lastname: Heavner
authors.forename: S M
authors.initials: SM
authors.lastname: Hardy
authors.forename: D R
authors.initials: DR
authors.lastname: White
authors.forename: C T
authors.initials: CT
authors.lastname: McQueen
authors.forename: J
authors.initials: J
authors.lastname: Prazma
authors.forename: H C
authors.initials: HC
authors.lastname: Pillsbury
mesh_terms: D000818:Animals; D005064:Eustachian Tube / Q000187:drug effects* / Q000502:physiology*; D005764:Gastroesophageal Reflux / Q000150:complications; D005765:Gastrointestinal Agents / Q000009:adverse effects*; D006851:Hydrochloric Acid / Q000009:adverse effects*; D023421:Models, Animal; D010034:Otitis Media with Effusion / Q000209:etiology; D010434:Pepsin A / Q000009:adverse effects*; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D005765:Gastrointestinal Agents; D010434:Pepsin A; D006851:Hydrochloric Acid