title: Ototoxicity of acetic acid on the guinea pig cochlea.
abstract: BACKGROUND
  To evaluate the ototoxicity of acetic acid solutions.
  
  
  METHODS
  Compound action potentials (CAPs) of the eighth nerve were measured in guinea pigs before and after the application of acetic acid in the middle ear cavity. The pH values of the acetic acid solutions were pH 3.0, 4.0, and 5.0, and the application times were 30 min, 24 h, and 1 week.
  
  
  RESULTS
  Acetic acid solution (pH 3.0, N = 3) for 30 min caused no significant elevation in CAP threshold at 4 kHz, but a significant elevation in the threshold was noted for 8 kHz and clicks. Acetic acid solutions (pH 4.0 N = 6, 5.0 N = 5) for 30 min caused no significant elevation in CAP. Acetic acid solution (pH 4.0) for 24 h (N = 5) caused significant elevations of the CAP threshold for 8 kHz, 4 kHz, and for clicks. Acetic acid (pH 5.0) for 24 h (N = 3) caused a significant elevation of the CAP threshold for 4 kHz, but not for 8 kHz or clicks. Acetic acid (pH 5.0) for 1 week (N = 3) caused a small but significant elevation CAP the threshold for 8 kHz and 4 kHz tone bursts, but no significant change was noted for clicks.
  
  
  CONCLUSIONS
  We found a significant toxic effect of acetic acid in guinea pigs on eighth-nerve compound action potentials when the pH was 5.0 or lower. Clearly, the stronger the acidity, and longer the exposure time, the more the CAP threshold was elevated.
authors.affiliation: Section of Otorhinolaryngology, Department of Medicine, Fukuoka Dental College, 2-15-1 Tamura,Sawara-ku, Fukuoka, 814-0193, Japan. yamano@college.fdcnet.ac.jp.|Department of Otorhinolaryngology, Fukuoka University School of Medicine, Jounan-ku Nanakuma 7-45-1, Fukuoka, 814-0180, Japan. yamano@college.fdcnet.ac.jp.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yamano
authors.affiliation: Department of Otorhinolaryngology, Fukuoka University School of Medicine, Jounan-ku Nanakuma 7-45-1, Fukuoka, 814-0180, Japan. hitomi.higuchi6@gmail.com.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Higuchi
authors.affiliation: Department of Otorhinolaryngology, Fukuoka University School of Medicine, Jounan-ku Nanakuma 7-45-1, Fukuoka, 814-0180, Japan. tnakagawa@fukuoka-u.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakagawa
authors.affiliation: Nishi Fukuoka Hospital, Nishi-ku Ikino-matsubara 3-18-8, Fukuoka, 819-8555, Japan. morizono2004@yahoo.co.jp.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Morizono
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology / Q000633:toxicity*; D000200:Action Potentials / Q000187:drug effects* / Q000502:physiology; D000287:Administration, Topical; D000818:Animals; D001309:Auditory Threshold / Q000187:drug effects; D003051:Cochlea / Q000187:drug effects* / Q000503:physiopathology; D003056:Cochlear Nerve / Q000187:drug effects* / Q000503:physiopathology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D008297:Male; D011897:Random Allocation
chemical_list: D019342:Acetic Acid