title: Efferent-mediated adaptation of the DPOAE as a predictor of aminoglycoside toxicity.
abstract: Rapid efferent adaptation of the distortion product otoacoustic emission (DPOAE) predicts susceptibility to noise-induced damage, and is linked to the concentration of the efferent receptor (alpha9). Maximum adaptation occurs at intense primary levels, rapidly switching from positive to negative orientation in a very narrow (2 dB) range of F1 and F2 levels. Aminoglycosides are commonly used antibiotics, with the undesirable side-effect of ototoxicity. Susceptibility to hair cell damage from the aminoglycoside gentamicin can be quite variable, even within a single strain and species of animal. Since one of gentamicin's first sites of action in the outer hair cell (OHC) is at the efferent receptor, it is possible that efferent activity could be a predictor of susceptibility to gentamicin induced damage. Significant sex-related differences were found in two strains of guinea pigs when treated with gentamicin. Female guinea pigs were more susceptible both to systemic effects and to specific ototoxic effects. Efferent-mediated DPOAE adaptation served as a predictor of sensitivity to aminoglycoside damage, predicting both number of days before onset of deafness in male animals, and predicting final threshold shifts from gentamicin doses which produced variable results.
authors.affiliation: Department of Otolaryngology, Kresge Hearing Research Institute, 1301 East Ann Street, Ann Arbor, MI 48109-0506, USA.
authors.forename: Karin
authors.initials: K
authors.lastname: Halsey
authors.forename: Asa
authors.initials: A
authors.lastname: Skjönsberg
authors.forename: Mats
authors.initials: M
authors.lastname: Ulfendahl
authors.forename: David F
authors.initials: DF
authors.lastname: Dolan
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D000617:Aminoglycosides / Q000633:toxicity*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D001309:Auditory Threshold / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D005839:Gentamicins / Q000633:toxicity; D006168:Guinea Pigs; D034381:Hearing Loss / Q000139:chemically induced*; D008297:Male; D009476:Neurons, Efferent / Q000187:drug effects*; D017084:Otoacoustic Emissions, Spontaneous / Q000187:drug effects / Q000502:physiology; D012044:Regression Analysis; D012737:Sex Factors; D013047:Specific Pathogen-Free Organisms
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins