title: Functional and anatomic alterations in the gentamicin-damaged vestibular system in the guinea pig.
abstract: OBJECTIVE
  The purpose of this study was to investigate the expected functional and morphologic effect of gentamicin on the vestibular system simultaneously by measurement of vestibular evoked potentials and electron microscopic evaluation.
  
  
  BACKGROUND
  Vestibular short-latency evoked potentials to linear acceleration have been shown to be a useful parameter of vestibular function. In gentamicin-treated animals, the morphologic damage has been well documented, although this has seldom been quantified.
  
  
  METHODS
  Fifteen guinea pigs were divided into three equal groups. Two groups received different dosages of intramuscular gentamicin for 3 weeks; the third group was the control group. Vestibular short-latency evoked potentials to linear acceleration pulses were measured. After the last gentamicin dose, the utricles were prepared for scanning and transmission electron microscopy. On scanning electron microscopy photographs, the surface area damage ratio of the utricles, a simple method of quantifying gross morphologic damage, was calculated.
  
  
  RESULTS
  The vestibular short-latency evoked potential of gentamicin-treated guinea pigs showed a slow-developing, damaging, dose-response effect on the function of the vestibular system (p = 0.01). Scanning electron microscopy and transmission electron microscopy showed severe morphologic damage in the sensory hair cells of the utricle. The surface area damage ratio showed a dose-response relationship (p = 0.01).
  
  
  CONCLUSIONS
  Functional and anatomic alterations in the gentamicin-damaged vestibular system in the guinea pig are related.
authors.affiliation: Department of Otorhinolaryngology, University Hospital Groningen, Groningen, The Netherlands. m.l.y.m.oei@hccnet.nl
authors.forename: Markus L Y M
authors.initials: ML
authors.lastname: Oei
authors.forename: Hans M
authors.initials: HM
authors.lastname: Segenhout
authors.forename: Freark
authors.initials: F
authors.lastname: Dijk
authors.forename: Ietse
authors.initials: I
authors.lastname: Stokroos
authors.forename: Johannes J L
authors.initials: JJ
authors.lastname: van der Want
authors.forename: Frans W J
authors.initials: FW
authors.lastname: Albers
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D016057:Evoked Potentials, Auditory, Brain Stem / Q000187:drug effects; D005260:Female; D005839:Gentamicins / Q000633:toxicity*; D006168:Guinea Pigs; D018069:Hair Cells, Vestibular / Q000187:drug effects / Q000648:ultrastructure; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D013997:Time Factors; D014722:Vestibule, Labyrinth / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure*
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins