Document Detail


Perilymph osmolality modulates cochlear function.
MedLine Citation:
PMID:  18607303     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES/HYPOTHESIS: The cochlear amplifier is required for the exquisite sensitivity of mammalian hearing. Outer hair cells underlie the cochlear amplifier and they are unique in that they maintain an intracellular turgor pressure. Changing the turgor pressure of an isolated outer hair cells through osmotic challenge modulates its ability to produce electromotile force. We sought to determine the effect of osmotic challenge on cochlear function.
STUDY DESIGN: In vivo animal study.
METHODS: Hypotonic and hypertonic artificial perilymph was perfused through the scala tympani of anesthetized guinea pigs. Cochlear function was assessed by measuring the compound action potential, distortion product otoacoustic emissions, the cochlear microphonic, and the endocochlear potential.
RESULTS: Hypotonic perilymph decreased and hypertonic perilymph increased compound action potential and distortion product otoacoustic emission thresholds in a dose-dependent and reversible manner. The cochlear microphonic quadratic distortion product magnitude increased after hypotonic perfusion and decreased with hypertonic perfusion. There were no changes in the stimulus intensity growth curve of the low-frequency cochlear microphonic. The endocochlear potential was not affected by perilymph osmolality.
CONCLUSIONS: These data demonstrate that perilymph osmolality can modulate cochlear function and are consistent with what would be expected if outer hair cells turgor pressure changes the gain of the cochlear amplifier in vivo.
Authors:
Chul-Hee Choi; John S Oghalai
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Laryngoscope     Volume:  118     ISSN:  1531-4995     ISO Abbreviation:  Laryngoscope     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-09-03     Completed Date:  2008-09-16     Revised Date:  2013-04-16    
Medline Journal Info:
Nlm Unique ID:  8607378     Medline TA:  Laryngoscope     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1621-9     Citation Subset:  IM    
Affiliation:
The Bobby R. Alford Department of Otolaryngology-Head and Neck Surgery, Baylor College of Medicine, Houston, Texas 77030, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Audiometry, Evoked Response
Cochlea / physiology*
Cochlear Microphonic Potentials
Female
Guinea Pigs
Male
Osmolar Concentration
Otoacoustic Emissions, Spontaneous
Perfusion
Perilymph / physiology*
Grant Support
ID/Acronym/Agency:
DC006671/DC/NIDCD NIH HHS; DC05131/DC/NIDCD NIH HHS; K08 DC006671/DC/NIDCD NIH HHS; R03 DC005131/DC/NIDCD NIH HHS
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