Document Detail


Osmotically induced pressure difference in the cochlea and its effect on cochlear potentials.
MedLine Citation:
PMID:  8071138     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The electrophysiological effects observed during scala tympani displacements in low-frequency biasing experiments, an increase of the summating potential (SP) together with a decrease of the compound action potential (CAP), correlate well with the effects found in guinea pigs with evoked endolymphatic hydrops. This contributes to the hypothesis that displacement of the basilar membrane underlies the changes found in endolymphatic hydrops. A major difference between both experimental situations is that in low-frequency biasing the basilar membrane is continuously moving, whereas in hydrops the hypothesized displacement would be static. To evaluate the importance of this difference, experiments were performed which attempted to evoke a static displacement of the basilar membrane by perfusing the perilymphatic spaces with perfusates of various osmolalities. Perfusion with hypotonic perfusate (183 mOsm/kg) increased the SP and decreased the CAP (4 kHz stimulation) whereas perfusion with a hypertonic perfusate (397 mOsm/kg) decreased both these potentials. The cochlear microphonics were hardly affected. These data demonstrate that both experimental situations (biasing, i.e. dynamic displacement and osmotic pressure, i.e. static displacement) cause similar changes in the SP and the CAP and the data support the hypothesis that basilar membrane displacement towards scala tympani is an important contributing factor to the electrophysiologic changes in endolymphatic hydrops.
Authors:
S F Klis; G F Smoorenburg
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Hearing research     Volume:  75     ISSN:  0378-5955     ISO Abbreviation:  Hear. Res.     Publication Date:  1994 May 
Date Detail:
Created Date:  1994-09-27     Completed Date:  1994-09-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7900445     Medline TA:  Hear Res     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  114-20     Citation Subset:  IM    
Affiliation:
Department of Otorhinolaryngology, Utrecht University, The Netherlands.
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MeSH Terms
Descriptor/Qualifier:
Acoustic Stimulation
Animals
Basilar Membrane / physiology
Cochlea / physiology*
Electrophysiology
Endolymphatic Hydrops / physiopathology*
Evoked Potentials, Auditory*
Female
Guinea Pigs
Osmotic Pressure

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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