gms | German Medical Science

93rd Annual Meeting of the Southwest German Association of Otorhinolaryngologists

17. - 19.09.2009, Neu-Ulm

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The influence of cholesterol on the motility of cochlear outer hair cells and the motor protein prestin

Der Einfluss von Cholesterin auf die Motilität äußerer cochleärer Haarzellen und das Motorprotein Prestin

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  • corresponding author presenting/speaker Martin Canis - Universität München, München, Germany
  • Johannes Schmidt - Universität München, München, Germany
  • Michael Strupp - Universität München, München, Germany
  • Klaus Jahn - Universität München, München, Germany
  • Markus Suckfüll - Universität München, München, Germany

Vereinigung Südwestdeutscher Hals-Nasen-Ohrenärzte. 93. Jahrestagung der Vereinigung Südwestdeutscher Hals-Nasen-Ohrenärzte. Neu-Ulm, 17.-19.09.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09hnosw07

doi: 10.3205/09hnosw07, urn:nbn:de:0183-09hnosw070

Published: September 10, 2009

© 2009 Canis et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objectives: Elevated serum cholesterol is linked to inner ear disorders and may influence hearing by altering membrane properties of outer hair cells (OHC) and by affecting the motor protein prestin. In this study we wanted to answer the question, if cholesterol modulates electromotility of OHCs and if this modulation results from effects on the membrane properties or on the motor protein prestin.

Method: The motile responses of 12 isolated OHCs were investigated at increasing concentrations of 0, 0.1 and 1 mM extracellular cholesterol using the patch clamp technique and continuous video image analysis. To study effects on prestin, experiments were performed at 12 cells with half activated protein function and concentrations of 0 and 1 mM cholesterol.

Results: Cholesterol at a concentration of 0.1 mM had no effects on motility. 1 mM reduced maximal evoked shortening significantly by 29% in the depolarizing and by 9% in the hyperpolarizing direction. Investigating half activated motor proteins, 1 mM cholesterol reduced movements significantly by 18%, elongations decreased not significantly by 5%.

Conclusions: We provide evidence that cholesterol reduces electromotility in a dose-dependent matter. The data show that cholesterol modulates electromotility mainly by influencing the motor protein prestin, less by affecting the passive membrane properties.