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Proceedings Paper

Effect of salicylate on outer hair cell plasma membrane viscoelasticity: studies using optical tweezers
Author(s): Sergey A. Ermilov; William E. Brownell; Bahman Anvari
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Paper Abstract

The plasma membrane (PM) of mammalian outer hair cells (OHCs) generates mechanical forces in response to changes in the transmembrane electrical potential. The resulting change in the cell length is known as electromotility. Salicylate (Sal), the anionic, amphipathic derivative of aspirin induces reversible hearing loss and decreases electromotile response of the OHCs. Sal may change the local curvature and mechanical properties of the PM, eventually resulting in reduced electromotility or it may compete with intracellular monovalent anions, particularly Cl-, which are essential for electromotility. In this work we have used optical tweezers to study the effects of Sal on viscoelastic properties of the OHC PM when separated from the underlying composite structures of the cell wall. In this procedure, an optically trapped microsphere is brought in contact with PM and subsequently pulled away to form a tether. We measured the force exerted on the tether as a function of time during the process of tether growth at different pulling rates. Effective tether viscosity, steady-state tethering force extrapolated to zero pulling rate, and the time constant for tether growth were estimated from the measurements of the instantaneous tethering force. The time constant for the tether growth measured for the OHC basal end decreased 1.65 times after addition of 10 mM Sal, which may result from an interaction between Sal and cholesterol, which is more prevalent in the PM of OHC basal end. The time constants for the tether growth calculated for the OHC lateral wall and control human embryonic kidney cells as well as the other calculated viscoelastic parameters remained the same after Sal perfusion, favoring the hypothesis of competitive inhibition of electromotility by salicylate.

Paper Details

Date Published: 1 June 2004
PDF: 7 pages
Proc. SPIE 5331, Nanobiophotonics and Biomedical Applications, (1 June 2004); doi: 10.1117/12.529200
Show Author Affiliations
Sergey A. Ermilov, Rice Univ. (United States)
William E. Brownell, Baylor College of Medicine (United States)
Bahman Anvari, Rice Univ. (United States)

Published in SPIE Proceedings Vol. 5331:
Nanobiophotonics and Biomedical Applications
Alexander N. Cartwright, Editor(s)

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