Document Detail


Effectiveness, active energy produced by molecular motors, and nonlinear capacitance of the cochlear outer hair cell.
MedLine Citation:
PMID:  16060346     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cochlear outer hair cells are crucial for active hearing. These cells have a unique form of motility, named electromotility, whose main features are the cell's length changes, active force production, and nonlinear capacitance. The molecular motor, prestin, that drives outer hair cell electromotility has recently been identified. We reveal relationships between the active energy produced by the outer hair cell molecular motors, motor effectiveness, and the capacitive properties of the cell membrane. We quantitatively characterize these relationships by introducing three characteristics: effective capacitance, zero-strain capacitance, and zero-resultant capacitance. We show that zero-strain capacitance is smaller than zero-resultant capacitance, and that the effective capacitance is between the two. It was also found that the differences between the introduced capacitive characteristics can be expressed in terms of the active energy produced by the cell's molecular motors. The effectiveness of the cell and its molecular motors is introduced as the ratio of the motors'active energy to the energy of the externally applied electric field. It is shown that the effectiveness is proportional to the difference between zero-strain and zero-resultant capacitance. We analyze the cell and motor's effectiveness within a broad range of cellular parameters and estimate it to be within a range of 12%-30%.
Authors:
Alexander A Spector
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of biomechanical engineering     Volume:  127     ISSN:  0148-0731     ISO Abbreviation:  J Biomech Eng     Publication Date:  2005 Jun 
Date Detail:
Created Date:  2005-08-02     Completed Date:  2005-09-27     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7909584     Medline TA:  J Biomech Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  391-9     Citation Subset:  IM    
Affiliation:
Department of Biomedical Engineering, Johns Hopkins University, 720 Rutland avenue, Traylor 411, Baltimore, Maryland 21205, USA. aspector@bme.jhu.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Computer Simulation
Elasticity
Electric Capacitance
Energy Transfer / physiology*,  radiation effects
Hair Cells, Auditory, Outer / physiology*,  radiation effects
Humans
Mechanotransduction, Cellular / physiology*,  radiation effects
Membrane Potentials / physiology*,  radiation effects
Models, Biological*
Molecular Motor Proteins / physiology*,  radiation effects
Movement / physiology,  radiation effects
Nonlinear Dynamics
Chemical
Reg. No./Substance:
0/Molecular Motor Proteins

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


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