WHO:	Richard D. Rabbitt, Ph.D. , Professor of Bioengineering, Unversity of Utah, Salt Lake City, UT
TOPIC:	Biophysics of the Inner Ear: From Fluid Mechanics to Molecular Motors
ABSTRACT:	Sensory hair-cell organs of the inner ear are remarkably sensitive and can resolve mechanical motion at a level approaching thermal noise. On the organ level, biomechanical specializations play a central role in determining the sensitivity to a particular mechanical stimulus such as sound (cochlea), linear acceleration (otolith organs) or angular acceleration (semicircular canals). On the cellular level, mechano-transduction is an active process involving two motor proteins -myosin located in the ciliary hair bundles of all sensory hair cells and prestin located in the lateral wall of mammalian outer hair cells. The first part of the presentation will begin with a brief overview of organ-level biomechanics of the inner ear followed by a discussion of recent data on role of myosin-mediated hair bundle motility in angular motion transduction by the semicircular canals. The second part of the presentation will focus on the cochlea with specific attention to outer hair cell somatic electromotility and the role of prestin-mediated electromechanics on mammalian hearing. New micro-domain electric impedance (mEI) data will be presented showing liquid-crystal piezoelectric properties of the outer hair cell lateral wall. The mEI data were collected using novel MEMS developed in our laboratory for single-cell electrophysiological studies. Results further elucidate the role of active electromotile properties of hair cells in enhancing the sensitivity and selectivity of the mammalian cochlea.
WHEN:	1/20/2004 10:00:00 AM
WHERE:	Med Center K307 (3-6408)

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