Fast adaptation of mechanoelectrical transducer channels in mammalian cochlear hair cells.
Outer hair cells are centrally involved in the amplification and frequency tuning of the mammalian cochlea, but evidence about their transducing properties in animals with fully developed hearing is lacking. Here we describe measurements of mechanoelectrical transducer currents in outer hair cells of rats between postnatal days 5 and 18, before and after the onset of hearing. Deflection of hair bundles using a new rapid piezoelectric stimulator evoked transducer currents with ultra-fast activation and adaptation kinetics. Fast adaptation resembled the same process in turtle hair cells, where it is regulated by changes in stereociliary calcium. It is argued that sub-millisecond transducer adaptation can operate in outer hair cells under the ionic, driving force and temperature conditions that prevail in the intact mammalian cochlea.
Kennedy
Helen J
HJ
Department of Physiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, UK.
Evans
Michael G
MG
Crawford
Andrew C
AC
Fettiplace
Robert
R
D000222:Adaptation, Physiological; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D016922:Cellular Senescence; D004594:Electrophysiology; D006198:Hair Cells, Auditory / Q000502:physiology*; D007473:Ion Channels / Q000502:physiology*; D008465:Mechanoreceptors / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D007473:Ion Channels; D002118:Calcium