Mechanisms of hair cell tuning.
Mechanosensory hair cells of the vertebrate inner ear contribute to acoustic tuning through feedback processes involving voltage-gated channels in the basolateral membrane and mechanotransduction channels in the apical hair bundle. The specific number and kinetics of calcium-activated (BK) potassium channels determine the resonant frequency of electrically tuned hair cells. Kinetic variation among BK channels may arise through alternative splicing of slo gene mRNA and combination with modulatory beta subunits. The number of transduction channels and their rate of adaptation rise with hair cell response frequency along the cochlea's tonotopic axis. Calcium-dependent feedback onto transduction channels may underlie active hair bundle mechanics. The relative contributions of electrical and mechanical feedback to active tuning of hair cells may vary as a function of sound frequency.
Fettiplace
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Department of Physiology, University of Wisconsin, Madison 53706, USA. fettiplace@physiology.wisc.edu
Fuchs
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PA
D017398:Alternative Splicing; D000818:Animals; D002118:Calcium / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology; D003051:Cochlea / Q000378:metabolism / Q000502:physiology; D004594:Electrophysiology; D014644:Genetic Variation / Q000502:physiology; D006198:Hair Cells, Auditory / Q000502:physiology*; D015640:Ion Channel Gating / Q000502:physiology; D051036:Large-Conductance Calcium-Activated Potassium Channels; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D024681:Potassium Channels, Calcium-Activated
D015220:Calcium Channels; D051036:Large-Conductance Calcium-Activated Potassium Channels; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D002118:Calcium