The ionic channels of a vertebrate hair cell.
The ionic channels of hair cells play important roles in mechanoelectrical transduction, frequency tuning, and synaptic transmission. In the hair cells of the bullfrog's sacculus, transduction is mediated by mechanically gated, poorly selective channels located in the hair bundle. Statistical analysis of the variance in the transduction current measured under voltage-clamp conditions indicates that a cell has only a few hundred transduction channels, each with a conductance of approximately 17 pS at room temperature. The same cells employ a resonance in their membrane potential to enhance their frequency selectivity in responses to mechanical stimuli. Voltage-clamp studies indicate that the resonance results principally from the interplay of two ionic conductances, a voltage-sensitive Ca2+ conductance and a Ca2+-sensitive K+ conductance.
D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002118:Calcium / Q000378:metabolism*; D007473:Ion Channels / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D008564:Membrane Potentials; D008959:Models, Neurological; D009431:Neural Conduction; D011188:Potassium / Q000378:metabolism*; D011892:Rana catesbeiana; D012444:Saccule and Utricle / Q000294:innervation*
D007473:Ion Channels; D011188:Potassium; D002118:Calcium