Frequency of damped oscillations in cochlear hair cell membrane potential

Range 20 - 320 Hz
Organism Turtle Trachemys scripta elegans
Reference Crawford AC, Fettiplace R. The mechanical properties of ciliary bundles of turtle cochlear hair cells. J Physiol. 1985 Jul364: 359-79. p.359 heading '5' & p.368 top paragraphPubMed ID4032304
Method "The object of the work to be described is a quantitative analysis of the mechanical properties of the hair bundles. The approach has been to measure the bending of a single bundle in the turtle cochlea by attaching it to a flexible glass fibre, and monitoring the fibre's motion through its shadowing of a light beam falling on a photodiode array."
Comments "Step displacements of the fixed end of the flexible fibre caused the hair cell's membrane potential to execute damped oscillations: the frequency of the oscillations in different cells ranged from 20 to 320 Hz. Displacements towards the kinocilium [="a special type of cilium on the apex of hair cells located in the sensory epithelium of the vertebrate inner ear.", wiki] always produced membrane depolarization...Fig. 6 illustrates receptor potentials from four different cells: for each, the step response consisted of a damped oscillation at the onset and termination of the step, and the resonant frequency, given beside the traces, was different between cells. The results suggest that individual hair cells retain much of their frequency selectivity in this isolated papillar preparation. Resonant frequencies from 20 to 320 Hz were observed in these experiments. They cover part of the range of resonant frequencies seen in the intact cochlea using sound stimulation, although there was a notable absence of higher frequency cells, which normally extend up to about 600 Hz."
Entered by Uri M
ID 111035