Mechanical AJ Hudspeth amplification of stimuli by hair cells
نویسنده
چکیده
Unlike any other known sensory receptor, the hair cell uses positive feedback to augment the stimulus to which it responds. In the internal ears of many vertebrates, hair cells amplify the inputs to their mechanosensitive hair bundles. Outer hair cells of the mammalian cochlea display a unique form of somatal motility that may underlie their contribution to amplification. In other receptor organs, hair cells may effect amplification by hair-bundle movements driven by the activity of myosin or of transduction channels. Recent work has demonstrated the presence of several myosin isozymes in hair bundles, confirmed that bundles display myosin ATPase activity, and shown that the work performed by myosin molecules could account for one aspect of the amplificatory process.
منابع مشابه
Negative hair-bundle stiffness betrays a mechanism for mechanical amplification by the hair cell.
Hearing and balance rely on the ability of hair cells in the inner ear to sense miniscule mechanical stimuli. In each cell, sound or acceleration deflects the mechanosensitive hair bundle, a tuft of rigid stereocilia protruding from the cell's apical surface. By altering the tension in gating springs linked to mechanically sensitive transduction channels, this deflection changes the channels' o...
متن کاملActive hair-bundle movements can amplify a hair cell's response to oscillatory mechanical stimuli.
To enhance their mechanical sensitivity and frequency selectivity, hair cells amplify the mechanical stimuli to which they respond. Although cell-body contractions of outer hair cells are thought to mediate the active process in the mammalian cochlea, vertebrates without outer hair cells display highly sensitive, sharply tuned hearing and spontaneous otoacoustic emissions. In these animals the ...
متن کاملWhat drives mechanical amplification in the mammalian cochlea?
The recent report by Peter Dallos and colleagues of the gene and protein responsible for outer hair cell somatic motility (Zheng, Shen, He, Long, Madison, & Dallos, 2000), and the work of James Hudspeth and colleagues demonstrating that vestibular stereocilia are capable of providing power that may boost the vibration of structures within the inner ear (Martin & Hudspeth, 1999), presents the ta...
متن کاملThe cellular basis of hearing: the biophysics of hair cells.
A crucial event in the hearing process is the transduction of mechanical stimuli into electrical signals by hair cells, the sensory receptors of the internal ear. Stimulation results in the rapid opening of ionic channels in the mechanically sensitive organelles of these cells, their hair bundles. These transduction channels, which are nonselectively permeable, are directly excited by hair-bund...
متن کاملResponse latency of vertebrate hair cells.
An in vitro preparation of hair cells from the bullfrog sacculus produces a transepithelial microphonic potential in response to well-defined mechanical stimuli. If corrected for the electrical time constant of the epithelium, the response follows a fast stimulus with a 40-microsecond delay at 22 degree C. The short latency and its modest temperature dependence limit possible models for transdu...
متن کامل