Voltage-dependent outer hair cell stereocilia stiffness at acoustic frequencies.

The aim of this report is to show the effects of voltage changes on stereocilia stiffness in mammalian outer hair cells (OHCs). With the OHC cuticular plate anchored at a microchamber tip, step voltage commands drove an OHC inside the microchamber to move freely while stereocilia were oscillated at 510 Hz by a constant fluid-jet force. With basolateral OHC depolarized and shortened, the amplitude of stereocilia motion was increased, suggesting a decrease in stereocilia stiffness. Such a decrease in stiffness may serve as an important adjusting factor inside the cochlear amplifying loop.