Cells whisper

Cells respond within a millisecond to changes in membrane voltage, emitting sounds whilst they fulfil their function.

Tudor Toma(

Highly specialized cells such as the cochlear outer hair cells responsible for hearing, exhibit cell membrane movement in response to a change in membrane voltage. In September 27 Nature, Ping-Cheng Zhang and colleagues from State University of New York at Buffalo show that less specialized cells, such as human embryonic kidney cells (HEK293), also react in less than a millisecond to changes in membrane voltage (Nature 2001, 413:428-432).

Zhang et al. used an atomic force microscope (AFM), to measure in real time the cellular movements of voltage-clamped HEK293 cells in different ionic-strength solutions. They found that in normal saline, depolarization caused an outward movement, while a low ionic strength caused an inward movement proportional to changes in membrane voltage (about 1 nm per 100 mV). In addition, salicylate — which inhibits cell motility by binding to the 'motor protein' prestin in cochlear cells — substantially reduces...

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