Anion efflux mediates transduction in hair cells of zebrafish lateral line

Hair cells are the principal sensory receptors of the vertebrate auditory system, and transduce sounds with mechanically-gated ion channels that permit cations to flow from the surrounding endolymph into the cells. The lateral line of zebrafish has served as a key model system for understanding hair cell physiology and development, and it has often been speculated that these hair cells employ a similar transduction mechanism. In this study, we demonstrate that the hair cells are exposed to an unregulated external environment with cation concentrations that are too low to support transduction. Instead, our results indicate that hair cell excitation is mediated by a fundamentally different mechanism involving the outward flow of anions.