ATP hydrolysis is critically required for function of CaV1.3 channels in cochlear inner hair cells via fueling Ca2+ clearance

Abstract

Sound encoding is mediated by Ca2+ influx-evoked release of glutamate at the ribbon synapse of inner hair cells. Here we studied the role of ATP in this process focusing on Ca2+ current through CaV1.3 channels and Ca2+ homeostasis in mouse inner hair cells. Patch-clamp recordings and Ca2+ imaging demonstrate that hydrolyzable ATP is essential to maintain synaptic Ca2+ influx in inner hair cells via fueling Ca2+-ATPases to avoid an increase in cytosolic [Ca2+] and subsequent Ca2+/calmodulin-dependent inactivation of CaV1.3 channels. ©2014 the authors.