ATP Hydrolysis Is Critically Required for Function of Ca(V)1.3 Channels in Cochlear Inner Hair Cells via Fueling Ca2+ Clearance

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 Ca(V)1.3 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 Ca(V)1.3 channels.