ATP Hydrolysis Is Critically Required for Function of CaV1.3 Channels in Cochlear Inner Hair Cells via Fueling Ca2+ Clearance

摘要

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.