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

J Neurosci. 2014 May 14;34(20):6843-8. doi: 10.1523/JNEUROSCI.4990-13.2014.

Abstract

Sound encoding is mediated by Ca(2+) 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 Ca(2+) current through CaV1.3 channels and Ca(2+) homeostasis in mouse inner hair cells. Patch-clamp recordings and Ca(2+) imaging demonstrate that hydrolyzable ATP is essential to maintain synaptic Ca(2+) influx in inner hair cells via fueling Ca(2+)-ATPases to avoid an increase in cytosolic [Ca(2+)] and subsequent Ca(2+)/calmodulin-dependent inactivation of CaV1.3 channels.

Keywords: calcium; calmodulin; channel; hair cell; inactivation; ribbon synapse.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Animals
  • Calcium / metabolism*
  • Calcium Channels, L-Type / metabolism*
  • Calcium Signaling / physiology
  • Hair Cells, Auditory, Inner / cytology
  • Hair Cells, Auditory, Inner / metabolism*
  • Hydrolysis
  • Ion Transport / physiology
  • Mice
  • Phosphorylation
  • Synapses / metabolism*

Substances

  • Cacna1d protein, mouse
  • Calcium Channels, L-Type
  • Adenosine Triphosphate
  • Calcium