The Coupling between Ca²⁺ Channels and the Exocytotic Ca²⁺ Sensor at Hair Cell Ribbon Synapses Varies Tonotopically along the Mature Cochlea.

ABSTRACT: The cochlea processes auditory signals over a wide range of frequencies and intensities. However, the transfer characteristics at hair cell ribbon synapses are still poorly understood at different frequency locations along the cochlea. Using recordings from mature gerbils, we report here a surprisingly strong block of exocytosis by the slow Ca²⁺ buffer EGTA (10 mM) in basal hair cells tuned to high frequencies (∼30 kHz). In addition, using recordings from gerbil, mouse, and bullfrog auditory organs, we find that the spatial coupling between Ca²⁺ influx and exocytosis changes from nanodomain in low-frequency tuned hair cells (∼<2 kHz) to progressively more microdomain in high-frequency cells (∼>2 kHz). Hair cell synapses have thus developed remarkable frequency-depende

SUBMITTER: Johnson SL 

PROVIDER: S-EPMC5354352 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature