Monitoring transient Ca2+ dynamics with BK channels at active zones in frog saccular hair cells

Neurotransmitter release from the basolateral surface of auditory and vestibular hair cells is mediated by Ca 2+ influx through voltage-gated Ca 2+ channels. Co-localization of large-conductance Ca 2+ -activated K + (BK) channels at the active zones of these cells affords them with an optimal locati...

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Bibliographic Details
Published in:Neuroscience 2009-11, Vol.165 (3), p.715
Main Authors: Sy, Thanh, Grinnell, Alan D., Peskoff, Arthur, Yazejian, Bruce
Format: Article
Language:English
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Summary:Neurotransmitter release from the basolateral surface of auditory and vestibular hair cells is mediated by Ca 2+ influx through voltage-gated Ca 2+ channels. Co-localization of large-conductance Ca 2+ -activated K + (BK) channels at the active zones of these cells affords them with an optimal location to act as reporters of the Ca 2+ concentration changes at active zones of transmitter release. In this report we use BK channels to monitor dynamic changes in intracellular Ca 2+ concentration during transient influxes of Ca 2+ , showing that BK current magnitude and delay to onset are correlated with the rate and duration of Ca 2+ entry through Ca 2+ channels. We also show that BK channels exhibit a much higher Ca 2+ binding affinity in the open state than in the closed state.
ISSN:0306-4522
1873-7544
DOI:10.1016/j.neuroscience.2009.11.003