Olivocochlear suppression of outer hair cells in vivo: evidence for combined action of BK and SK2 channels throughout the cochlea

Stéphane F Maison, Sonja J Pyott, Andrea L Meredith, M Charles Liberman

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33 Citations (Scopus)


Cholinergic inhibition of cochlear hair cells via olivocochlear (OC)-efferent feedback is mediated by Ca(2+) entry through α9-/α10-nicotinic receptors, but the nature of the K(+) channels activated by this Ca(2+) entry has been debated (Yoshida N, Hequembourg SJ, Atencio CA, Rosowski JJ, Liberman MC. J Neurophysiol 85: 84-88, 2001). A recent in vitro study (Wersinger E, McLean WJ, Fuchs PA, Pyott SJ. PLoS One 5: e13836, 2010) suggests that small-conductance (SK2) channels mediate cholinergic effects in the apical turn, whereas large-conductance (BK) channels mediate basal turn effects. Here, we measure, as a function of cochlear frequency, the magnitude of BK and SK2 expression in outer hair cells and the strength of in vivo OC suppression in BK(+/+) mice vs. BK(-/-) lacking the obligatory α-subunit (Meredith AL, Thorneloe KS, Werner ME, Nelson MT, Aldrich RW. J Biol Chem 279: 36746-36752, 2004). Except at the extreme apical tip, we see immunostaining for both BK and SK2 in BK(+/+). Correspondingly, at all testable frequencies (8-45 kHz), we see evidence for both SK2 and BK contributions to OC effects evoked by electrically stimulating the OC bundle: OC-mediated suppression was reduced, but not eliminated, at all frequencies in the BK(-/-) ears. The suppression remaining in BK nulls was blocked by strychnine, suggesting involvement of α9-/α10-cholinergic receptors, coupled to activation of the remaining SK2 channels.

Original languageEnglish
Pages (from-to)1525-34
Number of pages10
JournalJournal of Neurophysiology
Issue number6
Publication statusPublished - 2013
Externally publishedYes


  • Animals
  • Auditory Pathways
  • Cochlea
  • Hair Cells, Auditory, Outer
  • Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
  • Mice
  • Mice, Mutant Strains
  • Small-Conductance Calcium-Activated Potassium Channels
  • Strychnine

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