Cloning and characterization of SK2 channel from chicken short hair cells

T. M. Matthews, R. K. Duncan, M. Zidanic, T. H. Michael, P. A. Fuchs

Research output: Contribution to journalArticle

Abstract

In the inner ear of birds, as in mammals, reptiles and amphibians, acetylcholine released from efferent neurons inhibits hair cells via activation of an apamin-sensitive, calcium-dependent potassium current. The particular potassium channel involved in avian hair cell inhibition is unknown. In this study, we cloned a small-conductance, calcium-sensitive potassium channel (gSK2) from a chicken cochlear library. Using RT-PCR, we demonstrated the presence of gSK2 mRNA in cochlear hair cells. Electrophysiological studies on transfected HEK293 cells showed that gSK2 channels have a conductance of approximately 16 pS and a half-maximal calcium activation concentration of 0.74±0.17 μM. The expressed channels were blocked by apamin (IC50=73.3±5.0 pM) and d-tubocurarine (IC50=7.6±1.0 μM), but were insensitive to charybdotoxin. These characteristics are consistent with those reported for acetylcholine-induced potassium currents of isolated chicken hair cells, suggesting that gSK2 is involved in efferent inhibition of chicken inner ear. These findings imply that the molecular mechanisms of inhibition are conserved in hair cells of all vertebrates.

Original languageEnglish (US)
Pages (from-to)491-503
Number of pages13
JournalJournal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
Volume191
Issue number6
DOIs
StatePublished - Jun 1 2005

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Keywords

  • Chicken
  • Efferent inhibition
  • Hair cells
  • Patch-clamp techniques
  • Small-conductance calcium-sensitive potassium channels

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Physiology
  • Animal Science and Zoology
  • Behavioral Neuroscience

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