TY - JOUR
T1 - Cloning and characterization of SK2 channel from chicken short hair cells
AU - Matthews, T. M.
AU - Duncan, R. K.
AU - Zidanic, M.
AU - Michael, T. H.
AU - Fuchs, P. A.
N1 - Funding Information:
Acknowledgements This work was supported by an NIDCD DC01508, Research Core Grants P30 DC05211 and P30 DCO5188, Training Grant T 32 DC00023 and funding from The Whitaker Foundation. These experiments comply with the ‘‘Principles of animal care,’’ publication No. 86–23, revised in 1985, of the National Institute of Health.
PY - 2005/6
Y1 - 2005/6
N2 - 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.
AB - 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.
KW - Chicken
KW - Efferent inhibition
KW - Hair cells
KW - Patch-clamp techniques
KW - Small-conductance calcium-sensitive potassium channels
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U2 - 10.1007/s00359-005-0601-4
DO - 10.1007/s00359-005-0601-4
M3 - Article
C2 - 15868189
AN - SCOPUS:21344437748
SN - 0340-7594
VL - 191
SP - 491
EP - 503
JO - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
JF - Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
IS - 6
ER -