273. Smotherman MS and Narins PM. (1999) The electrical properties of auditory hair cells in the frog amphibian papilla. J Neurosci 19:5275-92.

NeuronCompartmentPropertyConnectivityNotes
Cochlea hair outer cellSomaI K.Using a whole chick (Gallus domesticus) basilar papilla preparation, a map of changes in potassium currents of tall hair cells was produced. All cells recorded from expressed IKCa and IK. The amplitude of total outward current increased in a gradient along the tonotopic axis (Pantelias AA et al, 2001 [chick ]272 ). Whole-cell patch-clamp recordings were used to identify and characterize ionic currents in isolated cells. Most cells possessed a slowly activating IK, which is approximately 80% inactive at rest. In a small subset of cells, IK was replaced by an IA. It is suggested that the kinetic properties of the ionic currents argue against electrical tuning (Smotherman MS and Narins PM, 1999 [frog ]273 ).
Cochlea hair outer cellSomaI K,Ca.The effects of intracellular calcium buffering on electrical tuning were studied in hair cells at apical and basal cochlear locations tuned to 100 and 300 Hz. High conductance KCa channels were 2-fold less Ca2+ sensitive in high-frequency than in low-frequency cells. It is suggested that each KCa channel is gated by Ca2+ entry through a few nearby Ca2+ channels, and that Ca2+ and KCa channels occupy, at constant channel density, a greater fraction of the membrane area in high-frequency cells than in low-frequency cells (Ricci AJ et al, 2000 [turtle ]275 ). Whole-cell and cell-attached patch-clamp recordings showed that ACh activates apamin-sensitive, "SK"-type potassium channels (Yuhas WA and Fuchs PA, 1999 [chick ]276 ). Whole-cell patch-clamp recordings were used to identify and characterize ionic currents in isolated cells. All hair cells possessed an IKCa (Smotherman MS and Narins PM, 1999 [frog ]274 ). Using a whole chick (Gallus domesticus) basilar papilla preparation, a map of changes in potassium currents of tall hair cells was produced. All cells recorded from expressed IKCa and IK. The amplitude of total outward current increased in a gradient along the tonotopic axis (Pantelias AA et al, 2001 [chick ]272 ). Whole-cell patch-clamp recordings showed that variations in the kinetics of the outward current contribute substantially to the determination of resonant frequency (Smotherman MS and Narins PM, 1999 [frog ]273 ).
Cochlea hair inner cellSomaI K.Using a whole chick (Gallus domesticus) basilar papilla preparation, a map of changes in potassium currents of tall hair cells was produced. All cells recorded from expressed IKCa and IK. The amplitude of total outward current increased in a gradient along the tonotopic axis (Pantelias AA et al, 2001 [chick ]272 ). Whole-cell patch-clamp recordings were used to identify and characterize ionic currents in isolated cells. Most cells possessed a slowly activating IK, which is approximately 80% inactive at rest. In a small subset of cells, IK was replaced by an IA. It is suggested that the kinetic properties of the ionic currents argue against electrical tuning (Smotherman MS and Narins PM, 1999 [frog ]273 ).
Cochlea hair inner cellSomaI K,Ca.The effects of intracellular calcium buffering on electrical tuning were studied in hair cells at apical and basal cochlear locations tuned to 100 and 300 Hz. High conductance KCa channels were 2-fold less Ca2+ sensitive in high-frequency than in low-frequency cells. It is suggested that each KCa channel is gated by Ca2+ entry through a few nearby Ca2+ channels, and that Ca2+ and KCa channels occupy, at constant channel density, a greater fraction of the membrane area in high-frequency cells than in low-frequency cells (Ricci AJ et al, 2000 [turtle ]275 ). Whole-cell and cell-attached patch-clamp recordings showed that ACh activates apamin-sensitive, "SK"-type potassium channels (Yuhas WA and Fuchs PA, 1999 [chick ]276 ). Whole-cell patch-clamp recordings were used to identify and characterize ionic currents in isolated cells. All hair cells possessed an IKCa (Smotherman MS and Narins PM, 1999 [frog ]274 ). Using a whole chick (Gallus domesticus) basilar papilla preparation, a map of changes in potassium currents of tall hair cells was produced. All cells recorded from expressed IKCa and IK. The amplitude of total outward current increased in a gradient along the tonotopic axis (Pantelias AA et al, 2001 [chick ]272 ). Whole-cell patch-clamp recordings showed that variations in the kinetics of the outward current contribute substantially to the determination of resonant frequency (Smotherman MS and Narins PM, 1999 [frog ]273 ).

References
272. Pantelias AA, Monsivais P and Rubel EW. (2001) Tonotopic map of potassium currents in chick auditory hair cells using an intact basilar papilla. Hear Res 156:81-94.
273. Smotherman MS and Narins PM. (1999) The electrical properties of auditory hair cells in the frog amphibian papilla. J Neurosci 19:5275-92.
275. Ricci AJ, Gray-Keller M and Fettiplace R. (2000) Tonotopic variations of calcium signalling in turtle auditory hair cells. J Physiol 524 Pt 2:423-36.
276. Yuhas WA and Fuchs PA. (1999) Apamin-sensitive, small-conductance, calcium-activated potassium channels mediate cholinergic inhibition of chick auditory hair cells. J Comp Physiol A 185:455-62.
274. Smotherman MS and Narins PM. (1999) Potassium currents in auditory hair cells of the frog basilar papilla. Hear Res 132:117-30.
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