Single channel recordings of calcium currents in chick cochlear hair cells.
Single Ca2+ channel currents were recorded from chick cochlear hair cells by using cell-attached patches. The elementary current was about -2 pA at 70 mV positive to the resting potential (R.P.+ 70 mV); the slope conductance over a 40 mV voltage range was 24 pS. The open time histogram was reasonably well expressed by a single exponential function, while the closed time histogram was expressed by a sum of two exponential functions. The Ca2+ channel was activated around R.P.+ 60 mV and the average ensemble current did not decay during 130 ms depolarization, suggesting that the Ca2+ channel in chick cochlear hair cells is the L-type. The Ca2+ channel has three modes of gating behaviour, expressed as current records with brief openings (mode I), no openings (mode 0), or long-lasting openings and very brief closings (mode 2).
Kimitsuki
T
T
Department of Otolaryngology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Nakagawa
T
T
Hisashi
K
K
Komune
S
S
Komiyama
S
S
D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D002645:Chickens; D004553:Electric Conductivity; D004563:Electrochemistry; D006198:Hair Cells, Auditory / Q000502:physiology*; D015640:Ion Channel Gating / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology*
D015220:Calcium Channels