Elevation of intracellular calcium induced by the intrapipette perfusion technique modifies membrane ion currents in the chick cochlear hair cell.
The concentration of intracellular calcium ion ([Ca2+]i) was altered in the same hair cell dissociated from a chick cochlea by the intrapipette perfusion technique. At a membrane potential of -40 mV, the elevation of [Ca2+]i generated outward-going currents within 60 sec when the intrapipette solution was based on KCl. In controls, at membrane potentials more positive than -50 mV, outward K+ currents were observed and at large positive potentials, the outward K+ current decreased, showing an N-shaped I-V relationship. This outward K+ current was increased by elevation of [Ca2+]i and was partially suppressed by a TEA-containing extracellular solution. We suggest that the Ca2+ increased by the intrapipette perfusion technique operates directly inside the cell membrane and activates Ca(2+)-activated K+ currents.
Kimitsuki
T
T
Department of Otorhinolaryngology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Nakagawa
T
T
Hisashi
K
K
Tsuji
K
K
Komune
S
S
Komiyama
S
S
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology*; D002478:Cells, Cultured; D002645:Chickens; D006198:Hair Cells, Auditory / Q000502:physiology*; D007424:Intracellular Fluid / Q000378:metabolism*; D008564:Membrane Potentials / Q000502:physiology; D010477:Perfusion; D015221:Potassium Channels / Q000502:physiology
D015220:Calcium Channels; D015221:Potassium Channels; D002118:Calcium