Sodium and potassium currents of type I spiral ganglion cells from rat.
Ion channel activity of acutely dissociated type I spiral ganglion cells isolated from rats was investigated using the whole-cell variation of the patch clamp technique. Tetrodotoxin-sensitive sodium current and tetraethylammonium-sensitive potassium current were recorded. With a holding potential of -80 mV, peak sodium currents were generated by depolarizations to membrane potentials more positive than -50 mV. Potassium currents were elicited at membrane potentials more positive than -40 mV. Some cells which did not exhibit sodium current exhibited delayed rectifier potassium currents. Steady-state sodium channel inactivation curve yielded a slope of 12 mV and a half-inactivated potential of -83 mV. Recovery from inactivation of the sodium channel proceeded with a fast and slow time course; recovery began as early as 0.8 ms and proceeded with a time constant of 7.5 ms. It is concluded that type I spiral ganglion cells are endowed with sodium and potassium channels which are responsible for generation and propagation of auditory nerve action potentials.
Moore
E J
EJ
Department of Audiology and Speech Sciences, Michigan State University, East Lansing 48824-1212, USA.
Hall
D B
DB
Narahashi
T
T
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002478:Cells, Cultured; D004594:Electrophysiology; D015640:Ion Channel Gating / Q000502:physiology; D017136:Ion Transport / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D018408:Patch-Clamp Techniques; D011188:Potassium / Q000378:metabolism*; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism*; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000378:metabolism; D013136:Spiral Ganglion / Q000378:metabolism*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds; D013779:Tetrodotoxin
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D013757:Tetraethylammonium Compounds; D013779:Tetrodotoxin; D019789:Tetraethylammonium; D012964:Sodium; D011188:Potassium