Inactivating and non-inactivating potassium currents in isolated inner hair cells from guinea pig cochlea.
Using conventional whole-cell voltage-clamp recordings, we examined the 4-aminopyridine (4-AP)- and tetraethylammonium (TEA)-sensitive K(+) currents in the cochlear inner hair cells (IHCs) of guinea pigs. 4-AP-sensitive currents were activated slowly and sustained the same current level, whereas TEA-sensitive currents were activated rapidly, followed by inactivation. The inactivation time course of TEA-sensitive currents was voltage-dependent, becoming faster at more depolarized levels. The inactivation of TEA-sensitive currents almost recovered within 5 ms. 4-AP- and TEA-sensitive K(+) currents coexisted in the same IHC.
Department of Otorhinolaryngology, Miyazaki Medical College, Kiyotake, Japan. kimituki@fc.miyazaki-med.ac.jp
Takashi
T
Kimitsuki
Mitsuru
M
Ohashi
Yuki
Y
Wada
Shinji
S
Fukudome
Shizuo
S
Komune
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D004553:Electric Conductivity; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006168:Guinea Pigs; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D019789:Tetraethylammonium / Q000494:pharmacology
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D019789:Tetraethylammonium; D015761:4-Aminopyridine