Inactivating potassium currents in apical and basal turn inner hair cells from guinea-pig cochlea.
Tetraethylammonium (TEA)-sensitive potassium currents in the cochlear inner hair cells (IHCs) possess the kinetics of fast inactivation. IHCs of guinea-pigs were separately isolated from the apical and basal turns and the tonotopic gradient of inactivation kinetics was investigated. TEA-sensitive potassium currents showed voltage-dependent time constant of the inactivation phase both in apical and basal IHCs, however, the degree of inactivation (compared to the ratio between the steady-state current and initial peak current) was voltage-independent. Inactivation time constant was faster in basal IHCs than in apical IHCs and the degree of inactivation was greater in basal IHCs than in apical IHCs, suggesting that inactivation was more predominant in basal IHCs than in apical IHCs.
Kimitsuki
Takashi
T
Department of Otolaryngology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan. kimitaka@qent.med.kyushu-u.ac.jp
Nawate
Ayako
A
Kakazu
Yasuhiro
Y
Matsumoto
Nozomu
N
Takaiwa
Kazutaka
K
Komune
Noritaka
N
Noda
Teppei
T
Komune
Shizuo
S
D000818:Animals; D003051:Cochlea / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D004553:Electric Conductivity; D004594:Electrophysiology; D006168:Guinea Pigs; D006199:Hair Cells, Auditory, Inner / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000378:metabolism / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D019789:Tetraethylammonium / Q000494:pharmacology
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D019789:Tetraethylammonium