Property of I(K,)(n) in inner hair cells isolated from guinea-pig cochlea.
One of the potassium currents, I(K,)(n), is already activated at the resting potential of the cell and thus determines the membrane potential. KCNQ4 channel has been identified as the molecular correlate of I(K,)(n). In the present study, we measured I(K,)(n) in acutely isolated IHCs of guinea-pig cochlea using the whole-cell voltage-clamp techniques, and investigated the properties of the currents. I(K,)(n) was 70% activated around the resting potential of -60 mV and deactivated on hyperpolarization. I(K,)(n) was blocked by the KCNQ-channel blockers, linopirdine (100 microM) and XE991 (10 microM), but was insensitive to both I(K,f) blocker, tetraethylammonium (TEA), and I(K,s) blocker, 4-aminopyridine (4-AP). There was no significant difference in the size of I(K,)(n) between the apical and basal turn IHCs.
Kimitsuki
Takashi
T
Department of Otolaryngology, Graduate School of Medical Sciences, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higasi-Ku, Fukuoka 812-8582, Japan. kimitaka@qent.med.kyushu-u.ac.jp
Komune
Noritaka
N
Noda
Teppei
T
Takaiwa
Kazutaka
K
Ohashi
Mitsuru
M
Komune
Shizuo
S
D015761:4-Aminopyridine / Q000494:pharmacology; D000818:Animals; D003051:Cochlea / Q000166:cytology / Q000502:physiology*; D006168:Guinea Pigs / Q000502:physiology*; D006199:Hair Cells, Auditory, Inner / Q000166:cytology / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology; D051656:KCNQ Potassium Channels / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D019789:Tetraethylammonium / Q000494:pharmacology
D007211:Indoles; D051656:KCNQ Potassium Channels; D026902:Potassium Channel Blockers; D011725:Pyridines; D019789:Tetraethylammonium; D015761:4-Aminopyridine; C061017:linopirdine