豚鼠耳蜗内毛细胞中 I(K,)(n) 的特性。

Property of I(K,)(n) in inner hair cells isolated from guinea-pig cochlea.

机构信息

Department of Otolaryngology, Graduate School of Medical Sciences, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higasi-Ku, Fukuoka 812-8582, Japan.

出版信息

Hear Res. 2010 Mar;261(1-2):57-62. doi: 10.1016/j.heares.2010.01.002. Epub 2010 Jan 12.

DOI:10.1016/j.heares.2010.01.002

PMID:20060884

Abstract

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.

摘要

一种钾电流，I(K,)(n)，在细胞的静息电位下已经被激活，因此决定了膜电位。KCNQ4 通道已被确定为 I(K,)(n)的分子相关物。在本研究中，我们使用全细胞膜片钳技术测量了豚鼠耳蜗急性分离的 IHC 中的 I(K,)(n)，并研究了电流的特性。I(K,)(n)在 -60 mV 的静息电位附近被激活 70%，在超极化时失活。I(K,)(n)被 KCNQ 通道阻滞剂林匹啶（100 μM）和 XE991（10 μM）阻断，但对 I(K,f)阻滞剂四乙铵（TEA）和 I(K,s)阻滞剂 4-氨基吡啶（4-AP）均不敏感。顶回和底回 IHC 之间的 I(K,)(n)大小没有显著差异。