M-like K+ currents in type I hair cells and calyx afferent endings of the developing rat utricle
M-like K+ currents in type I hair cells and calyx afferent endings of the developing rat utricle
复制标题
发育中大鼠外耳道 I 型毛细胞和萼传入末梢的 M 型 K+ 电流
DOI：
10.1523/jneurosci.2596-06.2006
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发表时间：
2006-10-04
影响因子：
5.3
通讯作者：
Eatock, Ruth Anne
中科院分区：
文献类型：
--
作者：
Hurley, Karen M.;Gaboyard, Sophie;Eatock, Ruth Anne
I 型前庭毛细胞具有较大的 K+ 电流，与神经元 M 电流一样，可激活静息电位的负电位并且可调节。在啮齿动物中，这些电流是出生后获得的。在大鼠椭圆囊毛细胞的穿孔贴片记录中，未成熟的毛细胞[小于出生后第 7 天 (P7)] 具有稳态 K+ 电导 (g(-30))，半激活电压 (V-1/ 2) 为 -30 mV。在成熟的 II 型细胞中，大小和激活范围没有变化，但到了 P16，I 型细胞增加了 K 电导，平均增加了四倍，并且激活更加消极。该电导可以包括两个分量：g(-60)（-60mV的V-1/2）和g(-80)（-80mV的V-1/2）。 g(-80) 在破裂的贴片记录期间被冲走，并被蛋白激酶抑制剂阻断。M 电流可以包括来自 KCNQ 和 ether-a-go-go 相关 (erg) 通道的贡献。 KCNQ 和 erg 通道阻滞剂均影响 I 型细胞的 K+ 电流，其中 KCNQ 阻滞剂在小于 P7 时更有效，而 erg 阻滞剂在大于 P16 时更有效。单细胞逆转录-PCR 和免疫细胞化学显示 KCNQ 和 erg 亚基的表达。我们认为 KCNQ 通道有助于 g(-30) 和 g-(60)，而 erg 亚基有助于 g(-80)。I 型毛细胞通过肾盏传入末梢接触。分离的肾盏和传入末梢的记录显示出较大的 K+ 电导，包括 KCNQ 电导。花萼末端被 KCNQ4 和 erg1 抗血清强烈标记。因此，毛细胞和花萼末端都具有类似 M 的大 K+ 电导，具有控制传输增益的潜力。
Type I vestibular hair cells have large K+ currents that, like neuronal M currents, activate negative to resting potential and are modulatable. In rodents, these currents are acquired postnatally. In perforated-patch recordings from rat utricular hair cells, immature hair cells [younger than postnatal day 7 (P7)] had a steady-state K+ conductance (g(-30)) with a half-activation voltage (V-1/ 2) of -30 mV. The size and activation range did not change in maturing type II cells, but, by P16, type I cells had added a K conductance that was on average fourfold larger and activated much more negatively. This conductance may comprise two components: g(-60) (V-1/2 of -60 mV) and g(-80) (V-1/ 2 of -80 mV). g(-80) washed out during ruptured patch recordings and was blocked by a protein kinase inhibitor.M currents can include contributions from KCNQ and ether-a-go-go-related (erg) channels. KCNQ and erg channel blockers both affected the K+ currents of type I cells, with KCNQ blockers being more potent at younger than P7 and erg blockers more potent at older than P16. Single-cell reverse transcription-PCR and immunocytochemistry showed expression of KCNQ and erg subunits. We propose that KCNQ channels contribute to g(-30) and g-(60) and erg subunits contribute to g(-80).Type I hair cells are contacted by calyceal afferent endings. Recordings from dissociated calyces and afferent endings revealed large K+ conductances, including a KCNQ conductance. Calyx endings were strongly labeled by KCNQ4 and erg1 antisera. Thus, both hair cells and calyx endings have large M-like K+ conductances with the potential to control the gain of transmission.