Modulation of voltage-gated Ca2+ current in vestibular hair cells by nitric oxide
Modulation of voltage-gated Ca2+ current in vestibular hair cells by nitric oxide
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DOI：
10.1152/jn.00849.2006
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发表时间：
2007-02-01
影响因子：
2.5
通讯作者：
Soto, Enrique
中科院分区：
文献类型：
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作者：
Almanza, Angelica;Navarrete, Francisco;Soto, Enrique
一氧化氮-环磷酸鸟苷（NO-cGMP）信号通路的结构元件已在前庭外周系统中被描述。然而，NO在前庭终器中的作用尚不清楚。应用全细胞和穿孔细胞膜片钳技术，观察了NO对大鼠半规管壶腹嵴毛细胞（P14 - P18）Ca ~（2+）电流的作用。NO供体3-吗啉基异壬亚胺（SIN-1）、硝普钠（SNP）和（+/-）-（E）-4-乙基-2-[（Z）-羟基亚氨基]5-硝基-3-己烯-1-基-烟酰胺（NOR- 4）以电压非依赖性方式抑制毛细胞Ca ~（2+）电流。NO清除剂2-（4-羧基苯基）-4，4，5，5-四甲基咪唑啉-1-氧基-3-氧化物（CPTIO）可阻断SNP对Ca 2+电流的抑制作用。鸟苷酸环化酶（sGC）可溶性形式的选择性抑制剂1H-[1，2，4]恶二唑并[4，3- a]喹喔啉1-酮（ODQ）也降低SNP诱导的对Ca 2+电流的抑制。膜渗透性cGMP类似物8-BrcGMP模拟SNP效应。cGMP依赖性蛋白激酶（PGK）的特异性抑制剂KT- 5823可阻断SNP和8-Br-cGMP对Ca 2+电流的抑制作用。在N-乙基马来酰亚胺（NEM），巯基烷基化剂，防止S-亚硝基化反应的存在下，SNP对Ca 2+电流的影响显着减少。这些结果表明，NO通过激活cGMP信号通路和通过S-亚硝基化反应直接作用于通道蛋白，以电压非依赖性方式抑制大鼠前庭毛细胞中电压激活的Ca 2+电流。NO对Ca ~（2+）电流的抑制作用可能与调节细胞内Ca ~（2+）浓度和毛细胞突触传递有关。
The structural elements of the nitric oxide - cyclic guanosine monophosphate ( NO - cGMP) signaling pathway have been described in the vestibular peripheral system. However, the functions of NO in the vestibular endorgans are still not clear. We evaluated the action of NO on the Ca2+ currents in hair cells isolated from the semicircular canal crista ampullaris of the rat (P14 - P18) by using the whole cell and perforated- cell patch- clamp technique. The NO donors 3-morpholinosydnonimine ( SIN-1), sodium nitroprusside ( SNP), and (+/-)-( E)-4- ethyl- 2-[(Z)- hydroxyimino]5- nitro- 3- hexen-1-yl- nicotinamide (NOR- 4) inhibited the Ca2+ current in hair cells in a voltage- independent manner. The NO scavenger 2-(4- carboxyphenyl)- 4,4,5,5- tetramethylimidazoline-1-oxyl- 3-oxide ( CPTIO) prevented the inhibitory effect of SNP on the Ca2+ current. The selective inhibitor of the soluble form of the enzyme guanylate cyclase (sGC), 1H-[ 1,2,4] oxadiazolo[ 4,3- a] quinoxalin1- one (ODQ), also decreased the SNP-induced inhibition of the Ca2+ current. The membrane-permeant cGMP analogue 8-BrcGMP mimicked the SNP effect. KT- 5823, a specific inhibitor of cGMP-dependent protein kinase (PGK), prevented the inhibition of the Ca2+ current by SNP and 8-Br-cGMP. In the presence of N-ethylmaleimide (NEM), a sulfhydryl alkylating agent that prevents the S-nitrosylation reaction, the SNP effect on the Ca2+ current was significantly diminished. These results demonstrated that NO inhibits in a voltage- independent manner the voltage- activated Ca2+ current in rat vestibular hair cells by the activation of a cGMP- signaling pathway and through a direct action on the channel protein by a S-nitrosylation reaction. The inhibition of the Ca2+ current by NO may contribute to the regulation of the intracellular Ca2+ concentration and hair- cell synaptic transmission.