Molecular analysis of the neuropathic pain state using sns-null mutant mice

使用 sns 无效突变小鼠对神经病理性疼痛状态进行分子分析

基本信息

批准号：
13470313
负责人：
FUJIMOTO Yoshinori
金额：
$ 7.55万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13470313/
关键词：
sodium channel dorsal root ganglion tetrodotoxin channel conductance voltage-clamp patch-clamp

项目摘要

Sensory neurons in dorsal root ganglia (DRG) express at least seven isoforms of voltage-gated sodium channel (VGSC) α-subunits. These isoforms show localized distribution within the primary sensory path-way and probably mediate multiple types of sodium currents (I_<Na>) with different kinetic properties, giving rise to fast, slow or persistent I_<Na>s. However, little is known as to which isoform is responsible for a particular I_<Na> in DRG neurons. We have recently identified two types persistent I_<Na>s : one is resistant to tetrodotoxin (TTX) and found exclusively in small DRG neurons (I_<TTX-R/persist>), and the otner is sensitive to TTX and found in medium/large DRG neurons (I_<TTX-S/persist>). Available data suggest that the former is most likely to be mediated by Na_V1.9, while the latter may be mediated by Na_V1.6. To confirm these possibilities, we performed single cell nested RT-PCR combined with concurrent patch clamp recording and investigated the correlation between mRNA … More expression and phenotype of I_<Na> in an identified DRG neuron. I_<TTX-R/persist> was recorded in isolation from small DRG neurons of Na_V1.8-null mutant mice in the presence of TTX. Most of the small neurons, which were associated with Na_V1.9 transcript, manifested I_<TTX-R/persist>, confirming that the isoform mediating I_<TTX-R/persist> is probably Na_V1.9. Unexpectedly, however, Na_V1.9 was evident also in a considerable number of medium/large neurons that were totally devoid of I_<TTX-R/persist>. These results indicate that I_<TTX-R/persist> is not solely dependent on the level of Na_V1.9 transcript. An intriguing finding was that Na_V1.9 transcript was often absent in small DRG neurons from naive mice while the same transcript was evident in most of the small DRG neurons from mutants. Expression of Na_V1.6 transcript was demonstrated in a considerable portion of the medium/large neurons from both naive and mutant mice. However, these neurons did not consistently manifest I_<TTX-S/persist> suggesting that I_<TTX-S/persist> may not be carried by Na_V1.6. Less

背根神经节 (DRG) 中的感觉神经元表达至少七种电压门控钠通道 (VGSC) α 亚基同工型，这些同工型在主要感觉通路中显示局部分布，并可能介导多种类型的钠电流 (I_<)。 Na>）具有不同的动力学特性，产生快速、缓慢或持久的 I_<Na>。然而，对于哪种亚型负责特定的 I_<Na> 却知之甚少。我们最近发现了两种类型的持久性 I_<Na>：一种对河豚毒素 (TTX) 具有抗性，仅在小 DRG 神经元 (I_<TTX-R/persist>) 中发现，另一种对 TTX 敏感，在中/大 DRG 神经元中发现（I_<TTX-S/persist>），现有数据表明前者最有可能由 Na_V1.9 介导，而后者可能由 Na_V1.9 介导。 Na_V1.6。为了证实这些可能性，我们进行了单细胞巢式 RT-PCR 结合并发膜片钳记录，并研究了已识别的 DRG 神经元中 I_<Na> 的 mRNA 表达和表型之间的相关性。 /persist> 是在 TTX 存在的情况下从 Na_V1.8 缺失突变小鼠的小 DRG 神经元中分离记录的，大多数与 Na_V1.9 转录物相关的小神经元都表现出来。 I_<TTX-R/persist>，证实介导 I_<TTX-R/persist> 的异构体可能是 Na_V1.9，然而，出乎意料的是，Na_V1.9 在相当数量的中/大神经元中也很明显。缺乏 I_<TTX-R/persist>。这些表明 I_<TTX-R/persist> 不仅仅依赖于 Na_V1.9 转录物的水平。有趣的是，Na_V1.9 转录物在幼稚小鼠的小 DRG 神经元中通常不存在，而在大多数突变体的小 DRG 神经元中，Na_V1.6 转录物的表达在相当大的部分中得到证实。然而，这些神经元没有表现出 I_<TTX-S/persist>，这表明 I_<TTX-S/persist> 可能不是由 Na_V1.6 携带的。