Department of Cell Physiology and Pharmacology, University of Leicester, University Road, Leicester LE19HN, UK.
Mol Cell Neurosci. 2009 Dec;42(4):399-407. doi: 10.1016/j.mcn.2009.09.001. Epub 2009 Sep 16.
The spiral ganglion neurons (SGN) provide the afferent innervation of the hair cells in the organ of Corti and relay auditory information from the inner ear to the brain. Voltage-gated sodium channels (Na(V)) initiate and propagate action potentials that encode this sensory information but little is known regarding the subtypes expressed in these cells. We have used RT-PCR and immunohistochemistry to study the compliment and anatomical distribution of Na(V) channels in rodent SGN. Na(V)1.1, Na(V)1.6 and Na(V)1.7 were all detected at the mRNA level. Fluorescence or streptavidin-horseradish peroxidase immunohistochemistry extended these findings, demonstrating predominant localisation of Na(V)1.6 and Na(V)1.7 on SGN cell bodies and Na(V)1.1 on axonal processes. Dual labelling with peripherin demonstrated higher Na(V)1.6 and Na(V)1.7 expression on Type I rather than Type II neurons. These results provide evidence for selective expression and variations in the distribution of VGSC in the rodent SGN, which may guide further studies into afferent function in the auditory pathway and therapeutic approaches for diseases such as hearing loss and tinnitus.
螺旋神经节神经元 (SGN) 为耳蜗毛细胞提供传入神经支配，并将内耳的听觉信息传递给大脑。电压门控钠离子通道 (Na(V)) 引发并传播动作电位，编码这些感觉信息，但对于这些细胞中表达的亚型知之甚少。我们使用 RT-PCR 和免疫组织化学研究了啮齿动物 SGN 中 Na(V)通道的补体和解剖分布。在 mRNA 水平上均检测到 Na(V)1.1、Na(V)1.6 和 Na(V)1.7。荧光或链霉亲和素-辣根过氧化物酶免疫组织化学扩展了这些发现，表明 Na(V)1.6 和 Na(V)1.7 主要定位于 SGN 细胞体，而 Na(V)1.1 则定位于轴突过程。与 peripherin 的双重标记表明，在 I 型神经元而非 II 型神经元上表达更高的 Na(V)1.6 和 Na(V)1.7。这些结果为在啮齿动物 SGN 中 VGSC 的选择性表达和分布变化提供了证据，这可能为听觉通路传入功能的进一步研究以及听力损失和耳鸣等疾病的治疗方法提供指导。
