Department of Otolaryngology Head and Neck Surgery, Xijing Hospital, Air Force Medical University, Xi'an, Shannxi Province.
Eur J Histochem. 2023 Aug 7;67(3):3748. doi: 10.4081/ejh.2023.3748.
Lots of adrenergic receptors (ARs) are widely present across the auditory pathways and are positioned to affect auditory and vestibular functions. However, noradrenergic regulation in the cochlea has not been well characterized. In this study, a rat model of noise-induced hearing loss was developed to investigate the expression of α2A-adrenergic receptor (AR) after acoustic trauma, then, we investigated the expression of α2A-AR in the developing rat cochlea using immunofluorescence, qRT-PCR, and Western blotting. We found that the expression of α2A-AR significantly increased in rats exposed to noise compared with controls. Immunofluorescence analysis demonstrated that α2A-AR is localized on hair cells (HCs), spiral ganglion neurons (SGNs), and the stria vascularis (SV) in the postnatal developing cochlea from post-natal day (P) 0 to P28. Furthermore, we observed α2A-AR mRNA reached a maximum level at P14 and P28 when compared with P0, while no significant differences in α2A-AR protein levels at the various stages when compared with P0. This study provides direct evidence for the expression of α2A-AR in HCs, SGNs, and the SV of the cochlea, indicating that norepinephrine might play a vital role in hearing function within the cochlea through α2A-AR.
大量的肾上腺素能受体（ARs）广泛存在于听觉通路上，其位置可影响听觉和前庭功能。然而，去甲肾上腺素在耳蜗中的调节作用尚未得到很好的描述。在这项研究中，建立了噪声诱导听力损失的大鼠模型，以研究声创伤后α2A-肾上腺素能受体（AR）的表达，然后，我们使用免疫荧光、qRT-PCR 和 Western blot 研究了发育中大鼠耳蜗中α2A-AR 的表达。我们发现，与对照组相比，暴露于噪声的大鼠中α2A-AR 的表达显著增加。免疫荧光分析表明，α2A-AR 定位于毛细胞（HCs）、螺旋神经节神经元（SGNs）和血管纹（SV）中，在出生后第 0 天到第 28 天的发育耳蜗中。此外，与 P0 相比，我们观察到α2A-AR mRNA 在 P14 和 P28 时达到最大水平，而在 P0 时，α2A-AR 蛋白水平没有明显差异。这项研究为耳蜗中 HC、SGN 和 SV 中α2A-AR 的表达提供了直接证据，表明去甲肾上腺素可能通过α2A-AR 在耳蜗中的听力功能中发挥重要作用。
