The spiral ganglion neurons (SGNs) are the primary afferent neurons in the spiral ganglion (SG), while their degeneration or loss would cause sensorineural hearing loss. As a cardiac-derived hormone, atrial natriuretic peptide (ANP) plays a critical role in cardiovascular homeostasis through binding to its functional receptors (NPR-A and NPR-C). ANP and its receptors are widely expressed in the mammalian nervous system where they could be implicated in the regulation of multiple neural functions. Although previous studies have provided direct evidence for the presence of ANP and its functional receptors in the inner ear, their presence within the cochlear SG and their regulatory roles during auditory neurotransmission and development remain largely unknown. Based on our previous findings, we investigated the expression patterns of ANP and its receptors in the cochlear SG and dissociated SGNs and determined the influence of ANP on neurite outgrowth in vitro by using organotypic SG explants and dissociated SGN cultures from postnatal rats. We have demonstrated that ANP and its receptors are expressed in neurons within the cochlear SG of postnatal rat, while ANP may promote neurite outgrowth of SGNs via the NPR-A/cGMP/PKG pathway in a dose-dependent manner. These results indicate that ANP would play a role in normal neuritogenesis of SGN during cochlear development and represents a potential therapeutic candidate to enhance regeneration and regrowth of SGN neurites.

中文翻译：

---

心房钠尿肽通过 cGMP 依赖性方式在体外改善螺旋神经节神经元的神经突生长


螺旋神经节神经元（SGN）是螺旋神经节（SG）中的主要传入神经元，其退化或丧失会导致感音神经性听力损失。作为一种心脏源性激素，心房钠尿肽 (ANP) 通过与其功能受体（NPR-A 和 NPR-C）结合，在心血管稳态中发挥关键作用。 ANP 及其受体在哺乳动物神经系统中广泛表达，可能参与多种神经功能的调节。尽管之前的研究已经为内耳中 ANP 及其功能受体的存在提供了直接证据，但它们在耳蜗 SG 中的存在以及它们在听觉神经传递和发育过程中的调节作用仍然很大程度上未知。基于我们之前的研究结果，我们研究了 ANP 及其受体在耳蜗 SG 和游离 SGN 中的表达模式，并通过使用出生后大鼠的器官型 SG 外植体和游离 SGN 培养物确定了 ANP 对体外神经突生长的影响。我们已经证明ANP及其受体在出生后大鼠耳蜗SG内的神经元中表达，而ANP可以通过NPR-A/cGMP/PKG途径以剂量依赖性方式促进SGN的神经突生长。这些结果表明，ANP 在耳蜗发育过程中 SGN 的正常神经突发生中发挥作用，并且是增强 SGN 神经突再生和再生长的潜在治疗候选者。