Inner ear ion channels in healthy and diseased conditions

初级听觉传入神经元通过令人惊讶的微小的听觉诱发动作电位(AP)传导 轴突直径以惊人的速度和毫秒级的精度。听觉的反应特性 神经元(AN)对于低频(&lt；5 kHz)的声音是锁相的，这表明传导故障是罕见的。 然而，实现快速和锁相传导的神经机制却知之甚少。 我们假设ANS利用非均匀的节间、节间和斑块状的节间离子通道分布 以保持快速传导速度(CV)。这些功能可优化动作电位(AP)CV并防止AP 尽管有AN的结构限制，但仍有传导故障。 我们建议使用不同的敲除和敲除小鼠模型来检验潜在的假设 药理策略。我们利用光遗传学、高分辨率显微镜和 多种电生理方法。 我们的目标是确定1)轴突离子通道的表达、共定位和相互作用。我们将聘用 多学科方法评估轴突中特定离子通道的表达分布。2) 神经突起中特定离子通道之间的功能和物理相互作用。某些事物的接近程度 通道塑造了ANS的AP，以实现高速传导。我们将使用邻近连接试验(PLA)，活细胞 成像，以及空间和时间分辨率记录，以量化蛋白质-蛋白质相互作用。3)轴突 离子通道的体外和体内的功能作用的离子通道，形成一个AP的CV将被检查。我们 将使用对神经元的动力学、电压依赖性和电导的膜片钳分析来确定 通过计算研究，揭示了反应特性和变异系数差异的潜在机制。 因此，我们将解决解剖投影和信号处理的复杂性以及随后 会改变AP CV的结构和离子电导的变化。这一信息是必要的步骤 开发听力损失的治疗方法。

Primary auditory afferent neurons conduct sound-evoked action potentials (APs) through surprisingly small- diameter axons at remarkable speed and with millisecond precision. The response properties of the auditory neuron (AN) are phased-locked for low-frequency (<5 kHz) sounds, suggesting that conduction failure is a rarity. However, the neural mechanisms that enable swift and phase-locked conduction are poorly understood. We hypothesize that ANs utilize non-uniform nodal, internodal, and patchy nodal ionic channel distribution to maintain fast conduction velocity (CV). These features optimize action potential (AP) CV and prevent AP conduction failure despite the structural limitations of the AN. We propose to test the underlying hypotheses using various knockin and knockout mouse models and pharmacological strategies. We utilize innovations such as optogenetics, high-resolution microscopy, and multiple electrophysiological approaches. We aim to determine 1) AN axonal ion channels' expression, colocalization, and interactions. We will employ multidisciplinary approaches to assess the expression distribution of specific ionic channels in AN axons. 2) The functional and physical interactions between specific ionic channels in AN neurites. The proximity of certain channels shapes the APs of ANs for high-speed conduction. We will use proximity ligation assay (PLA), live-cell imaging, and spatial and temporal resolution recordings to quantify the protein-protein interactions. 3) Axonal ionic channels' ex vivo and in vivo functional roles of ion channels that shape AN AP CV will be examined. We will use patch-clamp analyses of the kinetics, voltage dependence, and conductance in AN neurons to determine the underlying mechanisms for the differences in response properties and CV using computational studies. Thus, we will address the complexity of anatomic projections and signal processing and subsequent alterations of the structural and ionic conductances that would alter AP CV. This information is a necessary step toward developing treatments for hearing loss.