Kv4钾离子通道在前庭传入介导的传出神经元活化中的作用

Vestibular system is the main part to control the body posture balance and visual stability whose structure is complex. Vestibular level I and level II afferent neurons in rat can project to the efferent neurons directly. Immunohistochemical studies confirmed the expression of Kv4.3 and 4.2 ion channel subunits in vestibular afferent neurons. And the regulation of neuronal excitability related with potassium current is the cellular mechanism of learning and memory, which has been the consensus. In this project, we use molecular biology and electrophysiology methods to make clear the role and mechanism of Kv4 potassium channels in the vestibular afferent neurons in perceiving peripheral afferent information changes. The specific research program is as follows: 1. Using the cFos protein immunohistochemical staining and field potential recording, to verify the corresponding relationship which the vestibular efferent neuron excitability changes with the afferent information. 2. To observe the distribution of Kv4 potassium channels in the neurons of Ach and CGRP positive vestibular efferent neurons by ATED ultra-high resolution confocal laser scanning microscopy. 3. By four-channel two-photon microscopy patch-clamp technique, to record the excitability changes of efferent neurons mediated by vestibular afferent activity after administration of Kv4 channel agonists and antagonists. Through the research of this project, we can provide data to support the further research on the regulatory function and possible mechanism of vestibular efferent neurons in physiological and pathological conditions. And it will provide theoretical basis and ideas for the future study in the mechanisms of vestibular compensatory involved by the efferent neurons and the possible therapeutic targets Point.

前庭系统结构复杂，是控制人体姿势平衡和视觉稳定的主要部位。大鼠前庭Ⅰ级、Ⅱ级传入神经元均可直接投射到传出神经元，且传出神经元上有Kv4.2和4.3钾离子通道亚基表达，而钾电流有关的神经元兴奋性调节是学习记忆的细胞机制已成共识。本项目运用分子生物学和电生理学方法，阐明Kv4钾离子通道在前庭传出神经元感知外周传入信息变化的作用和机制。研究内容：1.通过cFos蛋白免疫组化染色和场电位记录，验证传出神经元兴奋性随传入信息变化的对应关系。2.通过高分辨率激光共聚焦成像技术观察Kv4钾通道在Ach、CGRP阳性传出神经元上的分布和表达。3. 通过双光子显微镜膜片钳技术记录用Kv4阻断剂、Ach和CGRP及其阻断剂灌流，传入介导的传出神经元兴奋性及A型钾电流变化，揭示Kv4的调节机制。本研究为探讨前庭传出神经元在生理及病理条件下的调节提供数据支持，为研究其参与代偿的机制和可能的治疗靶点提供思路和方法。

前庭系统结构复杂，是控制人体姿势平衡和视觉稳定的主要部位。前期研究提示大鼠前庭I级、II级传入神经元均可直接投射到传出神经元。钾电流有关的神经元兴奋性调节是学习记忆的细胞机制已成共识，而免疫组化研究证实前庭传出神经元中存在Kv4.2和4.3离子通道亚基的表达。本项目按照既定的项目设计，运用免疫组化、蛋白组学技术和电生理学方法，阐明Kv4钾离子通道在前庭传出神经元感知外周前庭传入信息变化的作用和机制，完成了相应的研究目标，并扩展研究了初级前庭传入中枢相应的调节和变化：1.通过cFos蛋白免疫组化染色和局部场电位记录，验证前庭传出神经元兴奋性确实存在与传入信息变化相对应的关系。2.通过免疫荧光和激光共聚焦成像技术观察Kv4钾离子通道在前庭传出神经元上的分布和表达变化。3.通过蛋白组学技术阐明外周前庭传入信息变化后初级前庭传入中枢神经元及前庭传出神经元Kv4钾离子通道蛋白的变化。4.通过膜片钳技术记录前庭传出区域神经元细胞基本电生理特性及A型钾电流特点，应用Kv4钾通道和主要神经递质拮抗剂后，探究前庭传入介导的传出神经元兴奋性突触后电流的改变。通过本研究，提出前庭传出系统携带Kv4.2与Kv4.3钾离子通道，它可能是外周前庭受到兴奋性刺激时的保护和调节机制之一，为探讨前庭传出神经元在生理及病理条件下的调节功能及机制提供数据支持，并为今后研究前庭传出神经元参与代偿的机制和可能的治疗靶点提供方法和思路。