VESTIBULOSYMPATHETIC REFLEXES IN HUMANS

描述（改编自申请人摘要）：长期 主要研究者的目的是评价反射机制 调节人类心血管系统的基因 研究者已 最近证明，头向下颈部屈曲（HDNF）增加肌肉 交感神经活动（MSNA）。 这一发现表明， 前庭系统在调节MSNA中的作用。 总的假设是 在这个项目中评估的是，前庭系统起着重要的作用， 在人类交感神经系统调节中的作用。 这 将通过记录激活过程中人类的MSNA来评估假设 通过不同的头部运动来改变前庭系统。 在这项提案中， 本研究将检验以下假设：1. HDNF期间MSNA增加 因为前庭激活 2. 耳石器官但不是半圆形的 运河引起MSNA增加。 3. 前庭交感神经激活 反射调节由其他心血管反射引起的MSNA。 测试 在这些假设下，提出了以下具体目标的研究：1。 为了确定在不同水平和持续时间的HDNF期间MSNA对HDNF的反应， 颈部屈曲，并以不同的体位进行。 2. 以确定 MSNA在动态头部运动过程中的反应，激活了耳石 器官和半规管。 3. 为了确定HDNF的相互作用 （前庭交感神经反射）与其他心血管反射（例如， 动脉压力感受性反射）对人类MSNA的影响。 这些研究的设计将 提供了关于前庭调节交感神经的新知识， 人类的活动。 这些发现可能具有重要意义， 了解直立不耐受的原因，否则健康 受试者以及为什么直立不耐受在老年人中更普遍 以及长期暴露于微重力环境下的个体。

DESCRIPTION (Adapted from the applicant's abstract): The long-term objectives of the Principal Investigator are to evaluate reflex mechanisms that regulate the cardiovascular system in humans. The investigator has recently demonstrated that head-down neck flexion (HDNF) increases muscle sympathetic nerve activity (MSNA). This finding suggested a role of the vestibular system in regulating MSNA. The overall hypothesis to be evaluated in this project is that the vestibular system plays an important role in the regulation of the sympathetic nervous system in humans. This hypothesis will be evaluated by recording MSNA in humans during activation of the vestibular system by different head movements. In this proposal the following hypotheses will be tested: 1. Increases in MSNA during HDNF are due to vestibular activation. 2. Otolith organs but not semicircular canals elicit increases in MSNA. 3. Activation of the vestibulosympathetic reflex modulates MSNA elicited by other cardiovascular reflexes. To test these hypotheses, studies with the following specific aims are proposed: 1. To determine MSNA responses to HDNF during different levels and durations of neck flexion, and performed in different body positions. 2. To determine MSNA responses during dynamic head movements which activate both the otolith organs and semicircular canals. 3. To determine the interaction of HDNF (vestibulosympathetic reflex) with other cardiovascular reflexes (e.g., arterial baroreflex) on MSNA in humans. The design of these studies will provide new knowledge regarding vestibular regulation of sympathetic activity in humans. These findings may have important implications in understanding the cause of orthostatic intolerance in otherwise healthy subjects and why orthostatic intolerance is more prevalent in the elderly and in individuals following prolonged exposure to microgravity.