EFFECTS OF BEDREST ON FOREARM MUSCLE REFLEXES

本项目的总体目标是检查2 数周的卧床休息对交感神经的反应有节律， 静态前臂练习。我们假设交感神经反应 会增加，因为乳酸的产生和前臂 间隙体积将增加。我们进一步假设， 前臂握力练习和/或不情愿的前臂压缩将 作为对抗措施，消除卧床休息的影响。上 我们会研究卧床休息对 交感神经反应：静态练习，节奏前臂 运动和不自主的二头肌收缩。由于 静态运动时交感神经放电主要是由于 兴奋的代谢受体，在静态运动的实验将 有助于确定卧床休息是否能增强代谢受体活性。 实验将进行节奏前臂运动，以检查 无论机械感受器活动和/或中央命令活动是否 通过卧床休息来增强。肱二头肌不自主收缩实验 以确定机械敏感性传入神经 在人前臂中，通过2周的卧床休息而致敏。 最先进的人体生理学技术，包括显微神经造影术 将使用NMR。

The overall objectives of this project are to examine the effects of 2 weeks of bed rest on the sympathetic nerve responses to rhythmic and static forearm exercise. We postulate that sympathetic nerve responses will be increased because lactic acid production and forearm interstitial volume will be increased. We further postulate that forearm handgrip exercise and/or intermittant forearm compression will act as countermeasures to obviate the effects of bedrest. In the first year of the project, we will examine the effects of bedrest on the sympathetic nerve responses to: static exercises, rythmic forearm exercise and involuntary biceps contraction. Since increases in sympathetic discharge during static exercise are predominantly due to excitation of metaboreceptors, the experiments in static exercise will help determine if metaboreceptor activity is enhanced by bedrest. Experiments in rhythmic forearm exercise will be performed to examine whether mechanorecptor activity and/or central command activity is augmented by bedrest. The experiments in involuntary bicep contraction will be performed to determine whether mechanically-sensitive afferents in the human forearm are sensitized by the 2 week period of bedrest. State of the art human physiology techniques including microneurography and NMR will be used.