EFFECTS OF BEDREST ON FOREARM MUSCLE REFLEXES

这个项目的总体目标是检查2周卧床休息对交感神经对有节奏和静态前臂运动的反应的影响。我们假设交感神经反应会增加，因为乳酸生成和前臂间质体积会增加。我们进一步假设，前臂握力锻炼和/或间歇性前臂压迫将作为对策，以消除卧床的影响。在项目的第一年，我们将检查卧床对交感神经反应的影响：静态练习，有节奏的前臂锻炼和不自主的二头肌收缩。由于静态运动中交感放电的增加主要是由于代谢受体的兴奋，因此静态运动中的实验将有助于确定代谢受体的活性是否因睡眠而增强。有节奏的前臂运动实验将进行，以检查机械感受器活动和/或中央指挥活动是否被卧床治疗增强。我们将进行不自主肱二头肌收缩实验，以确定人类前臂的机械敏感传入神经是否会在2周的卧床期间致敏。将使用最先进的人体生理学技术，包括微神经摄影和核磁共振。

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.