Hajduczok G, Hade J S, Mark A L, Williams J L, Felder R B
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
Circ Res. 1991 Jul;69(1):66-75. doi: 10.1161/01.res.69.1.66.
A controversial issue in exercise physiology is the relative contribution of central command versus afferent input from contracting muscles and baroreceptors in the regulation of sympathetic nerve activity (SNA) during exercise. Recent studies of exercising humans have suggested that central command increases cutaneous sympathetic sudomotor nerve activity but have challenged the concept that central command contributes importantly to increases in sympathetic vasoconstrictor nerve activity to skin and skeletal muscle. The purpose of this study was to examine the influence of central command on renal SNA and lumbar SNA during spontaneous locomotion in decorticate cats. Unanesthetized decorticate cats that developed locomotion spontaneously or during electrical stimulation of the subthalamic locomotor region were studied in the presence and absence of input from skeletal muscle and baroreceptor afferents. Spontaneous rhythmic locomotion in the unparalyzed state was associated with significant increases in mean arterial pressure (MAP) from 106 +/- 10 to 133 +/- 11 mm Hg (p less than 0.05) and increases in renal SNA of 301 +/- 100% (p less than 0.05). During spontaneous fictive rhythmic locomotion in paralyzed cats, there were also significant (p less than 0.05) increases in MAP (43 +/- 6%), renal SNA (183 +/- 32%), and lumbar SNA (223 +/- 83%). Baroreceptor denervation did not attenuate increases in MAP, renal SNA, and lumbar SNA during locomotion. During electrical stimulation of the subthalamic locomotor region in paralyzed cats, MAP increased by 43 +/- 17% (p less than 0.05), and renal SNA increased by 175 +/- 47% (p less than 0.05). These findings indicate that central command is capable of increasing sympathetic neural drive in unanesthetized decorticate cats. This increase in sympathetic drive occurs even in the absence of feedback from contracting muscles or from arterial and cardiopulmonary baroreceptors.
运动生理学中一个有争议的问题是，在运动过程中，中枢指令与来自收缩肌肉和压力感受器的传入输入在交感神经活动（SNA）调节中所起的相对作用。对运动中的人类的最新研究表明，中枢指令会增加皮肤交感神经发汗运动神经活动，但对中枢指令对皮肤和骨骼肌交感缩血管神经活动增加有重要贡献这一概念提出了挑战。本研究的目的是在去皮质猫自发运动期间，研究中枢指令对肾交感神经活动和腰交感神经活动的影响。在有无骨骼肌和压力感受器传入输入的情况下，对自发或在电刺激丘脑底运动区时出现运动的未麻醉去皮质猫进行了研究。未瘫痪状态下的自发节律性运动与平均动脉压（MAP）从106±10显著升高至133±11 mmHg（p<0.05）以及肾交感神经活动增加301±100%（p<0.05）相关。在瘫痪猫的自发虚构节律性运动期间，MAP（43±6%）、肾交感神经活动（183±32%）和腰交感神经活动（223±83%）也有显著（p<0.05）增加。压力感受器去神经支配并未减弱运动期间MAP、肾交感神经活动和腰交感神经活动的增加。在瘫痪猫电刺激丘脑底运动区期间，MAP升高43±17%（p<0.05），肾交感神经活动增加175±47%（p<0.05）。这些发现表明，中枢指令能够增加未麻醉去皮质猫的交感神经驱动。即使在没有来自收缩肌肉或动脉及心肺压力感受器反馈的情况下，交感神经驱动也会增加。
