Interaction of the vestibular system and baroreflexes on sympathetic nerve activity in humans.
Interaction of the vestibular system and baroreflexes on sympathetic nerve activity in humans.
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DOI：
10.1152/ajpheart.2000.279.5.h2399
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发表时间：
2000-11
期刊：
影响因子：
--
通讯作者：
C. Ray
中科院分区：
文献类型：
--
作者：
C. Ray
前庭耳石刺激改变了肌肉交感神经活动(MSNA)。这项研究考察了前庭系统和压力反射对人类MSNA的交互影响。在研究1中，以俯卧位受试者在下体负压(LBNP)为-10或-30毫米汞柱的情况下，在4分钟内测量MSNA。在下体负压试验的第三分钟，受试者将他们的头放在桌子的一端(头朝下旋转，HDR)以接触耳石器官。在4分钟内头部恢复到基线直立位置。LBNP在两个试验期间均使MSNA高于基线水平，在-30毫米汞试验期间增加幅度更大。在-10和-30 mm HgLBNP作用3min，HDR使MSNA进一步升高(分别为Delta32%和Delta34%；P<；0.01)。当头部直立时，在下体负压的第4分钟，MSNA恢复到HDR前的水平。在研究2中，测量卧床、下体负压时的MSNA，同时进行卧床和下体负压。在单独的HDR和LBNP试验中，MSNA反应的总和与HDR和LBNP一起进行时观察到的结果没有显著差异(-10和-30试验中，Delta131+/-28对Delta118+/-47个单位，Delta340+/-77对Delta380+/-90个单位)。这些结果表明，前庭耳石刺激可以增加卸载心、肺和动脉压力感受器反射时的MSNA。此外，人类的前庭交感神经反射和压力感受器反射之间的相互作用是相加的。这些研究表明，前庭交感神经反射可能通过增加交感神经流出来帮助人类抵御立位挑战。
Muscle sympathetic nerve activity (MSNA) is altered by vestibular otolith stimulation. This study examined interactive effects of the vestibular system and baroreflexes on MSNA in humans. In study 1, MSNA was measured during 4 min of lower body negative pressure (LBNP) at either -10 or -30 mmHg with subjects in prone posture. During the 3rd min of LBNP, subjects lowered their head over the end of a table (head-down rotation, HDR) to engage the otolith organs. The head was returned to baseline upright position during the 4th min. LBNP increased MSNA above baseline during both trials with greater increases during the -30-mmHg trial. HDR increased MSNA further during the 3rd min of LBNP at -10 and -30 mmHg (Delta32% and Delta34%, respectively; P < 0.01). MSNA returned to pre-HDR levels during the 4th min of LBNP when the head was returned upright. In study 2, MSNA was measured during HDR, LBNP, and simultaneously performed HDR and LBNP. The sum of MSNA responses during individual HDR and LBNP trials was not significantly different from that observed during HDR and LBNP performed together (Delta131 +/- 28 vs. Delta118 +/- 47 units and Delta340 +/- 77 vs. Delta380 +/- 90 units for the -10 and -30 trials, respectively). These results demonstrate that vestibular otolith stimulation can increase MSNA during unloading of the cardiopulmonary and arterial baroreflexes. Also, the interaction between the vestibulosympathetic reflex and baroreflexes is additive in humans. These studies indicate that the vestibulosympathetic reflex may help defend against orthostatic challenges in humans by increasing sympathetic outflow.