Modulation of muscle sympathetic bursts by sinusoidal galvanic vestibular stimulation in human subjects
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- 作者：Leah R. Bent ; Philip S. Bolton and Vaughan G. Macefield
- 关键词：Vestibulosympathetic ; Posture ; Autonomic ; Cardiovascular ; Orthostatic hypotension
- 刊名：Experimental Brain Research
- 出版年：2006
- 出版时间：October, 2006
- 年：2006
- 卷：174
- 期：4
- 页码：701-711
- 全文大小：508 KB
- 刊物类别：Biomedical and Life Sciences
- 刊物主题：Biomedicine
Neurosciences
Neurology - 出版者：Springer Berlin / Heidelberg
- ISSN：1432-1106
文摘
There is controversy as to whether the vestibulosympathetic reflexes demonstrated in experimental animals actually exist in human subjects. While head-down neck flexion and off-vertical axis rotation can increase muscle sympathetic nerve activity (MSNA) in awake subjects, we recently showed that bipolar galvanic vestibular stimulation (GVS) does not. However, it is possible that our stimuli (2 mA, 1 s)—although capable of causing strong postural and occulomotor responses—were too brief. To address this issue we activated vestibular afferents using continuous sinusoidal (0.5–0.8 Hz, 60–100 cycles, ±2 mA) bipolar binaural GVS in 11 seated subjects. Sinusoidal GVS evoked robust vestibular illusions of “rocking in a boat” or “swinging from side to side.” Cross-correlation analysis revealed a cyclic modulation of MSNA ranging from 31 to 86% across subjects (mean ± SE 58 ± 5%), with total MSNA increasing by 156 ± 19% (P = 0.001). Furthermore, we documented de novo synthesis of sympathetic bursts that were coupled to the sinusoidal input, such that two bursts—rather than the obligatory single burst—could be generated within a cardiac interval. This demonstrates that the human vestibular apparatus exerts a potent facilitatory influence on MSNA that potentially operates independently of the baroreceptor system.