Vestibular activation of sympathetic nerve activity

• Published in: Acta physiologica Scandinavica Vol. 177; no. 3; pp. 313 - 319
• Main Authors: Ray, C. A., Carter, J. R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.03.2003; Blackwell Science
• Subjects: Aerospace Medicine; Aged; Aging - physiology; Animals; Baroreflex - physiology; Biological and medical sciences; Blood Pressure - physiology; Electric Stimulation - methods; Female; Fundamental and applied biological sciences. Psychology; Head-Down Tilt - physiology; Hemodynamics. Rheology; Humans; Hypotension, Orthostatic - physiopathology; Male; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Muscle, Skeletal - physiology; Muscle, Smooth, Vascular - physiology; orthostatic intolerance; Physical Endurance - physiology; Posture - physiology; Reflex - physiology; Rotation; Space Flight; Space life sciences; Stress, Psychological - physiopathology; sympathetic nervous system; Sympathetic Nervous System - physiology; Vertebrates: cardiovascular system; Vertebrates: nervous system and sense organs; Vestibule, Labyrinth - physiology; vestibulosympathetic reflex; Non-Nasa Center; Nasa Discipline Neuroscience; Review; Review, Tutorial; Human; Sympathetic nerve; Reflex; Electrical activity; Electrophysiology; Activation; Sympathetic nervous system; Inner ear; Autonomic nervous system; Animal; vestibulosympathetic reflex; orthostatic intolerance; Arterial pressure; Blood pressure; Hemodynamics; Vestibular system; Orthostatic tolerance; NASA Discipline Neuroscience; Non-NASA Center
• ISSN: 0001-6772; 1365-201X
• DOI: 10.1046/j.1365-201X.2003.01084.x

AIM: The vestibulosympathetic reflex refers to sympathetic nerve activation by the vestibular system. Animal studies indicate that the vestibular system assists in blood pressure regulation during orthostasis. Although human studies clearly demonstrate activation of muscle sympathetic nerve activity (MSNA) during engagement of the otolith organs, the role of the vestibulosympathetic reflex in maintaining blood pressure during orthostasis is not well-established. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes indicates that it is a powerful and independent reflex. Ageing, which is associated with an increased risk for orthostatic hypotension, attenuates the vestibulosympathetic reflex. The attenuated reflex is associated with a reduction in arterial pressure. CONCLUSION: These findings suggest that the vestibulosympathetic reflex assists in blood pressure regulation in humans, but future studies examining this reflex in other orthostatically intolerant populations are necessary to address this hypothesis.