Activation of the otolith organs alters muscle sympathetic nerve activity, and attenuation of the vestibulosympathetic reflex is coupled with a drop in arterial blood pressure in the elderly.
How do different techniques of vestibular activation affect sympathetic nerve activity and arterial blood pressure in humans?
Evidence supports the existence of a vestibulosympathetic reflex in humans, which may play an important role in arterial blood pressure regulation, particularly in the elderly.
Activation of sympathetic neural traffic via the vestibular system is referred to as the vestibulosympathetic reflex. Investigations of the vestibulosympathetic reflex in humans have been limited to the past decade, and the importance of this reflex in arterial blood pressure regulation is still being determined. This review provides a summary of sympathetic neural responses to various techniques used to engage the vestibulosympathetic reflex. Studies suggest that activation of the semicircular canals using caloric stimulation and yaw rotation do not modulate muscle sympathetic nerve activity (MSNA) or skin sympathetic nerve activity (SSNA). In contrast, activation of the otolith organs appear to alter MSNA, but not SSNA. Specifically, head-down rotation and off-vertical axis rotation increase MSNA, while sinusoidal linear accelerations decrease MSNA. Galvanic stimulation, which results in a nonspecific activation of the vestibule, appears to increase MSNA if the mode of delivery is pulse trained. In conclusion, evidence strongly supports the existence of a vestibulosympathetic reflex in humans. Furthermore, attenuation of the vestibulosympathetic reflex is coupled with a drop in arterial blood pressure in the elderly, suggesting this reflex may be important in human blood pressure regulation.
Carter et al. (Thu,) conducted a review in Vestibulosympathetic reflex and arterial blood pressure regulation. Vestibular activation techniques was evaluated on Muscle sympathetic nerve activity (MSNA) and skin sympathetic nerve activity (SSNA). Activation of the otolith organs alters muscle sympathetic nerve activity, and attenuation of the vestibulosympathetic reflex is coupled with a drop in arterial blood pressure in the elderly.