Ia. Kerman et Bj. Yates, REGIONAL AND FUNCTIONAL DIFFERENCES IN THE DISTRIBUTION OF VESTIBULOSYMPATHETIC REFLEXES, American journal of physiology. Regulatory, integrative and comparative physiology, 44(3), 1998, pp. 824-835
Although considerable evidence suggests that the vestibular system reg
ulates sympathetic outflow during movement and changes in posture, lit
tle is known about relative vestibular influences on activity of diffe
rent sympathetic nerves and sympathetic efferents with different funct
ions. In the present study, we demonstrated that; electrical stimulati
on of the vestibular nerve in the cat elicited responses in sympatheti
c nerves innervating the head and abdominal viscera. This observation
suggests that activity of sympathetic efferents innervating multiple b
ody regions is affected by vestibular signals. These responses were at
tenuated by >80% when blood pressure was increased to >160 mmHg. Becau
se raising blood pressure decreases the responsiveness of vasoconstric
tor fibers, the simplest explanation tion for these data is that the v
estibular system provides particularly strong inputs to components of
the sympathetic nervous system that regulate peripheral vascular resis
tance. Furthermore, the relative magnitude of vestibule sympathetic re
flexes was over four times larger in one sympathetic nerve composed ma
inly of vasoconstrictor efferents (renal nerve) than another nerve (ex
ternal carotid nerve) containing similar types of fibers. Collectively
, these data indicate that the vestibular system has selective influen
ces on sympathetic outflow to particular tissues and body regions.