Affiliations: [a] Departments of Otolaryngology and Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania, USA | [b] Laboratory of Neurophysiology, The Rockefeller University, New York, New York, USA
Note: [1] Reprint address: Dr. Bill Yates, Department of Otolaryngology, University of Pittsburgh School of Medicine, Eye and Ear Institute, Rm. 106, 200 Lothrop Street, Pittsburgh, PA 15213. Tel (412) 647-9614; Fax: (412) 647-2080; E-mail: byates@pop.pitt.edu
Abstract: Electrical or natural stimulation of the vestibular system results in changes in blood pressure and respiratory motor output. An increase in excitatory drive on the sympathetic nervous system occurs during nose-up vestibular stimulation in cats; this response is appropriate to offset orthostatic hypotension that could result from nose-up body rotations during movements such as vertical climbing. In addition, transection of the vestibular nerves in anesthetized or awake cats compromises the ability to correct decreases in blood pressure that result from nose-up body tilt. The vestibular system also has influences on respiratory muscles; these effects are appropriate to participate in making adjustments in the activity of respiratory muscles that are necessary to offset mechanical constraints on these muscles that occur during changes in body position. These data thus suggest that the influences of the vestibular system on the autonomic and respiratory systems serve to maintain homeostasis during movement.
