HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 100/5/1475    most recent 01585.2005v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Wilson, T. D. Articles by Yates, B. J. Search for Related Content PubMed PubMed Citation Articles by Wilson, T. D. Articles by Yates, B. J.

Effects of postural changes and removal of vestibular inputs on blood flow to the head of conscious felines

Departments of ¹Otolaryngology and ²Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania; ³Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada; and ⁴Department of Otolaryngology, University of Colorado Health Sciences Center, Denver, Colorado

Submitted 16 December 2005 ; accepted in final form 23 January 2006

Prior studies have shown that removal of vestibular inputs produces lability in blood pressure during orthostatic challenges (Holmes MJ, Cotter LA, Arendt HE, Cass SP, and Yates BJ. Brain Res 938: 62–72, 2002; Jian BJ, Cotter LA, Emanuel BA, Cass SP, and Yates BJ. J Appl Physiol 86: 1552–1560, 1999). Furthermore, these studies led to the prediction that the blood pressure instability results in susceptibility for orthostatic intolerance. The present experiments tested this hypothesis by recording common carotid blood flow (CCBF) in conscious cats during head-up tilts of 20, 40, and 60° amplitudes, before and after the surgical elimination of labyrinthine inputs through a bilateral vestibular neurectomy. Before vestibular lesions in most animals, CCBF remained stable during head-up rotations. Unexpectedly, in five of six animals, the vestibular neurectomy resulted in a significant increase in baseline CCBF, particularly when the laboratory was illuminated; on average, basal blood flow measured when the animals were in the prone position was 41 ± 17 (SE) % higher after the first week after the lesions. As a result, even when posturally related lability in CCBF occurred after removal of vestibular inputs, blood supply to the head was not lower than when labyrinthine inputs were present. These data suggest that vestibular influences on cardiovascular regulation are more complex than previously appreciated, because labyrinthine signals appear to participate in setting basal rates of blood flow to the head in addition to triggering dynamic changes in the circulation to compensate for orthostatic challenges.

vestibular system; orthostatic tolerance; carotid artery; cerebral blood flow

This article has been cited by other articles:

				T. D. Wilson, L. A. Cotter, J. A. Draper, S. P. Misra, C. D. Rice, S. P. Cass, and B. J. Yates Vestibular inputs elicit patterned changes in limb blood flow in conscious cats J. Physiol., September 1, 2006; 575(2): 671 - 684. [Abstract] [Full Text] [PDF]