Journal of Applied Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Appl Physiol 94: 2113-2118, 2003. First published January 10, 2003; doi:10.1152/japplphysiol.00067.2002
8750-7587/03 $5.00
This Article
Right arrow Full Text Free
Right arrow Full Text (PDF) Free
Right arrow All Versions of this Article:
94/6/2113    most recent
00067.2002v1
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (9)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Wilson, T. E.
Right arrow Articles by Crandall, C. G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Wilson, T. E.
Right arrow Articles by Crandall, C. G.
Vol. 94, Issue 6, 2113-2118, June 2003

Effects of 14 days of head-down tilt bed rest on cutaneous vasoconstrictor responses in humans

Thad E. Wilson1, Manabu Shibasaki1, Jian Cui1, Benjamin D. Levine1,2, and Craig G. Crandall1,2

1 Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, Dallas 75231; and 2 Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75235

This study tested the hypothesis that head-down tilt bed rest (HDBR) reduces adrenergic and nonadrenergic cutaneous vasoconstrictor responsiveness. Additionally, an exercise countermeasure group was included to identify whether exercise during bed rest might counteract any vasoconstrictor deficits that arose during HDBR. Twenty-two subjects underwent 14 days of strict 6° HDBR. Eight of these 22 subjects did not exercise during HDBR, while 14 of these subjects exercised on a supine cycle ergometer for 90 min a day at 75% of pre-bed rest heart rate maximum. To assess alpha -adrenergic vasoconstrictor responsiveness, intradermal microdialysis was used to locally administer norepinephrine (NE), while forearm skin blood flow (SkBF; laser-Doppler flowmetry) was monitored over microdialysis membranes. Nonlinear regression modeling was used to identify the effective drug concentration that caused 50% of the cutaneous vasoconstrictor response (EC50) and minimum values from the SkBF-NE dose-response curves. In addition, the effects of HDBR on nonadrenergic cutaneous vasoconstriction were assessed via the venoarteriolar response of the forearm and leg. HDBR did not alter EC50 or the magnitude of cutaneous vasoconstriction to exogenous NE administration regardless of whether the subjects exercised during HDBR. Moreover, HDBR did not alter the forearm venoarteriolar response in either the control or exercise groups during HDBR. However, HDBR significantly reduced the magnitude of cutaneous vasoconstriction due to the venoarteriolar response in the leg, and this response was similarly reduced in the exercise group. These data suggest that HDBR does not alter cutaneous vasoconstrictor responses to exogenous NE administration, whereas cutaneous vasoconstriction of the leg due to the venoarteriolar response is reduced after HDBR. It remains unclear whether attenuated venoarteriolar responses in the lower limbs contribute to reduced orthostatic tolerance after bed rest and spaceflight.

venoarteriolar reflex; norepinephrine; intradermal microdialysis; skin blood flow; simulated microgravity


This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
A. Gabrielsen and P. Norsk
Effect of spaceflight on the subcutaneous venoarteriolar reflex in the human lower leg
J Appl Physiol, September 1, 2007; 103(3): 959 - 962.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
K. Okazaki, Q. Fu, E. R. Martini, R. Shook, C. Conner, R. Zhang, C. G. Crandall, and B. D. Levine
Vasoconstriction during venous congestion: effects of venoarteriolar response, myogenic reflexes, and hemodynamics of changing perfusion pressure
Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2005; 289(5): R1354 - R1359.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
T. E. Wilson, R. Zhang, B. D. Levine, and C. G. Crandall
Dynamic autoregulation of cutaneous circulation: differential control in glabrous versus nonglabrous skin
Am J Physiol Heart Circ Physiol, July 1, 2005; 289(1): H385 - H391.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
T. E. Wilson, K. D. Monahan, D. S. Short, and C. A. Ray
Effect of age on cutaneous vasoconstrictor responses to norepinephrine in humans
Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2004; 287(5): R1230 - R1234.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
M. W. P. Bleeker, P. C. E. De Groot, J. A. Pawelczyk, M. T. E. Hopman, and B. D. Levine
Effects of 18 days of bed rest on leg and arm venous properties
J Appl Physiol, March 1, 2004; 96(3): 840 - 847.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
C. G. Crandall, M. Shibasaki, T. E. Wilson, J. Cui, and B. D. Levine
Prolonged head-down tilt exposure reduces maximal cutaneous vasodilator and sweating capacity in humans
J Appl Physiol, June 1, 2003; 94(6): 2330 - 2336.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online
Copyright © 2003 by the American Physiological Society.