AJP - Regu AJP: Advances in Physiology Education
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol (August 15, 2002). doi:10.1152/ajpregu.00195.2002
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
283/5/R1221    most recent
00195.2002v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
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 Google Scholar
Google Scholar
Right arrow Articles by Cui, J.
Right arrow Articles by Crandall, C. G
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cui, J.
Right arrow Articles by Crandall, C. G

Articles in PresS, published online ahead of print August 15, 2002
Am J Physiol Regu Physiol, 10.1152/ajpregu.00195.2002
Submitted on April 3, 2002
Accepted on August 12, 2002

Phenylephrine-induced elevations in arterial blood pressure are attenuated in heat stressed humans

Jian Cui1, Thad E Wilson1, and Craig G Crandall2*

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

* To whom correspondence should be addressed. E-mail: Craig.Crandall{at}UTSouthwestern.edu.

To test the hypothesis that phenylephrine-induced elevations in blood pressure are attenuated in heat stressed humans, blood pressure was elevated via steady-state infusion of three doses of phenylephrine HCl in 10 healthy subjects in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature by ~0.5°C, muscle sympathetic nerve activity (MSNA), heart rate, cardiac output, and decreased total peripheral vascular resistance (TPR; all P<0.005), but did not change mean arterial blood pressure (MAP; p>0.05). At the highest dose of phenylephrine, the increase in MAP and TPR from pre-drug baselines were significantly attenuated during the heat stress ({Delta}MAP: 8.4± 1.2 mmHg; {Delta}TPR: 0.96± 0.85 PRU) when compared to normothermia ({Delta}MAP: 15.4 ± 1.4 mmHg, {Delta}TPR: 7.13 ± 1.18 PRU; all P<0.001). The sensitivity of baroreflex control of MSNA and heart rate, expressed as the slope of the relationship between MSNA and diastolic blood pressure as well as the slope of the relationship between heart rate and systolic blood pressure, respectively, were similar between thermal conditions (each P>0.05). These data suggest that phenylephrine-induced elevations in MAP are attenuated in heat stressed humans without affecting baroreflex control of MSNA or heart rate.




This article has been cited by other articles:


Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
K. D. Monahan and C. A. Ray
Cyclooxygenase inhibition and baroreflex sensitivity in humans
Am J Physiol Heart Circ Physiol, February 1, 2005; 288(2): H737 - H743.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
T. E. Wilson and C. A. Ray
Effect of thermal stress on the vestibulosympathetic reflexes in humans
J Appl Physiol, October 1, 2004; 97(4): 1367 - 1370.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
J. Cui, T. E. Wilson, and C. G. Crandall
Muscle sympathetic nerve activity during lower body negative pressure is accentuated in heat-stressed humans
J Appl Physiol, June 1, 2004; 96(6): 2103 - 2108.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
J. Cui, R. Zhang, T. E. Wilson, and C. G. Crandall
Spectral analysis of muscle sympathetic nerve activity in heat-stressed humans
Am J Physiol Heart Circ Physiol, March 1, 2004; 286(3): H1101 - H1106.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 2002 by the American Physiological Society.