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


     

J Appl Physiol 92: 33-40, 2002;
8750-7587/02 $5.00
This Article
Right arrow Full Text Free
Right arrow Full Text (PDF) Free
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 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 Web of Science (9)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Nyhan, D.
Right arrow Articles by Berkowitz, D. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Nyhan, D.
Right arrow Articles by Berkowitz, D. E.
Vol. 92, Issue 1, 33-40, January 2002

Impaired pulmonary artery contractile responses in a rat model of microgravity: role of nitric oxide

Daniel Nyhan1, Soonyul Kim1, Stacey Dunbar2, Dechun Li1, Artin Shoukas2, and Dan E. Berkowitz1,2

Departments of 1 Anesthesiology and Critical Care Medicine and 2 Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287

Vascular contractile hyporesponsiveness is an important mechanism underlying orthostatic intolerance after microgravity. Baroreceptor reflexes can modulate both pulmonary resistance and capacitance function and thus cardiac output. We hypothesized, therefore, that pulmonary vasoreactivity is impaired in the hindlimb-unweighted (HLU) rat model of microgravity. Pulmonary artery (PA) contractile responses to phenylephrine (PE) and U-46619 (U4) were significantly decreased in the PAs from HLU vs. control (C) animals. NG-nitro-L-arginine methyl ester (10-5 M) enhanced the contractile responses in the PA rings from both C and HLU animals and completely abolished the differential responses to PE and U4 in HLU vs. C animals. Vasorelaxant responses to ACh were significantly enhanced in PA rings from HLU rats compared with C. Moreover, vasorelaxant responses to sodium nitroprusside were also significantly enhanced. Endothelial nitric oxide synthase (eNOS) and soluble guanlyl cyclase expression were significantly enhanced in PA and lung tissue from HLU rats. In marked contrast, the expression of inducible nitric oxide synthase was unchanged in lung tissue. These data support the hypothesis that vascular contractile responsiveness is attenuated in PAs from HLU rats and that this hyporesponsiveness is due at least in part to increased nitric oxide synthase activity resulting from enhanced eNOS expression. These findings may have important implications for blood volume distribution and attenuated stroke volume responses to orthostatic stress after microgravity exposure.

hindlimb unweighting; orthostatic intolerance; nitric oxide synthase; vasodilation; endothelium


This article has been cited by other articles:


Home page
 J. Appl. Physiol.Home page
S. M. Summers, Y. Hayashi, S. V. Nguyen, T. M. Nguyen, and R. E. Purdy
Hindlimb unweighting induces changes in the p38MAPK contractile pathway of the rat abdominal aorta
J Appl Physiol, July 1, 2009; 107(1): 121 - 127.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
S. Hwang, S. A. Shelkovnikov, and R. E. Purdy
Simulated microgravity effects on the rat carotid and femoral arteries: role of contractile protein expression and mechanical properties of the vessel wall
J Appl Physiol, April 1, 2007; 102(4): 1595 - 1603.
[Abstract] [Full Text] [PDF]

Home page
 J. Pharmacol. Exp. Ther.Home page
Y.-C. Chan, F.-P. Leung, X. Yao, C.-W. Lau, P. M. Vanhoutte, and Y. Huang
Raloxifene Relaxes Rat Pulmonary Arteries and Veins: Roles of Gender, Endothelium, and Antagonism of Ca2+ Influx
J. Pharmacol. Exp. Ther., March 1, 2005; 312(3): 1266 - 1271.
[Abstract] [Full Text] [PDF]

Home page
 J Clin PharmacolHome page
A. Graebe, E. L. Schuck, P. Lensing, L. Putcha, and H. Derendorf
Physiological, Pharmacokinetic, and Pharmacodynamic Changes in Space
J. Clin. Pharmacol., August 1, 2004; 44(8): 837 - 853.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
A. Papadopoulos and M. D. Delp
Effects of hindlimb unweighting on the mechanical and structure properties of the rat abdominal aorta
J Appl Physiol, February 1, 2003; 94(2): 439 - 445.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online