AJP - Regu Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Regul Integr Comp Physiol 277: R419-R426, 1999;
0363-6119/99 $5.00
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
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 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 Iwase, S.
Right arrow Articles by Nagaoka, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Iwase, S.
Right arrow Articles by Nagaoka, S.
Vol. 277, Issue 2, R419-R426, August 1999

Sympathetic outflow to muscle in humans during short periods of microgravity produced by parabolic flight

Satoshi Iwase1, Tadaaki Mano1, Jian Cui1, Hiroki Kitazawa1, Atsunori Kamiya1, Seiji Miyazaki1, Yoshiki Sugiyama1, Chiaki Mukai2, and Shunji Nagaoka2

1 Department of Autonomic Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601; and 2 National Space Development Agency of Japan, Tsukuba 305, Japan

We have investigated the changes in muscle sympathetic nerve activity (MSNA) from the tibial nerve during brief periods of microgravity (µG) for ~20 s produced by parabolic flight. MSNA was recorded microneurographically from 13 quietly seated human subjects with their knee joints extended in a jet aircraft simultaneously with the electrocardiogram, the blood pressure wave (measured with a Finapres), the respiration curve, and the thoracic fluid volume (measured by impedance plethysmography). During quiet and seated parabolic flight, MSNA was activated in hypergravity and was suppressed in µG phasically. At the entry to hypergravity at 2 G just before µG, the thoracic fluid volume was reduced by 3.2 ± 3%, and the arterial blood pressure was lowered transiently and then gradually elevated from 89.5 ± 1.7 to 100.2 ± 1.7 mmHg, which caused the enhancement of MSNA by 91.4 ± 14.2%. At the entry to µG, the thoracic fluid volume was increased by 3.4%, which lowered the mean blood pressure to 77.9 ± 2.3 mmHg and suppressed the MSNA by 17.2%. However, this suppression lasted only ~10 s, followed by an enhancement of MSNA that continued for several seconds. We conclude that MSNA is suppressed and then enhanced during µG produced by parabolic flight. These changes in MSNA are in response not only to intrathoracic fluid volume changes but also to arterial blood pressure changes, both of which are caused by body fluid shifts induced by parabolic flight, and these changes are quite phasic and transient.

muscle sympathetic nerve activity; hypergravity; microneurography; baroreflex; weightlessness


This article has been cited by other articles:


Home page
 Am. J. Physiol. Heart Circ. Physiol.Home page
P-F. Migeotte, G. K. Prisk, and M. Paiva
Microgravity alters respiratory sinus arrhythmia and short-term heart rate variability in humans
Am J Physiol Heart Circ Physiol, June 1, 2003; 284(6): H1995 - H2006.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
H. Waki, T. Shimizu, K. Katahira, T. Nagayama, M. Yamasaki, and S.-I. Katsuda
Effects of microgravity elicited by parabolic flight on abdominal aortic pressure and heart rate in rats
J Appl Physiol, December 1, 2002; 93(6): 1893 - 1899.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
J. Cui, S. Iwase, T. Mano, N. Katayama, and S. Mori
Muscle sympathetic outflow during horizontal linear acceleration in humans
Am J Physiol Regulatory Integrative Comp Physiol, August 1, 2001; 281(2): R625 - R634.
[Abstract] [Full Text] [PDF]


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