Journal article
Influence of simulated microgravity on the sympathetic response to exercise
American journal of physiology. Regulatory, integrative and comparative physiology, Vol.272(2), pp.R570-R575
02/01/1997
DOI: 10.1152/ajpregu.1997.272.2.R570
PMID: 9124480
Abstract
Rats exposed to simulated conditions of microgravity exhibit reductions in aerobic exercise capacity that may be due to an impaired ability of the sympathetic nervous system (SNS) to mediate an increase in cardiac output and to redistribute blood flow. The purpose of this study was to quantify the sympathetic response to exercise in rats after exposure to 14 days of simulated microgravity or control conditions. To achieve this aim, rats were exposed to 14 days of head-down suspension (HDS) or cage control (CC) conditions. On day 14, norepinephrine (NE) synthesis was blocked with alpha-methyl-p-tyrosine, and the rate of NE depletion after synthesis blockade was used to estimate SNS activity in the left ventricle, spleen, and soleus muscle during treadmill exercise at 75% of maximal oxygen uptake. When compared with CC rats, the sympathetic response to exercise in HDS rats was characterized by a lower rate of NE depletion in the left ventricle (-82%) and spleen (-42%). The rate of NE depletion in the soleus muscle was 47% higher. These differences could contribute to the decrement in aerobic capacity of HDS rats by impairing their ability to augment cardiac output and to redirect blood flow to actively contracting skeletal muscle during exercise.
Details
- Title: Subtitle
- Influence of simulated microgravity on the sympathetic response to exercise
- Creators
- Christopher R Woodman - Department of Physiology, University of Arizona, Tucson 85721,USAKevin C Kregel - Department of Physiology, University of Arizona, Tucson 85721,USACharles M Tipton - Department of Physiology, University of Arizona, Tucson 85721,USA
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Regulatory, integrative and comparative physiology, Vol.272(2), pp.R570-R575
- DOI
- 10.1152/ajpregu.1997.272.2.R570
- PMID
- 9124480
- ISSN
- 0363-6119
- eISSN
- 1522-1490
- Language
- English
- Date published
- 02/01/1997
- Academic Unit
- Radiation Oncology; Provost Office Administration; Health and Human Physiology
- Record Identifier
- 9984213309302771
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