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


     

J Appl Physiol 56: 1378-1382, 1984;
8750-7587/84 $5.00
This Article
Right arrow Full Text (PDF)
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
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 Mullin, W. J.
Right arrow Articles by Baldwin, K. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Mullin, W. J.
Right arrow Articles by Baldwin, K. M.

Journal of Applied Physiology, Vol 56, Issue 5 1378-1382, Copyright © 1984 by American Physiological Society

ARTICLES

Adaptive responses of rats trained with reductions in exercise heart rate

W. J. Mullin, R. E. Herrick, V. Valdez and K. M. Baldwin

This study was designed to test the hypothesis that rats trained with marked reductions in exercise heart rate respond with adaptations indicative of increased intrinsic myocardial performance. Therefore, we measured changes in maximum work capacity (VO2max), biochemical-functional indexes of cardiac contractile capacity, and skeletal muscle oxidative capacity in normal-trained (NT) rats and in rats trained while receiving the selective cardiac beta 1-blocking drug atenolol (AT). Training consisted of treadmill running at approximately 80% VO2max (untrained) for 1-h duration, 6 days/wk, for a total of 8 wk. Exercise heart rate of the AT group was markedly reduced and averaged 140 beats/min below the NT group for any given session. Compared with sedentary controls, VO2max was increased by 11%, and red vastus lateralis muscle citrate synthase activity was increased by 28% in both AT and NT groups (P less than 0.05). There were no differences between trained and nontrained groups with regard to Ca2+-regulated myofibril adenosinetriphosphatase. In situ derived left ventricular pressure and the maximum rate of left ventricular pressure development were not augmented relative to sedentary control values when the trained hearts were either stimulated inotropically or maximally afterloaded . These findings suggest that maximum exercise capacity can be enhanced in rodents conditioned with and without limited elevation in exercise heart rate; however, this reduction of exercise heart rate acceleration does not provide a stimulus to enhance the intrinsic functional capacity of the rodent heart.


This article has been cited by other articles:


Home page
 Exp. Biol. Med.Home page
J. F. Carroll, J. J. Thaden, and A. M. Wright
A Comparison of Two Exercise Training Programs on Cardiac Responsiveness to {beta}-Stimulation in Obesity
Experimental Biology and Medicine, March 1, 2005; 230(3): 180 - 188.
[Abstract] [Full Text] [PDF]

Home page
 J. Exp. Biol.Home page
L. J. Mellors and C. J. Barclay
The energetics of rat papillary muscles undergoing realistic strain patterns
J. Exp. Biol., January 11, 2001; 204(21): 3765 - 3777.
[Abstract] [Full Text] [PDF]


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