| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Medical Physiology B, Panum Institute, University of Copenhagen, Denmark.
1. In ten young men the ventilatory, cardiovascular, catecholamine and metabolic responses to maximal dynamic leg exercise on a stationary bicycle were followed during partial neuromuscular blockade with tubocurarine. Maximal exercise was performed when the drug effect was at its maximum as well as during the subsequent reduction in the effect allowing a gradually increasing work intensity. The results were compared with those obtained during submaximal and maximal exercise performed without tubocurarine. Partial neuromuscular blockade decreased hand-grip strength to 41 +/- 1.1% (S.E. of mean) and the maximal work load to 27 +/- 2.4% of control values. Voluntary effort was maximal and the rate of perceived exertion was high at all levels of exercise with tubocurarine indicating a maintained intense central nervous motor command. 2. During maximal action of the drug oxygen uptake was 1.67 +/- 0.11 l/min while only 0.91 +/- 0.13 l/min (P less than 0.01) at the same work intensity without neuromuscular blockade. This difference may reflect a dominant reliance on fast-twitch muscle fibres when work was performed under the influence of tubocurarine. 3. Compared at a given oxygen uptake ventilation was higher during work with tubocurarine than during control exercise (e.g. 55 +/- 4.2 and 40 +/- 2.2 l/min, respectively (P less than 0.01), at a mean oxygen uptake of 1.9 l/min), while heart rate did not differ significantly (146 +/- 4.4 and 139 +/- 3.0 beats/min). With decreasing drug effect both variables increased towards the maximum values of 138 +/- 4.5 l/min and 183 +/- 3.9 beats/min, respectively, achieved in control experiments at an oxygen uptake of 3.8 +/- 0.2 l/min. Like heart rate the mean arterial blood pressure increased with increasing work load and was similar at a given oxygen uptake with and without tubocurarine. 4. During maximal exercise at peak tubocurarine effect plasma adrenaline and noradrenaline concentrations were smaller than during control maximum, 1.6 +/- 0.27 versus 3.4 +/- 0.55 nmol/l (P less than 0.01) and 7.5 +/- 1.3 versus 12.6 +/- 1.8 nmol/l (P less than 0.05), respectively. However, comparisons at identical oxygen uptake rates revealed that catecholamine responses were markedly enhanced during tubocurarine treatment. Also, blood lactate concentrations were smaller at peak tubocurarine action than during control maximum, 1.9 +/- 0.42 mmol/l and 6.1 +/- 0.49 mmol/l (P less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)
This article has been cited by other articles:
|
|
 |
|
  T. S. Larsen, P. Rasmussen, M. Overgaard, N. H. Secher, and H. B. Nielsen Non-selective {beta}-adrenergic blockade prevents reduction of the cerebral metabolic ratio during exhaustive exercise in humans J. Physiol., June 1, 2008; 586(11): 2807 - 2815. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Amann and J. A. Dempsey Reply from Markus Amann and Jerome A. Dempsey J. Physiol., April 1, 2008; 586(7): 2029 - 2030. [Full Text] [PDF]
|
|
|
|
|
|
B. Saltin Exercise hyperaemia: magnitude and aspects on regulation in humans J. Physiol., September 15, 2007; 583(3): 819 - 823. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. P. Dufour, S. Doutreleau, E. Lonsdorfer-Wolf, E. Lampert, C. Hirth, F. Piquard, J. Lonsdorfer, B. Geny, B. Mettauer, and R. Richard Deciphering the metabolic and mechanical contributions to the exercise-induced circulatory response: insights from eccentric cycling Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1641 - R1648. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Iellamo, M. Di Rienzo, D. Lucini, J. M. Legramante, P. Pizzinelli, P. Castiglioni, F. Pigozzi, M. Pagani, and G. Parati Muscle metaboreflex contribution to cardiovascular regulation during dynamic exercise in microgravity: insights from mission STS-107 of the space shuttle Columbia J. Physiol., May 1, 2006; 572(3): 829 - 838. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. A. Dawson, N. H. Secher, M. K. Dalsgaard, S. Ogoh, C. C. Yoshiga, J. Gonzalez-Alonso, A. Steensberg, and P. B. Raven Standing up to the challenge of standing: a siphon does not support cerebral blood flow in humans Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2004; 287(4): R911 - R914. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. K. Dalsgaard, S. Ogoh, E. A. Dawson, C. C. Yoshiga, B. Quistorff, and N. H. Secher Cerebral carbohydrate cost of physical exertion in humans Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2004; 287(3): R534 - R540. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. K. Dalsgaard, P. Ott, F. Dela, A. Juul, B. K. Pedersen, J. Warberg, J. Fahrenkrug, and N. H. Secher The CSF and arterial to internal jugular venous hormonal differences during exercise in humans Exp Physiol, May 1, 2004; 89(3): 271 - 277. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Jensen, H. B. Nielsen, K. Ide, P. L. Madsen, L. B. Svendsen, U. G. Svendsen, and N. H. Secher Cerebral Oxygenation During Exercise in Patients With Terminal Lung Disease* Chest, August 1, 2002; 122(2): 445 - 450. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. B. Nielsen, J. O. Clemmesen, C. Skak, P. Ott, and N. H. Secher Attenuated hepatosplanchnic uptake of lactate during intense exercise in humans J Appl Physiol, April 1, 2002; 92(4): 1677 - 1683. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Ide, A. Horn, and N. H. Secher Cerebral metabolic response to submaximal exercise J Appl Physiol, November 1, 1999; 87(5): 1604 - 1608. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Kjar, B. Hanel, L. Worm, G. Perko, S. F. Lewis, K. Sahlin, H. Galbo, and N. H. Secher Cardiovascular and neuroendocrine responses to exercise in hypoxia during impaired neural feedback from muscle Am J Physiol Regulatory Integrative Comp Physiol, July 1, 1999; 277(1): R76 - R85. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
