| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Kinesiology, University of Waterloo, Waterloo N2L3G1; 2 Ottawa Heart Institute, University of Ottawa, Ottawa, Ontario K1Y4E9; and 3 Division of Sports Medicine, University of British Columbia, British Columbia, Canada V6T1Z3
To investigate the hypothesis that
acclimatization to altitude would result in a downregulation in muscle
Na+-K+-ATPase pump concentration, tissue
samples were obtained from the vastus lateralis muscle of six
volunteers (5 males and 1 female), ranging in age from 24 to 35 yr,
both before and within 3 days after a 21-day expedition to the summit
of Mount Denali, Alaska (6,194 m).
Na+-K+-ATPase, measured by the
[3H]ouabain-binding technique, decreased by
13.8% [348 ± 12 vs. 300 ± 7.6 (SE) pmol/g wet wt; P < 0.05]. No changes were found in the maximal activities
(mol · kg
protein
1 · h1)
of the mitochondrial enzymes, succinic dehydrogenase (3.63 ± 0.20 vs.
3.25 ± 0.23), citrate synthase (4.76 ± 0.44 vs. 4.94 ± 0.44), and
malate dehydrogenase (12.6 ± 1.8 vs. 12.7 ± 1.2). Similarly, the
expedition had no effect on any of the histochemical properties
examined, namely fiber-type distribution (types I, IIA, IIB, IC, IIC,
IIAB), area, capillarization, and succinic dehydrogenase activity. Peak
aerobic power (52.3 ± 2.1 vs. 50.6 ± 1.9 ml · kg1 · min1)
and body mass (76.9 ± 3.7 vs. 75.5 ± 2.9 kg) were also unaffected. We concluded that acclimatization to altitude results in a
downregulation in muscle Na+-K+-ATPase pump
concentration, which occurs without changes in oxidative potential and
other fiber-type histochemical properties.
enzyme, cation pump; fiber characteristics
This article has been cited by other articles:
|
|
 |
|
  M. J. Truijens, F. A. Rodriguez, N. E. Townsend, J. Stray-Gundersen, C. J. Gore, and B. D. Levine The effect of intermittent hypobaric hypoxic exposure and sea level training on submaximal economy in well-trained swimmers and runners J Appl Physiol, February 1, 2008; 104(2): 328 - 337. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Neya, T. Enoki, Y. Kumai, T. Sugoh, and T. Kawahara The effects of nightly normobaric hypoxia and high intensity training under intermittent normobaric hypoxia on running economy and hemoglobin mass J Appl Physiol, September 1, 2007; 103(3): 828 - 834. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Marconi, M. Marzorati, D. Sciuto, A. Ferri, and P. Cerretelli Economy of locomotion in high-altitude Tibetan migrants exposed to normoxia J. Physiol., December 1, 2005; 569(2): 667 - 675. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Aughey, C. J. Gore, A. G. Hahn, A. P. Garnham, S. A. Clark, A. C. Petersen, A. D. Roberts, and M. J. McKenna Chronic intermittent hypoxia and incremental cycling exercise independently depress muscle in vitro maximal Na+-K+-ATPase activity in well-trained athletes J Appl Physiol, January 1, 2005; 98(1): 186 - 192. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Lundby, H. Pilegaard, J. L. Andersen, G. van Hall, M. Sander, and J. A. L. Calbet Acclimatization to 4100 m does not change capillary density or mRNA expression of potential angiogenesis regulatory factors in human skeletal muscle J. Exp. Biol., October 15, 2004; 207(22): 3865 - 3871. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. CLAUSEN Na+-K+ Pump Regulation and Skeletal Muscle Contractility Physiol Rev, October 1, 2003; 83(4): 1269 - 1324. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y.-C. Ng, M. Nagarajan, K. N. Jew, L. C. Mace, and R. L. Moore Exercise training differentially modifies age-associated alteration in expression of Na+-K+-ATPase subunit isoforms in rat skeletal muscles Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2003; 285(4): R733 - R740. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C Juel, C Lundby, M Sander, J A L Calbet, and G van Hall Human skeletal muscle and erythrocyte proteins involved in acid-base homeostasis: adaptations to chronic hypoxia J. Physiol., April 15, 2003; 548(2): 639 - 648. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. L. Calbet, R. Boushel, G. Radegran, H. Sondergaard, P. D. Wagner, and B. Saltin Why is VO2 max after altitude acclimatization still reduced despite normalization of arterial O2 content? Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2003; 284(2): R304 - R316. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Green, B. Roy, S. Grant, C. Otto, A. Pipe, D. McKenzie, and M. Johnson Human skeletal muscle exercise metabolism following an expedition to Mount Denali Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1872 - R1879. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. J. Green, B. Roy, S. Grant, R. Hughson, M. Burnett, C. Otto, A. Pipe, D. McKenzie, and M. Johnson Increases in submaximal cycling efficiency mediated by altitude acclimatization J Appl Physiol, September 1, 2000; 89(3): 1189 - 1197. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
