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


     

J Appl Physiol 82: 1472-1478, 1997;
8750-7587/97 $5.00
This Article
Right arrow Full Text Free
Right arrow Full Text (PDF) Free
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
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 Van Lunteren, E.
Right arrow Articles by Moyer, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Van Lunteren, E.
Right arrow Articles by Moyer, M.

Journal of Applied Physiology
Vol. 82, No. 5, pp. 1472-1478, May 1997
EXERCISE AND MUSCLE

Effects of hypoxia on diaphragm relaxation rate during fatigue

Erik Van Lunteren, Augusto Torres, and Michelle Moyer

Pulmonary and Critical Care Division, Department of Medicine, Case Western Reserve University, and Cleveland Veterans Affairs Medical Center, Cleveland, Ohio 44106

Received 1 September 1995; accepted in final form 21 November 1996.

Van Lunteren, Erik, Augusto Torres, and Michelle Moyer. Effects of hypoxia on diaphragm relaxation rate during fatigue. J. Appl. Physiol. 82(5): 1472-1478, 1997.---Skeletal muscle fatigue is associated with a slowing of relaxation rate. Hypoxia may increase the rate at which fatigue occurs, but, surprisingly, mild to moderate hypoxia has not been found to augment the degree of slowing of relaxation during fatigue. The present study tested the hypothesis that severe hypoxia interacts with fatigue in slowing the rate of muscle relaxation and that this can be modulated by altering membranous ionic conductances. Rat diaphragm muscle strips were studied in vitro while aerated with 95% O2-5% CO2 (normoxia) or 95% N2-5% CO2 (hypoxia). During continuous 0.1-Hz stimulation, relaxation rate and force remained stable over time, and relaxation rate was not slowed by hypoxia. Hypoxia accelerated force decline during continuous 5-Hz but not intermittent 20-Hz stimulation. During both 5- and 20-Hz stimulation, relaxation rate became slower over time as force declined, the extent of which was increased significantly by hypoxia. The extent of hypoxia-augmented slowing of relaxation rate during fatigue increased over time and was greater than expected for a given degree of force loss. 4-Aminopyridine did not attenuate or partially attenuated, whereas lowering extracellular Cl- concentration fully attenuated, the hypoxia-induced prolongation of relaxation rate during repetitive stimulation. Thus hypoxia slows relaxation rate to a greater extent than expected for a given degree of force decline, an effect that increases over time, is at most partially attenuated by lowering K+ conductance, and is fully attenuated by lowering membranous Cl- conductance.

skeletal muscle; contraction; potassium conductance; chloride conductance

0161-7567/97 $5.00 Copyright © 1997 the American Physiological Society




This article has been cited by other articles:


Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
X. Zhu, L. M. A. Heunks, E. M. M. Versteeg, H. F. M. van der Heijden, L. Ennen, T. H. van Kuppevelt, J. Vina, and P. N. R. Dekhuijzen
Hypoxia-induced dysfunction of rat diaphragm: role of peroxynitrite
Am J Physiol Lung Cell Mol Physiol, January 1, 2005; 288(1): L16 - L26.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
P. F. Klawitter and T. L. Clanton
Tension-time index, fatigue, and energetics in isolated rat diaphragm: a new experimental model
J Appl Physiol, January 1, 2004; 96(1): 89 - 95.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
L. M. A. Heunks, H. A. Machiels, R. de Abreu, X. Ping Zhu, H. F. M. van der Heijden, and P. N. R. Dekhuijzen
Free radicals in hypoxic rat diaphragm contractility: no role for xanthine oxidase
Am J Physiol Lung Cell Mol Physiol, December 1, 2001; 281(6): L1402 - L1412.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
C. Coirault, D. Chemla, and Y. Lecarpentier
Relaxation of diaphragm muscle
J Appl Physiol, October 1, 1999; 87(4): 1243 - 1252.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
H. F. M. van der Heijden, L. M. A. Heunks, H. Folgering, C. L. A. van Herwaarden, and P. N. R. Dekhuijzen
beta 2-Adrenoceptor agonists reduce the decline of rat diaphragm twitch force during severe hypoxia
Am J Physiol Lung Cell Mol Physiol, March 1, 1999; 276(3): L474 - L480.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Respir. Crit. Care Med.Home page
E. van LUNTEREN and M. MOYER
Electrophysiologic and Inotropic Effects of K+-Channel Blockade in Aged Diaphragm
Am. J. Respir. Crit. Care Med., September 1, 1998; 158(3): 820 - 826.
[Abstract] [Full Text] [PDF]

Home page
 J. Appl. Physiol.Home page
E. Van Lunteren, M. Moyer, and A. Torres
ATP-sensitive K+ channel blocker glibenclamide and diaphragm fatigue during normoxia and hypoxia
J Appl Physiol, August 1, 1998; 85(2): 601 - 608.
[Abstract] [Full Text] [PDF]


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