Document Detail


Initial fall in skeletal muscle force development during ischemia is related to oxygen availability.
MedLine Citation:
PMID:  7868458     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We examined the hypothesis that the initial decline (first 1-2 min) in force development that occurs in working muscle when blood flow is halted is caused by O2 availability and not another factor related to blood flow. This was tested by reducing O2 delivery (muscle blood flow X arterial O2 content) to working muscle by either stopping blood flow [ischemia (I)] or maintaining blood flow with low arterial O2 content [hypoxemia (H)]. If initial decline in force development were similar between these two methods of reducing O2 delivery, it would suggest O2 availability as the common pathway. Isolated dog gastrocnemius muscle was stimulated at approximately 60-70% of maximal O2 uptake (1 isometric tetanic contraction every 2 s) until steady-state conditions of muscle blood flow and developed force were attained (approximately 3 min). Two conditions were then sequentially imposed on the working muscle: I, induced by shutting off pump controlling arterial perfusion of the muscle and clamping venous outflow, and H, induced by perfusing the muscle with deoxygenated blood (collected before testing while animal breathed N2) at steady-state blood flow level. Rates of the fall in force production in 17 matched conditions of H and I (approximately 40 s for each condition) were compared in 6 muscles tested. The blood perfusing the muscle during H had arterial PO2 = 8 +/- 1 (SE) Torr, arterial PCO2 = 37 +/- 1 Torr, and arterial pH = 7.39 +/- 0.03. The rate of decline in developed force was not significantly different (P = 0.46) between the 17 matched conditions of H (0.66 +/- 0.10 g force.g mass-1.s-1) and I (0.79 +/- 0.15 g force.g mass-1.s-1). These findings suggest that the initial fall in developed force in working skeletal muscle that occurs with ischemia is related to O2 availability.
Authors:
M C Hogan; R S Richardson; S S Kurdak
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  77     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1995-03-30     Completed Date:  1995-03-30     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2380-4     Citation Subset:  IM; S    
Affiliation:
Department of Medicine, University of California at San Diego, La Jolla 92093-0623.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Flow Velocity
Blood Gas Analysis
Dogs
Female
Ischemia / physiopathology*
Male
Muscle Fatigue / physiology*
Muscle, Skeletal / blood supply,  physiology*
Oxygen / blood
Oxygen Consumption / physiology*
Physical Exertion
Grant Support
ID/Acronym/Agency:
AR-40155/AR/NIAMS NIH HHS; HL-17731/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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