Document Detail


Contraction-by-contraction VO2 and computer-controlled pump perfusion as novel techniques to study skeletal muscle metabolism in situ.
MedLine Citation:
PMID:  20035064     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purpose of this research was to develop new techniques to 1) rapidly sample venous O(2) saturation to determine contraction-by-contraction oxygen uptake (Vo(2)), and 2) precisely control the rate and pattern of blood flow adjustment from one chosen steady state to another. An indwelling inline oximeter probe connected to an Oximetrix 3 meter was used to sample venous oxygen concentration ([O(2)]) (via fractional saturation of Hb with O(2)). Data from the Oximetrix 3 were filtered, deconvolved, and processed by a moving average second by second. Computer software and a program written in-house were used to control blood flow with a peristaltic pump. The isolated canine gastrocnemius muscle complex (GS) in situ was utilized to test these techniques. A step change in metabolic rate was elicited by stimulating GS muscles via their sciatic nerves (supramaximal voltage, 8 V; 50 Hz, 0.2-ms pulse width; train duration 200 ms) at a rate of either 1 contraction/2 s, or 2 contractions/3 s. With arterial [O(2)] maintained constant, blood flow and calculated venous [O(2)] were averaged over each contraction cycle and used in the Fick equation to calculate contraction-by-contraction Vo(2). About 5-8 times more data points were obtained with this method compared with traditional manual sampling. Software-controlled pump perfusion enabled the ability to mimic spontaneous blood flow on-kinetics (tau: 14.3 s) as well as dramatically speed (tau: 2.0 s) and slow (tau: 63.3 s) on-kinetics. These new techniques significantly improve on existing methods for mechanistically altering blood flow kinetics as well as accurately measuring muscle oxygen consumption kinetics during transitions between metabolic rates.
Authors:
Andr?s Hern?ndez; Matthew L Goodwin; Nicola Lai; Marco E Cabrera; James R McDonald; L Bruce Gladden
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Publication Detail:
Type:  Journal Article     Date:  2009-12-24
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  108     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-17     Completed Date:  2010-06-04     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  705-12     Citation Subset:  IM    
Affiliation:
Department of Kinesiology, Auburn University, Auburn, AL 36849-5323, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Automation, Laboratory
Dogs
Electric Stimulation
Female
Infusion Pumps*
Kinetics
Male
Models, Biological
Muscle Contraction*
Muscle, Skeletal / blood supply,  innervation,  metabolism*
Oximetry*
Oxygen / blood*
Oxygen Consumption*
Oxyhemoglobins / metabolism
Regional Blood Flow
Sciatic Nerve / physiology
Signal Processing, Computer-Assisted*
Software
Chemical
Reg. No./Substance:
0/Oxyhemoglobins; 7782-44-7/Oxygen

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


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