| VO2 on-kinetics in isolated canine muscle in situ during slowed convective O2 delivery. | |
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MedLine Citation:
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PMID: 21979805 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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The purpose of this study was to examine VO(2) on-kinetics when the spontaneous blood flow (and therefore O(2) delivery) on-response was slowed by 25 and 50 s. The isolated gastrocnemius muscle complex (GS) in situ was studied in six anesthetized dogs during transitions from rest to a submaximal metabolic rate (≈50-70% of VO(2peak)). Four trials were performed: 1) Pre-Trial (PT), in which resting and steady-state blood flows were established, 2) Control Trial 20 (CT20), in which blood flow on-kinetics mean response time (MRT) was set at 20 s, 3) Experimental Trial 45 (EX45), in which blood flow on-kinetics MRT was set at 45 s, and 4) Experimental Trial 70 (EX70), in which the blood flow on-kinetics MRT was set at 70 s. Slowing O(2) delivery via slowing blood flow on-kinetics resulted in a linear slowing of the VO(2) on-kinetics response (R=0.96). Average MRT values for CT20, EX45, and EX70 VO(2) on-kinetics were (mean ± SD) 17 ± 2, 23 ± 4, and 26 ± 3 s, respectively (p < 0.05 among all). During these transitions, slowing blood flow resulted in greater muscle deoxygenation (as indicated by near infrared spectroscopy), suggesting that lower intracellular PO(2) values were reached. In this oxidative muscle, VO(2) and O(2) delivery are closely matched during the transition period from rest to steady-state contractions. In conjunction with our previous work showing that speeding O(2) delivery did not alter VO(2) on-kinetics under similar conditions, it appears that spontaneously perfused skeletal muscle operates at the nexus of sufficient and insufficient O(2) delivery in the transition from rest to contractions. |
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Authors:
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Matthew L Goodwin; Andrés Hernández; Nicola Lai; Marco E Cabrera; L Bruce Gladden |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-10-6 |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: - ISSN: 1522-1601 ISO Abbreviation: - Publication Date: 2011 Oct |
Date Detail:
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Created Date: 2011-10-7 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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1Auburn University. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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