Document Detail


Roles of lactate and catecholamines in the energetics of brief locomotion in an ectothermic vertebrate.
MedLine Citation:
PMID:  11352107     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We have investigated the magnitude and duration of excess post-exercise oxygen consumption (EPOC) in a lizard following a single bout of vigorous exercise of 5-60 s, common activity durations for many ectothermic vertebrates. Desert iguanas (Dipsosaurus dorsalis) were run for 5 s, 15 s, 30 s, or 60 s. Oxygen consumption (VO2) increased from 0.16 ml O2 g(-1) h(-1) at rest to 1.3-1.6 ml O2 g(-1) h(-1) during 5-60 s of running. EPOC duration increased with activity duration, ranging from 35-63 min. EPOC volume, the excess oxygen consumed post-exercise, doubled from 0.13 ml O2 g(-1) following 5 s of activity to 0.25 ml O2 g(-1) after 60 s. EPOC represented 91-98% of the total metabolic expense of the activity. EPOC durations were always shorter than the period required for lactate removal, illustrating that these two processes are not causally related. Alpha- and beta-adrenergic receptor blockade by phentolamine and propranolol had no effect on resting VO2 but depressed excess post-exercise oxygen consumption volumes 2540%. The extent of catechol stimulation post-exercise may be motivation or stimulus dependent. The data indicate that metabolic elevations post-exercise represent the majority of activity costs in lizards. The study suggests that EPOC of ectothermic vertebrates is sensitive to exercise duration and catecholamine release post-activity, even when activity periods are less than 60 s in duration.
Authors:
J M Nedrow; D A Scholnick; T T Gleeson
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology     Volume:  171     ISSN:  0174-1578     ISO Abbreviation:  J. Comp. Physiol. B, Biochem. Syst. Environ. Physiol.     Publication Date:  2001 Apr 
Date Detail:
Created Date:  2001-05-15     Completed Date:  2001-09-20     Revised Date:  2009-06-08    
Medline Journal Info:
Nlm Unique ID:  8413200     Medline TA:  J Comp Physiol B     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  237-45     Citation Subset:  IM    
Affiliation:
Department of Environmental, Population, and Organismic Biology, University of Colorado, Boulder 80309-0334, USA.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic Antagonists / pharmacology
Animals
Catecholamines / physiology*
Energy Metabolism / physiology*
Iguanas / physiology*
Lactic Acid / blood,  metabolism*
Motor Activity / physiology*
Osmolar Concentration
Oxygen Consumption / drug effects
Chemical
Reg. No./Substance:
0/Adrenergic Antagonists; 0/Catecholamines; 50-21-5/Lactic Acid

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


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