Document Detail


Prioritizing blood flow: cardiovascular performance in response to the competing demands of locomotion and digestion for the Burmese python, Python molurus.
MedLine Citation:
PMID:  20008365     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Individually, the metabolic demands of digestion or movement can be fully supported by elevations in cardiovascular performance, but when occurring simultaneously, vascular perfusion may have to be prioritized to either the gut or skeletal muscles. Burmese pythons (Python molurus) experience similar increases in metabolic rate during the digestion of a meal as they do while crawling, hence each would have an equal demand for vascular supply when these two actions are combined. To determine, for the Burmese python, whether blood flow is prioritized when snakes are digesting and moving, we examined changes in cardiac performance and blood flow in response to digestion, movement, and the combination of digestion and movement. We used perivascular blood flow probes to measure blood flow through the left carotid artery, dorsal aorta, superior mesenteric artery and hepatic portal vein, and to calculate cardiac output, heart rate and stroke volume. Fasted pythons while crawling experienced a 2.7- and 3.3-fold increase, respectively, in heart rate and cardiac output, and a 66% decrease in superior mesenteric flow. During the digestion of a rodent meal equaling in mass to 24.7% of the snake's body mass, heart rate and cardiac output increased by 3.3- and 4.4-fold, respectively. Digestion also resulted in respective 11.6- and 14.1-fold increases in superior mesenteric and hepatic portal flow. When crawling while digesting, cardiac output and dorsal aorta flow increased by only 21% and 9%, respectively, a modest increase compared with that when they start to crawl on an empty stomach. Crawling did triggered a significant reduction in blood flow to the digesting gut, decreasing superior mesenteric and hepatic portal flow by 81% and 47%, respectively. When faced with the dual demands of digestion and crawling, Burmese pythons prioritize blood flow, apparently diverting visceral supply to the axial muscles.
Authors:
Stephen M Secor; Scott E White
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  213     ISSN:  1477-9145     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2010 Jan 
Date Detail:
Created Date:  2009-12-16     Completed Date:  2010-02-22     Revised Date:  2010-05-19    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  78-88     Citation Subset:  IM    
Affiliation:
Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35487-0344, USA. ssecor@biology.as.ua.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Boidae / physiology*
Cardiac Output
Cardiovascular System / anatomy & histology
Digestion
Fasting
Heart / physiology
Hemodynamics*
Locomotion

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


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