Document Detail


The role of venous capacitance, circulating catecholamines, and heart rate in the hemodynamic response to increased temperature and hypoxia in the dogfish.
MedLine Citation:
PMID:  19176885     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hypoxia and increased temperature alter venous blood pressures in teleosts through active changes in venous tone. Elasmobranchs possess a capacious venous system but have limited adrenergic vascular innervation and subambient central venous pressure (P(cv)). In this study, we explored venous hemodynamic responses to acute temperature increase and moderate (6.9 kPa) and severe (2.5 kPa) hypoxia in the dogfish (Squalus acanthias). Normoxic dogfish at 10 degrees C had a P(cv) between -0.08 and -0.04 kPa and a mean circulatory filling pressure (P(mcf)) of approximately 0.12 kPa. At 16 degrees C, heart rate (f(H)), cardiac output (Q), and P(mcf) increased but P(cv) and plasma epinephrine and norepinephrine levels were unchanged. In contrast, moderate and severe hypoxia increased P(cv) and decreased Q and stroke volume (V(S)). f(H) decreased in severe hypoxia, whereas P(mcf) was unaffected despite elevated catecholamine levels. Atropine abolished hypoxic reductions in Q, V(S), and f(H), but P(cv) still increased. In contrast to the response in teleosts, this study on dogfish suggests that venous capacitance changes associated with warming and hypoxia are minimal and likely not mediated by circulating catecholamines. Thus hemodynamic status of the capacious elasmobranch venous circulation is potentially regulated by blood volume shifts from passive flow-mediated events and possibly through myogenic mechanisms.
Authors:
Erik Sandblom; Georgina K Cox; Steve F Perry; Anthony P Farrell
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-01-28
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  296     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-04-28     Completed Date:  2009-06-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R1547-56     Citation Subset:  IM    
Affiliation:
Faculty of Land and Food Systems, University of Ottawa, Ottawa, Ontario, Canada. erik.sandblom@zool.gu.se
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MeSH Terms
Descriptor/Qualifier:
Animals
Anoxia / physiopathology*
Cardiac Output / physiology
Catecholamines / blood*
Female
Heart Rate / physiology*
Hot Temperature
Male
Models, Animal
Squalus acanthias / physiology*
Temperature*
Veins / physiology*
Venous Pressure / physiology
Chemical
Reg. No./Substance:
0/Catecholamines

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


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