Document Detail


Central venous pressure and mean circulatory filling pressure in the dogfish Squalus acanthias: adrenergic control and role of the pericardium.
MedLine Citation:
PMID:  16825417     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Subambient central venous pressure (Pven) and modulation of venous return through cardiac suction (vis a fronte) characterizes the venous circulation in sharks. Venous capacitance was estimated in the dogfish Squalus acanthias by measuring the mean circulatory filling pressure (MCFP) during transient occlusion of cardiac outflow. We tested the hypothesis that venous return and cardiac preload can be altered additionally through adrenergic changes of venous capacitance. The experiments involved the surgical opening of the pericardium to place a perivascular occluder around the conus arteriosus. Another control group was identically instrumented, but lacked the occluder, and was subjected to the same pharmacological protocol to evaluate how pericardioectomy affected cardiovascular status. Routine Pven was negative (-0.08+/-0.02 kPa) in control fish but positive (0.09+/-0.01 kPa) in the pericardioectomized group. Injections of 5 microg/kg body mass (Mb) of epinephrine and phenylephrine (100 microg/kg Mb) increased Pven and MCFP, whereas isoproterenol (1 microg/kg Mb) decreased both variables. Thus, constriction and relaxation of the venous vasculature were mediated through the respective stimulation of alpha- and beta-adrenergic receptors. Alpha-adrenergic blockade with prazosin (1 mg/kg Mb) attenuated the responses to phenylephrine and decreased resting Pven in pericardioectomized animals. Our results provide convincing evidence for adrenergic control of the venous vasculature in elasmobranchs, although the pericardium is clearly an important component in the modulation of venous function. Thus active changes in venous capacitance have previously been underestimated as an important means of modulating venous return and cardiac performance in this group.
Authors:
Erik Sandblom; Michael Axelsson; Anthony P Farrell
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-07-06
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  291     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2006 Nov 
Date Detail:
Created Date:  2006-10-09     Completed Date:  2006-11-29     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:  R1465-73     Citation Subset:  IM    
Affiliation:
Dept. of Zoology, Göteborg Univ., Box 463, Göteborg S-405 30, Sweden. erik.sandblom@zool.gu.se
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MeSH Terms
Descriptor/Qualifier:
Adrenergic Agonists / pharmacology
Adrenergic Antagonists / pharmacology
Animals
Blood Circulation / physiology*
Cardiac Output / drug effects,  physiology
Central Venous Pressure / physiology*
Epinephrine / pharmacology
Female
Male
Myocardial Contraction / drug effects,  physiology
Pericardiectomy
Pericardium / physiology*,  surgery
Phenylephrine / pharmacology
Prazosin / pharmacology
Receptors, Adrenergic / drug effects,  physiology*
Squalus acanthias / physiology*
Stroke Volume / drug effects,  physiology
Vascular Capacitance / physiology*
Chemical
Reg. No./Substance:
0/Adrenergic Agonists; 0/Adrenergic Antagonists; 0/Receptors, Adrenergic; 19216-56-9/Prazosin; 51-43-4/Epinephrine; 59-42-7/Phenylephrine

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


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