Document Detail


Venous tone and cardiac function in the South American rattlesnake Crotalus durissus: mean circulatory filling pressure during adrenergic stimulation in anaesthetised and fully recovered animals.
MedLine Citation:
PMID:  16169952     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effects of adrenergic stimulation on mean circulatory filling pressure (MCFP), central venous pressure (P(CV)) and stroke volume (Vs), as well as the effects of altered MCFP through changes of blood volume were investigated in rattlesnakes (Crotalus durissus). MCFP is an estimate of the upstream pressure driving blood towards the heart and is determined by blood volume and the activity of the smooth muscle cells in the veins (venous tone). MCFP can be determined as the plateau in P(CV) during a total occlusion of blood flow from the heart. Vs decreased significantly when MCFP was lowered by reducing blood volume in anaesthetised snakes, whereas increased MCFP through infusion of blood (up to 3 ml kg(-1)) only led to a small rise in Vs. Thus, it seems that end-diastolic volume is not affected by an elevated MCFP in rattlesnakes. To investigate adrenergic regulation on venous tone, adrenaline as well as phenylephrine and isoproterenol (alpha- and beta-adrenergic agonists, respectively) were infused as bolus injections (2 and 10 microg kg(-1)). Adrenaline and phenylephrine caused large increases in MCFP and P(CV), whereas isoproterenol decreased both parameters. This was also the case in fully recovered snakes. Therefore, adrenaline affects venous tone through both alpha- and beta-adrenergic receptors, but the alpha-adrenergic receptor dominates at the dosages used in the present study. Injection of the nitric oxide donor SNP caused a significant decrease in P(CV) and MCFP. Thus, nitric oxide seems to affect venous tone.
Authors:
Marianne Skals; Nini Skovgaard; Augusto S Abe; Tobias Wang
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  208     ISSN:  0022-0949     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2005 Oct 
Date Detail:
Created Date:  2005-09-19     Completed Date:  2006-02-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  3747-59     Citation Subset:  IM    
Affiliation:
Department of Zoophysiology, Institute of Biological Science, Aarhus University, Denmark. marianne.skals@biology.au.dk
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MeSH Terms
Descriptor/Qualifier:
Analysis of Variance
Anesthesia
Animals
Blood Circulation / drug effects*
Blood Volume
Brazil
Crotalus / physiology*
Dose-Response Relationship, Drug
Epinephrine / pharmacology*
Heart Function Tests
Muscle, Smooth, Vascular / drug effects*
Nitric Oxide Donors / pharmacology
Phenylephrine / pharmacology*
Stroke Volume / drug effects*
Venous Pressure / drug effects*
Chemical
Reg. No./Substance:
0/Nitric Oxide Donors; 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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