Document Detail

A CNS serotonergic mechanism in acute central hypovolemia in conscious rabbits?
MedLine Citation:
PMID:  1376801     Owner:  NLM     Status:  MEDLINE    
We tested whether a brainstem serotonergic mechanism influences the hemodynamic response to acute central hypovolemia. An inferior vena caval cuff was gradually inflated so that mean cardiac index (MCI) fell at a constant rate (approximately 8%/min). Under control conditions, mean systemic vascular conductance index (MSVCI) fell progressively until MCI had fallen by approximately 50% (compensatory phase), at which point MSVCI rose abruptly and arterial pressure fell to approximately 40 mm Hg (decompensatory phase). Intravenous methysergide delayed the decompensatory phase and at a critical dose (300-3,000 nmol) abolished it. Methysergide had similar effects when injected into the fourth ventricle, pontomedullary cistern, or lateral ventricle in doses that were 7-10% of the critical i.v. dose, but had no effect when injected into the spinal subarachnoid space. LY53857 was equipotent to methysergide. None of these treatments attenuated the vasoconstriction of the first, compensatory, phase. Partial depletion of neuronal serotonin (after p-chlorophenylalanine or 5,7-dihydroxytryptamine treatment) had no effect on either phase. We conclude that a serotonergic mechanism, probably located in the brainstem, may be involved in the decompensatory phase of acute central hypovolemia.
R G Evans; V Kapoor; J Ludbrook
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cardiovascular pharmacology     Volume:  19     ISSN:  0160-2446     ISO Abbreviation:  J. Cardiovasc. Pharmacol.     Publication Date:  1992 Jun 
Date Detail:
Created Date:  1992-07-21     Completed Date:  1992-07-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7902492     Medline TA:  J Cardiovasc Pharmacol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1009-17     Citation Subset:  IM    
Cardiovascular Research Laboratory, University of Melbourne Department of Surgery, Parkville, Victoria, Australia.
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MeSH Terms
5,7-Dihydroxytryptamine / pharmacology
Arginine Vasopressin / blood
Blood Pressure / drug effects
Cardiac Output / drug effects
Central Nervous System / drug effects,  physiopathology*
Ergolines / administration & dosage,  pharmacology
Fenclonine / pharmacology
Heart Rate / drug effects
Injections, Intravenous
Injections, Intraventricular
Methysergide / administration & dosage,  pharmacology
Renin / blood
Serotonin / physiology*
Serotonin Antagonists / administration & dosage,  pharmacology
Shock / physiopathology*
Reg. No./Substance:
0/Ergolines; 0/Serotonin Antagonists; 113-79-1/Arginine Vasopressin; 31363-74-3/5,7-Dihydroxytryptamine; 361-37-5/Methysergide; 50-67-9/Serotonin; 60634-51-7/LY 53857; 7424-00-2/Fenclonine; EC

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

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