Document Detail

Central hemodynamic effects of oxytocin and interaction with magnesium and pregnancy in the isolated perfused rat heart.
MedLine Citation:
PMID:  9240588     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: Our purpose was to determine the cardiac effects of oxytocin in the isolated perfused rat heart model and to see whether pregnancy or pharmacologic levels of magnesium modifies the hormone's action. STUDY DESIGN: Hearts were excised from 30 female Sprague-Dawley rats (15 pregnant, 15 nonpregnant) and attached to a Langendorf's apparatus. Heart rate, left ventricular systolic pressure, and contractility were measured. Hearts were exposed serially to 2, 4, and 6 mU/ml concentrations of oxytocin. The experiment was repeated in 15 pregnant animals at a magnesium level of 5 mEq/L. RESULTS: Hearts from pregnant rats had lower heart rates than did hearts from nonpregnant animals. Oxytocin exposure diminished heart rate but increased left ventricular systolic pressure and contractility in a dose-dependent manner. Pregnancy did not alter this response. Magnesium levels of 5 mEq/L reversed the effects of oxytocin on contractility and left ventricular systolic pressure. CONCLUSION: Oxytocin is a negative chronotropic and positive inotropic agent in hearts from pregnant and nonpregnant rats. Magnesium reserves the positive inotropic effects of oxytocin.
C C Coulson; J M Thorp; D C Mayer; R C Cefalo
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  American journal of obstetrics and gynecology     Volume:  177     ISSN:  0002-9378     ISO Abbreviation:  Am. J. Obstet. Gynecol.     Publication Date:  1997 Jul 
Date Detail:
Created Date:  1997-08-19     Completed Date:  1997-08-19     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370476     Medline TA:  Am J Obstet Gynecol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  91-3     Citation Subset:  AIM; IM    
Department of Obstetrics and Gynecology, Penn State University, College of Medicine, Hershey, USA.
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MeSH Terms
Anti-Arrhythmia Agents / pharmacology*
Blood Pressure / drug effects,  physiology
Dose-Response Relationship, Drug
Drug Interactions
Drug Synergism
Heart / drug effects*,  physiology
Heart Rate / drug effects,  physiology
Hemodynamics / drug effects*,  physiology
Magnesium Sulfate / pharmacology*
Myocardial Contraction / drug effects,  physiology
Oxytocin / pharmacology*
Pregnancy, Animal / physiology*
Rats, Sprague-Dawley
Tocolytic Agents / pharmacology*
Reg. No./Substance:
0/Anti-Arrhythmia Agents; 0/Tocolytic Agents; 50-56-6/Oxytocin; 7487-88-9/Magnesium Sulfate

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