Document Detail

Effects of an acute stressor on blood pressure and heart rate in rats pretreated with intracerebroventricular oxytocin injections.
MedLine Citation:
PMID:  17698297     Owner:  NLM     Status:  MEDLINE    
Oxytocin induces a long-lasting reduction of blood pressure in rats. The aim of the present study was to investigate the effects of an acute stressor on blood pressure and heart rate in rats previously exposed to repeated administration of intracerebroventricular (ICV) oxytocin. For this purpose oxytocin (0.3 microg, ICV) was administered to male rats once a day during 5 days. Blood pressure and heart rate were measured before and after treatment. In addition, blood pressure and heart rate were measured during 30 min after exposure to 10s of noise from an alarm clock. The oxytocin treatment reduced blood pressure significantly (systolic: 108+/-4.6 vs. 121+/-1.8, p<0.01, diastolic: 96+/-5.1 vs. 108+/-3.0, p<0.01), whereas heart rate remained unchanged. In contrast, systolic and diastolic blood pressure increased significantly after the exposure to the ringing alarm clock in the oxytocin-treated rats (p<0.05), and became equal to the blood pressure in controls. In addition, heart rate increased and stayed significantly higher in the oxytocin-treated rats compared to the controls during the 30 min observation period (ANOVA p<0.01). Twenty-four hours later, blood pressure was again significantly lower in the oxytocin-treated rats compared to controls (p<0.01). In conclusion, oxytocin decreased blood pressure without changing pulse rate. However, when the oxytocin-treated rats were subjected to the unexpected noise from a ringing alarm clock blood pressure and heart rate increased significantly. No such effect was observed in the control group. Thus repeated oxytocin treatment can, in spite of decreasing blood pressure during basal conditions, increase cardiovascular reactivity to some types of stressors.
Maria Petersson; Kerstin Uvnäs-Moberg
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-08-14
Journal Detail:
Title:  Psychoneuroendocrinology     Volume:  32     ISSN:  0306-4530     ISO Abbreviation:  Psychoneuroendocrinology     Publication Date:    2007 Sep-Nov
Date Detail:
Created Date:  2007-11-16     Completed Date:  2008-03-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7612148     Medline TA:  Psychoneuroendocrinology     Country:  England    
Other Details:
Languages:  eng     Pagination:  959-65     Citation Subset:  IM    
Department of Molecular Medicine and Surgery, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden.
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MeSH Terms
Blood Pressure / drug effects*
Drug Administration Schedule
Heart Rate / drug effects*
Injections, Intraventricular
Oxytocin / administration & dosage,  pharmacology*
Rats, Sprague-Dawley
Stress, Psychological / physiopathology*
Reg. No./Substance:

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

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