Document Detail

Effects of chronic psychosocial stress on cardiac autonomic responsiveness and myocardial structure in mice.
MedLine Citation:
PMID:  14962836     Owner:  NLM     Status:  MEDLINE    
Repeated single exposures to social stressors induce robust shifts of cardiac sympathovagal balance toward sympathetic dominance both during and after each agonistic interaction. However, little evidence is available regarding possible persistent pathophysiological changes due to chronic social challenge. In this study, male CD-1 mice (n = 14) were implanted with a radiotelemetry system for electrocardiographic recordings. We assessed the effects of chronic psychosocial stress (15-day sensory contact with a dominant animal and daily 5-min defeat episodes) on 1) sympathovagal responsiveness to each defeat episode, as measured via time-domain indexes of heart rate variability (R-R interval, standard deviation of R-R interval, and root mean square of successive R-R interval differences), 2) circadian rhythmicity of heart rate across the chronic challenge (night phase, day phase, and rhythm amplitude values), and 3) amount of myocardial structural damage (volume fraction, density, and extension of fibrosis). This study indicated that there was habituation of acute cardiac autonomic responsiveness, i.e., the shift of sympathovagal balance toward sympathetic dominance was significantly reduced across repeated defeat episodes. Moreover, animals exhibited significant changes in heart rate rhythmicity, i.e., increments in day and night values and reductions in the rhythm amplitude, but these were limited to the first 5 days of chronic psychosocial stress. The volume fraction of fibrosis was sixfold larger than in control animals, because of the appearance of many microscopic scarrings. In summary, although mice appeared to adapt to chronic psychosocial stress in terms of acute cardiovascular responsiveness and heart rate rhythmicity, structural alterations occurred at the myocardial level.
Tania Costoli; Alessandro Bartolomucci; Gallia Graiani; Donatella Stilli; Giovanni Laviola; Andrea Sgoifo
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-02-12
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  286     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2004 Jun 
Date Detail:
Created Date:  2004-05-18     Completed Date:  2004-06-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2133-40     Citation Subset:  IM    
Dipartimento di Biologia Evolutiva e Funzionale, Università di Parma, Parco Area delle Scienze 11A, 43100 Parma, Italy.
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MeSH Terms
Adaptation, Physiological / physiology
Chronic Disease
Circadian Rhythm / physiology
Heart / innervation*,  physiology*
Heart Rate / physiology
Mice, Inbred Strains
Motor Activity / physiology
Myocardium / pathology
Stress, Psychological / pathology,  physiopathology*
Sympathetic Nervous System / physiology*
Vagus Nerve / physiology*

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

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