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Repetitive psycho‐social stress elicits enduring behavioural and pro‐arrhythmic effects in rats
Author(s) -
Nalivaiko Eugene,
Carnevali Luca,
Trombini Mimosa,
Rossi Stefano,
Manghi Massimo,
Baruffi Silvana,
Macchi Emilio,
Sgoifo Andrea
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1075.4
Subject(s) - anhedonia , social defeat , refractory period , medicine , qt interval , chronic stress , learned helplessness , circadian rhythm , electrophysiology , effective refractory period , depression (economics) , behavioural despair test , cardiology , rhythm , psychology , anesthesia , endocrinology , antidepressant , dopamine , hippocampus , clinical psychology , economics , macroeconomics
To determine whether chronic stress has long‐lasting effect on the heart, we assessed cardiac electrophysiological properties in an animal model of depression. Adult male Wild Groningen rats (n=8) were subjected to 12 sessions of social defeat by an aggressive conspecific over 4 weeks; 8 control rats were exposed to a new cage. During and after chronic stress, defeated animals had substantial reduction in the amplitude of circadian rhythms, had smaller body weight gain, and developed anhedonia (determined by sucrose preference test) and learned helplessness (determined by forced swim test). One week after termination of the stress protocol, animals were anesthetized, and high‐definition epicardial potential mapping was performed using 64‐electrode array. We found shortening of the QT interval and of the effective refractory period (ERP) in defeated rats (QT: 52±0.7 vs. 38.3±0.5 ms; QTc: 32.6±0.6 vs. 23.8±0.4 ms; ERP: 102±4 vs. 88±5 ms in in controls and stressed rats, respectively; p<0.05). Reduced myocardial refractoriness, considered to be a determinant of arrhythmogenesis, represents long‐lasting pro‐arrhythmic effects of chronic social stress. Supported by NHMRC.