Incidence of arrhythmias and heart rate variability in wild-type rats exposed to social stress.
Psychological stressors of different natures can induce different shifts of autonomic control on cardiac electrical activity, with either a sympathetic or a parasympathetic prevalence. Arrhythmia occurrence, R-R interval variability, and plasma catecholamine elevations were measured in male wild-type rats exposed to either a social stressor (defeat) or a nonsocial challenge (restraint). Electrocardiograms were telemetrically recorded, and blood samples were withdrawn through jugular vein catheters from normal, freely moving animals. Defeat produced a much higher incidence of arrhythmias (mostly ventricular premature beats), which were mainly observed in the 60-s time periods after attacks. The social challenge also induced a much stronger reduction of average R-R interval, a lower R-R interval variability (as estimated by the time-domain parameters standard deviation of mean R-R interval duration, coefficient of variance, and root mean square of successive differences in R-R interval duration), and higher elevations of venous plasma catecholamines compared with restraint. These autonomic and/or neuroendocrine data indicate that a social stressor such as defeat is characterized by both a higher sympathetic activation and a lower parasympathetic antagonism compared with a nonsocial restraint challenge, which results in a higher risk for ventricular arrhythmias.
Sgoifo
A
A
Center for Behavioral and Cognitive Neurosciences, Department of Animal Physiology, University of Groningen, Haren, The Netherlands.
de Boer
S F
SF
Westenbroek
C
C
Maes
F W
FW
Beldhuis
H
H
Suzuki
T
T
Koolhaas
J M
JM
D000374:Aggression / Q000502:physiology; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000453:epidemiology* / Q000209:etiology*; D004562:Electrocardiography; D004837:Epinephrine / Q000097:blood; D006339:Heart Rate / Q000502:physiology*; D008297:Male; D009638:Norepinephrine / Q000097:blood; D051381:Rats; D012930:Social Dominance; D013315:Stress, Psychological / Q000097:blood / Q000150:complications* / Q000503:physiopathology*
D009638:Norepinephrine; D004837:Epinephrine