title: The integration of depressive behaviors and cardiac dysfunction during an operational measure of depression: investigating the role of negative social experiences in an animal model.
abstract: OBJECTIVE
  There is a bidirectional association between depression and cardiovascular disease. The neurobiological mechanisms underlying this association may involve an inability to cope with disrupted social bonds. This study investigated in an animal model the integration of depressive behaviors and cardiac dysfunction after a disrupted social bond and during an operational measure of depression, relative to the protective effects of intact social bonds.
  
  
  METHODS
  Depressive behaviors in the forced swim test and continuous electrocardiographic parameters were measured in 14 adult, female socially monogamous prairie voles (rodents), after 4 weeks of social pairing or isolation.
  
  
  RESULTS
  After social isolation, animals exhibited (all values are mean ± standard error of the mean; isolated versus paired, respectively) increased heart rate (416 ± 14 versus 370 ± 14 bpm, p < .05) and reduced heart rate variability (3.3 ± 0.2 versus 3.9 ± 0.2 ln(ms(2))). During the forced swim test, isolated animals exhibited greater helpless behavior (immobility = 106 ± 11 versus 63 ± 11 seconds, p < .05), increased heart rate (530 ± 22 versus 447 ± 15 bpm, p < .05), reduced heart rate variability (1.8 ± 0.4 versus 2.7 ± 0.2 ln(ms(2)), p < .05), and increased arrhythmias (arrhythmic burden score = 181 ± 46 versus 28 ± 12, p < .05).
  
  
  CONCLUSIONS
  The display of depressive behaviors during an operational measure of depression is coupled with increased heart rate, reduced heart rate variability, and increased arrhythmias, indicative of dysfunctional behavioral and physiological stress coping abilities as a function of social isolation. In contrast, social pairing with a sibling is behaviorally protective and cardioprotective. The present results can provide insight into a possible social mechanism underlying the association between depression and cardiovascular disease in humans.
authors: Department of Psychology, Northern Illinois University, DeKalb, IL 60115, USA. angelagrippo@niu.edu
authors: Angela J
authors: AJ
authors: Grippo
authors: Julia A
authors: JA
authors: Moffitt
authors: Andrea
authors: A
authors: Sgoifo
authors: Amanda J
authors: AJ
authors: Jepson
authors: Suzanne L
authors: SL
authors: Bates
authors: Danielle L
authors: DL
authors: Chandler
authors: Neal
authors: N
authors: McNeal
authors: Kristin
authors: K
authors: Preihs
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology*; D003411:Arvicolinae; D001341:Autonomic Nervous System / Q000503:physiopathology; D001522:Behavior, Animal / Q000502:physiology*; D003863:Depression / Q000503:physiopathology*; D004195:Disease Models, Animal; D015716:Electrocardiography, Ambulatory; D005080:Exercise Test / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D009043:Motor Activity / Q000502:physiology; D012934:Social Isolation; D013315:Stress, Psychological / Q000503:physiopathology*; D013550:Swimming / Q000502:physiology; D013686:Telemetry / Q000379:methods