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Environmental Enrichment Alters the Impact of Social Stress on the Cardiovascular System
Author(s) -
Normann Marigny,
McNeal Neal,
Colburn William,
Dagner Ashley,
Ihm Elliott,
Toghraee Amir,
Woodbury Matthew,
Grippo Angela J
Publication year - 2017
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.31.1_supplement.843.5
Subject(s) - heart rate , social isolation , anxiety , heart rate variability , environmental enrichment , offspring , vagal tone , psychology , physiology , chronic stress , social stress , medicine , developmental psychology , biology , blood pressure , psychiatry , pregnancy , genetics
Stress has been linked to negative cardiovascular consequences in both humans and non‐human animals, such as an increased risk of cardiovascular disease (CVD) and mortality, as well as an increase in depressive and anxiety related behaviors. To combat the effects of stress, research has incorporated environmental enrichment (EE) into animal models of stress. EE involves exposure to novel items and other species‐relevant engaging stimuli such as nesting material and toys. EE has cognitive benefits, such as improving recognition, acquisition and retention of information; as well as psychological benefits, such as reducing anxiety‐related behaviors. This study utilized the prairie vole to investigate the potential protective effects of EE on behavior and cardiovascular function. Prairie voles have a social structure similar to humans, including social monogamy and co‐parenting of offspring, which are rare characteristics in rodents. In this study, female prairie voles were surgically implanted with radiotelemetry transmitters to measure continuous heart rate and heart rate variability [using standard deviation of normal‐to‐normal intervals (SDNN Index) and respiratory sinus arrhythmia (RSA)]. Each female was paired with a male partner for five days followed by a period of isolation for an additional five days. The females were subsequently placed into one of three conditions for ten days: (a) isolation in a standard cage, (b) isolation in an EE cage, or (c) re‐paired with their male partner. The females were then tested in the forced swim test (FST) for five minutes as an index of depressive behavior. Cardiovascular measures were recorded during all phases of the experiment. All animals experienced negative cardiovascular effects of isolation. During exposure to the various treatment conditions, heart rate in the EE and re‐paired groups returned to baseline, but remained elevated in the prolonged isolation group. Similar effects were found for RSA. SDNN Index was increased in the EE group (relative to baseline and isolation), but remained similar to the isolation phase under both the prolonged isolation and re‐paired conditions. In the FST, the animals in the prolonged isolation group spent twice as much time immobile than the EE or repaired groups, which were comparable, indicating lower levels of depressive behaviors in the EE and re‐paired groups. These results suggest that EE may be as beneficial for an animal's behavioral and cardiovascular health as being re‐paired with a previously socially‐bonded partner. EE or a similar non‐social experience may attenuate psychological and physiological consequences of social stress in humans. Support or Funding Information HL112350