Behavioral and physiological consequences of enrichment loss in rats

Psychoneuroendocrinology. 2017 Mar;77:37-46. doi: 10.1016/j.psyneuen.2016.11.040. Epub 2016 Dec 2.


Significant loss produces the highest degree of stress and compromised well-being in humans. Current rodent models of stress involve the application of physically or psychologically aversive stimuli, but do not address the concept of loss. We developed a rodent model for significant loss, involving removal of long-term access to a rewarding enriched environment. Our results indicate that removal from environmental enrichment produces a profound behavioral and physiological phenotype with depression-like qualities, including helplessness behavior, hypothalamo-pituitary-adrenocortical axis dysregulation and overeating. Importantly, this enrichment removal phenotype was prevented by antidepressant treatment. Furthermore, the effects of enrichment removal do not occur following relief from chronic stress and are not duplicated by loss of exercise or social contact.

Keywords: Depression; Environmental enrichment; Imipramine; Loss; Stress; Weight gain.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antidepressive Agents / pharmacology
  • Antidepressive Agents / therapeutic use
  • Behavior, Animal / drug effects
  • Behavior, Animal / physiology*
  • Depression / drug therapy
  • Depression / physiopathology*
  • Diet
  • Disease Models, Animal
  • Environment*
  • Feeding Behavior / physiology*
  • Housing, Animal
  • Hypothalamo-Hypophyseal System / drug effects
  • Hypothalamo-Hypophyseal System / physiopathology*
  • Pituitary-Adrenal System / drug effects
  • Pituitary-Adrenal System / physiopathology*
  • Rats
  • Reward
  • Social Behavior
  • Stress, Psychological / drug therapy
  • Stress, Psychological / physiopathology


  • Antidepressive Agents