Adult rats exposed to early-life social isolation exhibit increased anxiety and conditioned fear behavior, and altered hormonal stress responses

Jodi L. Lukkes, Maxim V. Mokin, Jamie L Scholl, Gina L Forster

Research output: Contribution to journalArticle

162 Citations (Scopus)

Abstract

Social isolation of rodents during development is thought to be a relevant model of early-life chronic stress. We investigated the effects of early-life social isolation on later adult fear and anxiety behavior, and on corticosterone stress responses, in male rats. On postnatal day 21, male rats were either housed in isolation or in groups of 3 for a 3 week period, after which, all rats were group-reared for an additional 2 weeks. After the 5-week treatment, adult rats were examined for conditioned fear, open field anxiety-like behavior, social interaction behavior and corticosterone responses to restraint stress. Isolates exhibited increased anxiety-like behaviors in a brightly-lit open field during the first 10 min of the test period compared to group-reared rats. Isolation-reared rats also showed increased fear behavior and reduced social contact in a social interaction test, and a transient increase in fear behavior to a conditioned stimulus that predicted foot-shock. Isolation-reared rats showed similar restraint-induced increases in plasma corticosterone as group-reared controls, but plasma corticosterone levels 2 h after restraint were significantly lower than pre-stress levels in isolates. Overall, this study shows that isolation restricted to an early part of development increases anxiety-like and fear behaviors in adulthood, and also results in depressed levels of plasma corticosterone following restraint stress.

Original languageEnglish (US)
Pages (from-to)248-256
Number of pages9
JournalHormones and Behavior
Volume55
Issue number1
DOIs
StatePublished - Jan 1 2009

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Social Isolation
Fear
Anxiety
Corticosterone
Interpersonal Relations
Psychological Stress
Foot
Rodentia
Shock
Control Groups

Keywords

  • Corticosterone
  • Foot-shock
  • Open field
  • Restraint stress
  • Social interaction

ASJC Scopus subject areas

  • Endocrinology
  • Behavioral Neuroscience
  • Endocrine and Autonomic Systems

Cite this

Adult rats exposed to early-life social isolation exhibit increased anxiety and conditioned fear behavior, and altered hormonal stress responses. / Lukkes, Jodi L.; Mokin, Maxim V.; Scholl, Jamie L; Forster, Gina L.

In: Hormones and Behavior, Vol. 55, No. 1, 01.01.2009, p. 248-256.

Research output: Contribution to journalArticle

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