Exposure to juvenile stress exacerbates the behavioural consequences of exposure to stress in the adult rat

Int J Neuropsychopharmacol. 2005 Jun;8(2):163-73. doi: 10.1017/S1461145704004808. Epub 2004 Nov 17.

Abstract

To examine the effects of exposure to post-weaning pre-puberty (juvenile) stress on the emotional and cognitive abilities in response to exposure to stress in adulthood, we first exposed rats to a platform stress at the age of 28 d. Two months later the rats were exposed to acute swim stress. Rats exposed to both stressors showed a higher level of anxiety (as measured both in open-field and startle response tests) than controls or rats exposed to either the juvenile or the adulthood stressor. In the Morris water-maze, rats that were exposed to both juvenile and adulthood stress performed better than the other groups. In a second experiment we verified that the effect of the juvenile stress was indeed age-dependent. One group was exposed at the age of 26-28 d and again at the age of 60 d (juvenile + adulthood stress); the other group was exposed to the first stressor at the age of 60-62 d and to the second at the age of 90 d [adulthood (60) + adulthood (90) stress]. Juvenile + adulthood stress had a significantly greater effect than exposure to stress twice in adulthood, on anxiety level and on the performance in the water-maze. Finally, in a third experiment we found that the juvenile+adulthood stress group swam faster and tended to explore the central area more than the other groups--a finding that could explain their better performance on the first trial of the spatial task. These results indicate that an exposure to a relatively brief juvenile stressful experience has profound and long-lasting effects on the ability to cope with stress in adulthood.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aging / psychology*
  • Analysis of Variance
  • Animals
  • Animals, Newborn
  • Behavior, Animal
  • Exploratory Behavior / physiology
  • Male
  • Maze Learning / physiology
  • Rats
  • Rats, Wistar
  • Reaction Time / physiology
  • Sexual Maturation / physiology*
  • Spatial Behavior / physiology*
  • Stress, Psychological / physiopathology*
  • Swimming