Sex differences in the effects of social and physical environment on novelty-induced exploratory behavior and cocaine-stimulated locomotor activity in adolescent rats

Elena Zakharova, Amy Starosciak, Dean Wade, Sari Izenwasser

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Many factors influence the rewarding effects of drugs such as cocaine. The present study was done to determine whether social and environmental factors alter behavior in adolescent male and female rats. On postnatal day (PND) 23, rats were housed in one of several same-sex conditions. Both social (number of rats per cage) and environmental (availability of toys) factors were manipulated. Socially isolated rats were housed alone (1 rat/cage) in an environment that either was impoverished (with no toys; II) or enriched (with toys; IE). Standard housing for these studies was social and impoverished, which was 2 rats/cage with no toys (SI2). Other rats were housed 2/cage with toys (SE2), or 3/cage with (SE3) or without (SI3) toys. On PND 37, novelty-induced locomotor activity was measured for 30. min. On PND 44-46, locomotor activity in response to an injection of 5. mg/kg cocaine was measured for 60. min each day. For male rats, only social conditions altered novelty-induced activity. Males housed in groups of three had the most activity, compared to pair-housed and isolated rats. For females, social and environmental enrichment interacted to alter novelty-induced activity. In contrast to males, isolated females had increased activity, compared to group-housed females. Further, isolated females in impoverished environments had more activity than isolated females in enriched environments and group-housed females in impoverished environments. The effect of environmental enrichment on cocaine-stimulated locomotor activity was altered depending upon the number of rats living in a cage for males. For females, only social conditions altered cocaine-stimulated behavior, with activity increasing with the number of rats in the cage, regardless of environmental enrichment. These data show that social and environmental enrichment differentially alter novelty-induced and cocaine-stimulated locomotor activity in adolescent male and female rats.

Original languageEnglish (US)
Pages (from-to)92-99
Number of pages8
JournalBehavioural Brain Research
Volume230
Issue number1
DOIs
StatePublished - Apr 21 2012

Keywords

  • Adolescent
  • Cocaine
  • Enrichment
  • Exploratory behavior
  • Locomotor activity

ASJC Scopus subject areas

  • Behavioral Neuroscience

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