Novelty-induced locomotion is positively associated with cocaine ingestion in adolescent rats; anxiety is correlated in adults

Pharmacol Biochem Behav. 2009 Jan;91(3):398-408. doi: 10.1016/j.pbb.2008.08.019. Epub 2008 Aug 28.

Abstract

The present studies assessed the roles of sex, age, novelty-seeking and plus-maze behavior on cocaine drinking in rats. Cocaine/saccharin solution was available in three daily, 5-hour sessions then a saccharin-only solution was also available in following sessions. In the one-bottle drinking phase, early and late adolescent males, post-natal day 28 (PN28) and PN42, consumed more cocaine/saccharin solution than young adults (PN65), but females did not exhibit significant age differences. Adolescents of both sexes consumed more cocaine/saccharin than adults during choice drinking. Saccharin availability in the two-bottle trials decreased cocaine/saccharin consumption in PN28 and PN65 rats. After a drug-free period, cocaine-stimulated locomotion was lower in cocaine/saccharin drinking than saccharin-only males, indicating tolerance. We tested the hypothesis that individual differences in pre-screened behavioral traits would correlate with cocaine/saccharin consumption in PN28 and PN65 male rats. High locomotor responses to novelty were associated with greater cocaine/saccharin drinking in adults in one-bottle sessions. In the subsequent choice drinking phase, correlations were age-specific. Adolescents with high novelty-induced locomotion and adults that spent less time on open arms of the elevated plus-maze drank more cocaine/saccharin. Thus, behavioral phenotypes correlated with individual differences in cocaine/saccharin consumption in an age-related manner.

Publication types

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

MeSH terms

  • Aging / psychology*
  • Animals
  • Anxiety / psychology*
  • Cocaine / chemistry
  • Cocaine / pharmacology
  • Cocaine-Related Disorders / psychology*
  • Data Interpretation, Statistical
  • Environment
  • Female
  • Male
  • Motor Activity / drug effects*
  • Pharmaceutical Solutions
  • Rats
  • Reward
  • Sex Characteristics

Substances

  • Pharmaceutical Solutions
  • Cocaine