Sex-dependent effects of maternal deprivation and adolescent cannabinoid treatment on adult rat behaviour

Addict Biol. 2011 Oct;16(4):624-37. doi: 10.1111/j.1369-1600.2011.00318.x. Epub 2011 Apr 26.

Abstract

Early life experiences such as maternal deprivation (MD) exert long-lasting changes in adult behaviour and reactivity to stressors. Adolescent exposure to cannabinoids is a predisposing factor in developing certain psychiatric disorders. Therefore, the combination of the two factors could exacerbate the negative consequences of each factor when evaluated at adulthood. The objective of this study was to investigate the long-term effects of early MD [24 hours at postnatal day (PND) 9] and/or an adolescent chronic treatment with the cannabinoid agonist CP-55,940 (0.4 mg/kg, PND 28-42) on diverse behavioural and physiological responses of adult male and female Wistar rats. We tested them in the prepulse inhibition (PPI) of the startle response and analysed their exploratory activity (holeboard) and anxiety (elevated plus maze, EPM). In addition, we evaluated their adrenocortical reactivity in response to stress and plasma leptin levels. Maternal behaviour was measured before and after deprivation. MD induced a transient increase of maternal behaviour on reuniting. In adulthood, maternally deprived males showed anxiolytic-like behaviour (or increased risk-taking behaviour) in the EPM. Adolescent exposure to the cannabinoid agonist induced an impairment of the PPI in females and increased adrenocortical responsiveness to the PPI test in males. Both, MD and adolescent cannabinoid exposure also induced sex-dependent changes in plasma leptin levels and body weights. The present results indicate that early MD and adolescent cannabinoid exposure exerted distinct sex-dependent long-term behavioural and physiological modifications that could predispose to the development of certain neuropsychiatric disorders, though no synergistic effects were found.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenocorticotropic Hormone / blood
  • Analgesics / pharmacology*
  • Animals
  • Arousal / drug effects
  • Attention / drug effects
  • Behavior, Animal / drug effects*
  • Body Weight / drug effects
  • Cannabinoids / pharmacology*
  • Cyclohexanols / pharmacology*
  • Exploratory Behavior / drug effects
  • Female
  • Hypothalamo-Hypophyseal System / drug effects
  • Inhibition, Psychological
  • Injections, Intraperitoneal
  • Leptin / blood
  • Male
  • Maternal Deprivation*
  • Maze Learning / drug effects
  • Motor Activity / drug effects
  • Organ Size / drug effects
  • Pituitary-Adrenal System / drug effects
  • Rats
  • Rats, Wistar
  • Risk-Taking
  • Sensory Gating / drug effects
  • Sex Factors

Substances

  • Analgesics
  • Cannabinoids
  • Cyclohexanols
  • Leptin
  • 3-(2-hydroxy-4-(1,1-dimethylheptyl)phenyl)-4-(3-hydroxypropyl)cyclohexanol
  • Adrenocorticotropic Hormone