Effects of vapourized THC and voluntary alcohol drinking during adolescence on cognition, reward, and anxiety-like behaviours in rats

Prog Neuropsychopharmacol Biol Psychiatry. 2021 Mar 2;106:110141. doi: 10.1016/j.pnpbp.2020.110141. Epub 2020 Oct 16.

Abstract

Cannabis and alcohol co-use is prevalent in adolescence, but the long-term behavioural effects of this co-use remain largely unexplored. The aim of this study is to investigate the effects of adolescent alcohol and Δ9-tetrahydracannabinol (THC) vapour co-exposure on cognitive- and reward-related behaviours. Male Sprague-Dawley rats received vapourized THC (10 mg vapourized THC/four adolescent rats) or vehicle every other day (from post-natal day (PND) 28-42) and had continuous voluntary access to ethanol (10% volume/volume) in adolescence. Alcohol intake was measured during the exposure period to assess the acute effects of THC on alcohol consumption. In adulthood (PND 56+), rats underwent behavioural testing. Adolescent rats showed higher alcohol preference, assessed using the two-bottle choice test, on days on which they were not exposed to THC vapour. In adulthood, rats that drank alcohol as adolescents exhibited short-term memory deficits and showed decreased alcohol preference; on the other hand, rats exposed to THC vapour showed learning impairments in the delay-discounting task. Vapourized THC, alcohol or their combination had no effect on anxiety-like behaviours in adulthood. Our results show that although adolescent THC exposure acutely affects alcohol drinking, adolescent alcohol and cannabis co-use may not produce long-term additive effects.

Keywords: Cannabis; Co-use; Ethanol; Neurodevelopment; Substance use.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Alcohol Drinking / adverse effects
  • Alcohol Drinking / psychology*
  • Alcohol Drinking / trends
  • Animals
  • Anxiety / chemically induced
  • Anxiety / psychology*
  • Choice Behavior / drug effects
  • Choice Behavior / physiology
  • Cognition / drug effects*
  • Cognition / physiology
  • Delay Discounting / drug effects
  • Delay Discounting / physiology
  • Dronabinol / administration & dosage*
  • Dronabinol / adverse effects
  • Male
  • Rats
  • Rats, Sprague-Dawley
  • Reward*
  • Vaping / adverse effects
  • Vaping / psychology*
  • Vaping / trends

Substances

  • Dronabinol

Grant support