Part II: Strain- and sex-specific effects of adolescent exposure to THC on adult brain and behaviour: Variants of learning, anxiety and volumetric estimates.
R J Keeley, J Trow, C Bye, R J McDonald
Behavioural Brain Research July 15, 2015 DOI: 10.1016/j.bbr.2015.01.001 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Controlled experimental animal study Peer reviewed |
|---|---|
| Population | Male and female Long-Evans hooded (LER) and Wistar (WR) rats |
| Intervention | THC |
| Duration | 14 consecutive days of THC administration following puberty onset, with assessment in adulthood |
| Topics | Cannabis Anxiety |
| Keywords | Behavior Brain volumetrics Rat Sex Strain |
| Key findings | Adolescent THC exposure produced long-term behavioral and brain-volume changes in adult rats, but the pattern varied by strain and sex. All behavioral tasks except motor learning, and associated brain volumes, were altered by injection or THC, with handled and vehicle controls also showing injection effects. The authors argue that strain should be considered when assessing vulnerability to adolescent cannabis exposure. |
Abstract
Marijuana is one of the most highly used psychoactive substances in the world, and its use typically begins during adolescence, a period of substantial brain development. Females across species appear to be more susceptible to the long-term consequences of marijuana use. Despite the identification of inherent differences between rat strains including measures of anatomy, genetics and behaviour, no studies to our knowledge have examined the long-term consequences of adolescent exposure to marijuana or its main psychoactive component, Δ(9)-tetrahydrocannabinol (THC), in males and females of two widely used rat strains: Long-Evans hooded (LER) and Wistar (WR) rats. THC was administered for 14 consecutive days following puberty onset, and once they reached adulthood, changes in behaviour and in the volume of associated brain areas were quantified. Rats were assessed in behavioural tests of motor, spatial and contextual learning, and anxiety. Some tasks showed effects of injection, since handled and vehicle groups were included as controls. Performance on all tasks, except motor learning, and the volume of associated brain areas were altered with injection or THC administration, although these effects varied by strain and sex group. Finally, analysis revealed treatment-specific correlations between performance and brain volumes. This study is the first of its kind to directly compare males and females of two rat strains for the long-term consequences of adolescent THC exposure. It highlights the importance of considering strain and identifies certain rat strains as susceptible or resilient to the effects of THC.
Comparable studies
Other preclinical and animal studies on cannabis for anxiety, most cited first.
Citations in the library
Cited by 5
- Cannabinoids, interoception, and anxiety. Pharmacology, Biochemistry, and Behavior May 1, 2019
- Concomitant THC and stress adolescent exposure induces impaired fear extinction and related neurobiological changes in adulthood. Neuropharmacology January 2019
- Short-Term Genetic Selection for Adolescent Locomotor Sensitivity to Delta9-Tetrahydrocannabinol (THC). Behavior genetics May 2018
- Effect of repeated juvenile exposure to Δ9‑tetrahydrocannabinol on anxiety-related behavior and social interactions in adolescent rats. Neurotoxicology and Teratology 2018
- Part III: Principal component analysis: bridging the gap between strain, sex and drug effects. Behavioural Brain Research July 15, 2015
Cites 10
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- Puberty as a highly vulnerable developmental period for the consequences of cannabis exposure. Addiction Biology June 2008
and 5 more in the library