Male and female rat brains develop endocannabinoid signaling on different timelines

What the researchers found

Endocannabinoid-mediated long-term depression (eCB-LTD) was present in juvenile female rats but only appeared at puberty in males. Gene expression of eCB/vanilloid system components was sequential and sex-specific, with juvenile males showing elevated expression of CB1R-inhibiting proteins that blocked LTD.

Why it matters

If endocannabinoid signaling develops on different timelines in males and females, cannabis exposure during adolescence could have sex-specific effects on brain development, potentially explaining observed sex differences in cannabis-related outcomes.

The numbers in context

eCB-LTD present in juvenile females but absent until puberty in males; pharmacological inhibition of ABHD6 or MAGL (but not anandamide degradation) enabled LTD in young males

How the study worked

Animal study examining sex-specific cellular and synaptic trajectories in rat prefrontal cortex from adolescence to adulthood using electrophysiology, gene expression analysis, and pharmacological manipulation of endocannabinoid pathways.

What this study cannot tell us

Rat model may not directly translate to human brain development. Focused on prefrontal cortex layer 5 only. Did not directly test how exogenous cannabis exposure interacts with these developmental trajectories.

How to read the evidence

Detailed mechanistic animal study with multiple methodological approaches, but translation to human brain development is uncertain.

When this study was published

Published 2023

The bigger picture

These findings provide a biological basis for why cannabis may affect developing male and female brains differently, with implications for understanding sex-specific vulnerability to cannabis-related cognitive effects during adolescence.

Questions still open

• Does earlier eCB-LTD development in females confer protection or vulnerability to cannabis exposure? Do human adolescent brains show similar sexually dimorphic endocannabinoid trajectories?

Common questions

Read the original research

Sexually Dimorphic Adolescent Trajectories of Prefrontal Endocannabinoid Synaptic Plasticity Equalize in Adulthood, Reflected by Endocannabinoid System Gene Expression.

Cannabis and cannabinoid research, 8(5), 749-767

Citation

Bernabeu, Axel; Bara, Anissa; Murphy Green, Michelle N; Manduca, Antonia; Wager-Miller, Jim; Borsoi, Milene; Lassalle, Olivier; Pelissier-Alicot, Anne-Laure; Chavis, Pascale; Mackie, Ken; Manzoni, Olivier J J. (2023). Sexually Dimorphic Adolescent Trajectories of Prefrontal Endocannabinoid Synaptic Plasticity Equalize in Adulthood, Reflected by Endocannabinoid System Gene Expression.. Cannabis and cannabinoid research, 8(5), 749-767. https://doi.org/10.1089/can.2022.0308

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