CBD improved memory in adolescent rats that were exposed to THC before birth | Research

The takeaway

CBD given during adolescence rescued cognitive deficits and restored hippocampal plasticity markers in rats that had been prenatally exposed to THC.

Developmental neuroscience researchers, prenatal exposure researchers, CBD pharmacologists

CBD normalized multiple hippocampal plasticity markers disrupted by prenatal THC

What the researchers found

Prenatal THC exposure (2 mg/kg, gestational days 5-20) impaired spatial and configural memory and disrupted hippocampal plasticity markers in adolescent rats. CBD administration (40 mg/kg) before cognitive tasks mitigated impairments in both reward-motivated and aversion-driven memory tests and normalized NMDA receptor subunits, PSD95, Homer 1, and CB1R-related signaling in the hippocampus.

Why it matters

If prenatal THC exposure causes cognitive harm, finding that CBD can rescue those deficits during the adolescent developmental window offers a potential therapeutic approach, though the study also underscores the importance of preventing prenatal exposure.

The numbers in context

THC dose: 2 mg/kg (gestational days 5-20); CBD dose: 40 mg/kg; CBD restored NR1, NR2A NMDA receptor subunits, mGluR5, PSD95, Homer 1, CB1R, and HINT1 mRNA levels

How the study worked

Wistar rats prenatally exposed to THC (2 mg/kg subcutaneously, gestational days 5-20) or vehicle were tested during adolescence using the Can test (reinforcement-motivated) and Barnes maze (aversion-driven). CBD (40 mg/kg i.p.) was administered before testing. Hippocampal markers of excitatory plasticity and endocannabinoid signaling were assessed.

What this study cannot tell us

Animal model with specific doses that may not translate to humans. CBD was given acutely before testing rather than as a chronic treatment. Single THC dose during gestation may not reflect variable human exposure patterns.

How to read the evidence

Well-controlled animal study with multiple cognitive and molecular outcomes, but acute CBD dosing and rat model limit clinical translation.

When this study was published

Published 2023

The bigger picture

Adolescence may represent a critical window for brain reprogramming, where interventions like CBD could potentially address developmental insults. However, preventing prenatal cannabis exposure remains the primary goal.

Questions still open

Would chronic CBD treatment produce more robust cognitive recovery? Do these rescue effects persist into adulthood, or are they limited to the treatment period?

Common questions

Can CBD reverse cognitive effects of prenatal THC exposure?

In this rat study, CBD given during adolescence improved memory performance and restored hippocampal brain markers that had been disrupted by prenatal THC exposure.

What brain changes did prenatal THC cause?

Prenatal THC disrupted NMDA receptor subunits, synaptic scaffold proteins (PSD95, Homer 1), and CB1 receptor signaling in the hippocampus, all of which are important for learning and memory.

Read the original research

CBD enhances the cognitive score of adolescent rats prenatally exposed to THC and fine-tunes relevant effectors of hippocampal plasticity.

Frontiers in pharmacology, 14, 1237485

View on PubMed ↗Publisher’s paper ↗

Citation

Castelli, Valentina; Lavanco, Gianluca; D'Amico, Cesare; Feo, Salvatore; Tringali, Giuseppe; Kuchar, Martin; Cannizzaro, Carla; Brancato, Anna. (2023). CBD enhances the cognitive score of adolescent rats prenatally exposed to THC and fine-tunes relevant effectors of hippocampal plasticity.. Frontiers in pharmacology, 14, 1237485. https://doi.org/10.3389/fphar.2023.1237485