Persistent Exposure to Δ9-Tetrahydrocannabinol during Adolescence Does Not Affect Nociceptive Responding in Adult Mice.

Alex Mabou Tagne, Yannick Fotio, Tarif Ibne Rashid, Daniele Piomelli

The Journal of pharmacology and experimental therapeutics 2021 Sep

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Evidence suggests that Δ9-tetrahydrocannabinol (Δ9-THC), the intoxicating component of cannabis, causes enduring changes in the structure and function of adolescent brain circuits implicated in nociceptive responding. However, whether such changes might persistently disrupt nociceptive behaviors remains unknown. In the present study, we subjected C57BL6/J mice of both sexes to once-daily injections of Δ9-THC (5 mg-kg-1, i.p.) or vehicle throughout adolescence (PND 30-43) and, when the animals had reached adulthood (PND 70), assessed nociceptive behavior using the formalin and chronic constriction injury tests. We also investigated, using the tail immersion test, the antinociceptive effects of morphine and the development of tolerance to such effects. The results show that adolescent Δ9-THC exposure does not significantly impair nociceptive responding or morphine-related antinociception and tolerance. The findings suggest that frequent exposure to a moderate dose of Δ9-THC during adolescence does not permanently alter nociceptive circuits in male or female mice. SIGNIFICANCE STATEMENT: The endocannabinoid system serves critical functions in the central and peripheral nervous systems, including regulation of pain, and can be modified by prolonged exposure to the intoxicating constituent of cannabis, Δ9-tetrahydrocannabinol (Δ9-THC). This raises the possibility that regular use of Δ9-THC-containing cannabis during adolescence might cause changes in nociception that persist into adulthood. This study found that frequent early-life exposure to a moderate dose of Δ9-THC does not permanently alter nociceptive function in male or female mice. Copyright © 2021 by The American Society for Pharmacology and Experimental Therapeutics.

Citation

Alex Mabou Tagne, Yannick Fotio, Tarif Ibne Rashid, Daniele Piomelli. Persistent Exposure to Δ9-Tetrahydrocannabinol during Adolescence Does Not Affect Nociceptive Responding in Adult Mice. The Journal of pharmacology and experimental therapeutics. 2021 Sep;378(3):215-221