Persistent exposure to Δ9-Tetrahydrocannabinol during adolescence does not affect nociceptive responding in adult mice

Abstract

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.