Administration of Δ9-Tetrahydrocannabinol (THC) in Adolescent and Adult Mice

Δ⁹-tetrahydrocannabinol (THC) is responsible for the intoxicating (psychotropic) effects of cannabis and cannabis-derived products currently available in the legal and illegal markets. The psychotropic effects of THC are produced via activation of CB1 cannabinoid receptors in the brain, which are normally engaged by endogenous cannabinoid (endocannabinoid) substances. Outside the brain, THC contributes to the regulation of a wide range of physiological processes by activating CB1 and CB2 receptors. The physiological functions served by endocannabinoid substances and cannabinoid receptors - collectively known as the endocannabinoid system - change considerably throughout the lifespan, with adolescence being a period of heightened sensitivity to the contributions of this signaling complex. This article describes a protocol for preparing THC for parenteral administration and assessing its acute pharmacodynamic effects in mice of both sexes at two developmental stages: adolescence and young adulthood. Focusing on three doses that are widely used in the literature (1, 5, and 10 mg/kg) and the intraperitoneal route, the well-known effects of THC-catalepsy induction, locomotor activity inhibition, and nociception suppression-are illustrated. Moreover, given THC's status as a controlled substance in the United States, the procedures for obtaining and storing it in compliance with current legislation are briefly outlined.