Inhalation exposure to smoke from synthetic "marijuana" produces potent cannabimimetic effects in mice

Background: Use of synthetic "marijuana" has increased in recent years, produced adverse effects and prompted the temporary DEA ban of five specific cannabinoid analogs, including JWH-018. The objectives of the current study include determining the chemical content of the herbal product, Buzz, assessing its behavioral effects upon inhalation exposure to mice, determining whether CB(1) receptors mediate its pharmacological activity, and ascertaining its biodisposition in blood and various organs.

Methods: Using a nose-only exposure system, mice were exposed to smoke produced from combustion of an herbal incense product, Buzz, which contained 5.4% JWH-018. Cannabimimetic effects following smoke exposure were evaluated using the tetrad procedure, consisting of the following indices: hypomotility, antinociception, catalepsy, and hypothermia. Additionally, blood and tissues were collected for JWH-018 quantification.

Results: Inhalation exposure to Buzz produced dose-related tetrad effects similar to marijuana as well as dose-related increased levels of JWH-018 in the blood, brain, heart, kidney, liver, lung, and spleen. The behavioral effects were blocked by rimonabant, a CB(1) receptor antagonist. Effects produced by Buzz were similar in magnitude and time-course to those produced by marijuana, though equipotent doses of Buzz and marijuana yielded considerably lower brain levels of JWH-018 than THC for the respective materials.

Conclusions: Inhalation exposure to a product containing JWH-018 penetrates into the brain and other organs and produces CB(1) receptor-mediated behavioral pharmacological effects in mice. The increased potency of JWH-018 compared to THC, the variable amount of drug added to various herbal products, and unknown toxicity, undoubtedly contribute to public health risks of synthetic cannabinoids.