| Abuse of products laced with synthetic cannabinoids, like JWH-018 and AM2201, is increasing at an alarming rate. These products are sold as marijuana alternatives and marketed to young teens and first time drug users. Various clinical reports have indicated that use of these synthetic cannabinoid-laced products can cause serious adverse effects like extreme agitation, syncope, tachycardia, chest pain, seizures, and hallucinations. Although very little is known about the metabolism and toxicology of these popular drugs of abuse, mass spectrometric analysis of human urine specimens following JWH-018 and AM2201 exposure identified (o)-, (o-1)-hydroxyl, and (o)-carboxyl derivatives as the major human metabolites, which were excreted as primarily as glucuronic acid conjugates in human urine. The present study extends these initial findings by testing the hypothesis that JWH-018 and its fluorinated analog AM2201 are subject to cytochrome P450-mediated oxidation, forming potent hydroxylated metabolites that retain significant affinity and activity at the cannabinoid 1 (CB1) receptor and that are subsequently conjugated by uridine glucuronosyl transferases (UGTs). Kinetic analysis using recombinant human P450s identified CYP2C9 and -1A2 as major P450s involved in the oxidation of the JWH-018 and AM2201. In vitro studies demonstrated that the primary hydroxylated metabolites produced in humans display high affinity and intrinsic activity at the CB1 receptor, which was attenuated by the CB1 receptor antagonist O-2050. Studies with recombinant UGTs identified UGT1A1, -1A9, -1A10 and -2B7 to be major enzymes involved in the conjugation of the hydroxylated metabolites of JWH-018 and AM2201 with relatively high affinity and high metabolic capacity. Results from the present study provide critical, missing information related to the toxicological consequences of JWH-018 and AM2201 metabolism including mechanism(s) of action at the CB1 receptors. Studies on synthetic cannabinoid metabolites will help future development and validation of a specific assay for synthetic cannabinoid-laced products and will allow scientists to fully explore their toxicological actions. |
