Synthetic cannabinoids are manufactured clandestinely with little quality control and are distributed as herbal "Spice" for smoking or as bulk compound for mixing with a solvent and inhalation via electronic vaporizers. Intoxication with synthetic cannabinoids has been associated with seizure, excited delirium, coma, kidney damage, and other disorders. The chemical alterations produced by heating these structurally novel compounds for consumption are largely unknown. Here we show that heating synthetic cannabinoids containing tetramethylcyclopropyl-ring substituents produced thermal degradants with pharmacological activity that varied considerably from their parent compounds. Moreover, these degradants were formed under conditions simulating smoking. Some products of combustion retained high affinity at the CB1 and CB2 receptors, were more efficacious than CP-55,940 in stimulating CB1-receptor mediated GTPγS binding, and were potent in producing THC-like effects in laboratory animals, while other compounds had low affinity and efficacy and were devoid of cannabimimetic activity. Degradants that retained affinity and efficacy also substituted in drug discrimination tests for the prototypical synthetic cannabinoid JWH-018, and are likely to produce psychotropic effects in humans. Hence, it is important to take into consideration the actual chemical exposures that occur during use of synthetic cannabinoid formulations in order to better comprehend the relationships between dose and effect.
- behavioral pharmacology
- G protein coupled signaling
- G proteins
- structure-activity relationships
- The American Society for Pharmacology and Experimental Therapeutics