A THC-Like Discrimination Cue Did Not Make CP47,497 Equivalent to Marijuana
CP47,497 substituted for THC in a mouse drug-discrimination task, but that result does not mean the compounds have identical effects or human risks. A learned internal drug cue is one pharmacological endpoint.
What substitution meant in this experiment
Mice were trained to respond differently after THC and vehicle. CP47,497 produced responding associated with the THC training condition. This supports a shared component of the interoceptive cue; the animals were not reporting an identical subjective experience.
Other assays supplied different information
Brain-membrane signaling assays compared G-protein activation, while behavioral tests measured movement, temperature, catalepsy and antinociception. Receptor-blocking and knockout experiments supported CB1 mediation. CP47,497 and another synthetic agonist, CP55,940, differed in maximal signaling efficacy, illustrating why synthetic cannabinoids also cannot be treated as one interchangeable chemical.
Adaptation did not erase the differences
Repeated CP47,497 produced tolerance, and prior THC produced cross-tolerance on assessed outcomes. Rimonabant also precipitated withdrawal signs after repeated exposure. Those findings identify shared receptor-related adaptations, rather than demonstrating protection against every synthetic-cannabinoid effect in a person who uses cannabis.
Potency ratios need their original assay
A dose ratio from drug discrimination is not automatically a ratio for toxicity, pain relief or driving effects. Route, dose and endpoint affected the comparisons, and the authors acknowledged imperfect matching of selected doses. These animal and in-vitro results support describing CP47,497 precisely, not labeling it an equivalent marijuana substitute or assigning a human safety margin from the mouse data.
Related analysis: Similar Temperature Tolerance Did Not Make THC and JWH Cannabinoids Interchangeable.
Primary research
Pharmacological characterization of repeated administration of the first generation abused synthetic cannabinoid CP47,497. Journal of basic and clinical physiology and pharmacology (2016). DOI: 10.1515/jbcpp-2015-0118.
