Assessment of pharmacological effects and abuse potential of 5F-EDMB-PICA, CUMYL-PEGACLONE, and NM-2201 in mice.

Rationale: The newly emerging synthetic cannabinoids (SCs) 5F-EDMB-PICA, CUMYL-PEGACLONE, and NM-2201 have been observed to produce effects by activating cannabinoid type 1 (CB1) receptors. Nevertheless, the pharmacological effects and potential for abuse of these three substances remain to be studied. These substances have yet to be regulated in many countries.

Objectives: We investigated the safety, pharmacological effects, rewarding effects, and cannabinoid withdrawal of 5F-EDMB-PICA, CUMYL-PEGACLONE, and NM-2201.

Methods: This study evaluated the drug safety and the cannabinoid-specific pharmacological effects of the three substances through acute toxicity experiments (in which the LD of each substance was obtained) and tetrad experiments (comprising assessments of hypothermia, analgesia, locomotion inhibition, and catalepsy). Furthermore, the conditioned place preference (CPP) experiments and withdrawal experiments were conducted to evaluate the rewarding effect and cannabinoid withdrawal potential of the substances in question.

Results: The results demonstrated that all three drugs exhibited certain acute toxic effects and could potentially induce tetrad effects. The data were analyzed using non-linear regression, and the corresponding ED values and 95% confidence intervals (CI) were obtained. The rank order of potency was determined to be CUMYL-PEGACLONE > 5F-EDMB-PICA > NM-2201. In the CPP experiments, it was demonstrated that 5F-EDMB-PICA significantly induced an increase in CPP score at a dose of 0.3 mg/kg, while NM-2201 caused an increase in CPP score and a significant aversion effect at a dose of 2 and 3 mg/kg, respectively. It is noteworthy that all three types of SCs were observed to produce a significant biphasic effect, indicating that CPP scores were biphasic for all compounds. Following the administration of the CB1 receptor antagonist rimonabant, a notable increase in head twitches and paw tremors was observed, indicating that these three SCs induce cannabinoid withdrawal through the mediation of CB1 receptors.

Conclusions: The results of this study indicated that these SCs possess cannabinoid-specific pharmacological effects and abuse potential, which provides substantial experimental data to support the future regulation of these substances.