All of the compounds tested in the present study depressed locomotor activity as is typical for other synthetic cannabinoids (see review by Wiley et al., 2017). Average horizontal activity counts/10 min as a function of time (10 min bins) and dose. Depressant effects of 1.33 mg/kg were observed within 10 min following administration and peak depressant effects were JWH-210 powder observed between 0–30 min. Duration of the locomotor depression increased over dose from 30 min following 0.1 mg/kg to 2.5 h following 1 mg/k
These synthetic cannabinoids act directly at cannabinoid CB1 and CB2 receptors as does Δ9-tetrahydrocannabinol (Δ9-THC) found in marijuana, but have different chemical structures unrelated to Δ9-THC, different metabolism, and often greater toxicity (Fantegrossi et al., 2014). Discriminative stimulus effects were tested in rats trained to discriminate Δ9-tetrahydrocannabinol (3 mg/kg, 30-min pretreatment). 5F-MDMB-PINACA (also known as 5F-ADB, 5F-ADB-PINACA), MDMB-CHIMICA, MDMB-FUBINACA, ADB-FUBINACA, and AMB-FUBINACA (also known as FUB-AMB, MMB-FUBINACA) were tested for in vivo cannabinoid-like effects to assess their abuse liabilit
Tremors were observed in mice 30 minutes following 1 mg/kg AMB-FUBINACA in the present study. Pretreatment times and dose ranges for the drug discrimination assay were selected based on the time of peak depression in the locomotor activity assay in mice. Average potency of the discriminative stimulus effects of early compounds was 0.81±0.17 mg/kg (Gatch et al., 2014), whereas the potency of a recent set was 0.09±0.03 mg/kg (Gatch et al., 2018), and the potency of the current set is 0.05±0.01 mg/kg. Short-onset, short-acting compounds have a greater abuse liability, and long-acting compounds pose problems of long-acting adverse effects and interactions with other drugs. The duration of action of the synthetic cannabinoids tested using the 8-h protocol have varied widely, with some producing a duration of action no longer than 1 h, others producing a duration of action between 1–2 h, and others lasting more than 2 h. There seems to be a trend of newer synthetic cannabinoids being more potent than earlier compound
After the incubation, mixture was centrifuged (18,000 x g, 20 °C) for 5 min and 0.5 μL of the supernatant was directly injected to the chromatographic system. In the next step, ammonium formate as salting agent was added to the mixture and incubated in a thermomixer (20 °C, 1200 rpm) for 15 min. After vortex-mixing, the mixture was allowed to stand
JWH-210 powder at room temperature for 5 min. MS/MS experiments were performed in MRM (multiple reaction monitoring) mode with an isolation window of 0.4 m/z. The MS measurement was performed in positive ion mode (except for some acidic compounds such as barbiturates
Synthetic cannabinoids have consistently been shown to produce discriminative stimulus effects similar to those JWH-210 powder of Δ9-THC (Bannister and Connor, 2018), and MDMB-FUBINACA fully substituted for Δ9-THC (Gamage et al., 2018). The chemical structures of the recent synthetic cannabinoids are unlike that of Δ9-THC, but are largely based on the structure of older synthetic cannabinoids that are known to have substantial abuse liability (Fig. 1). All 5 compounds decreased locomotor activity and produced discriminative stimulus effects similar to those of Δ9-THC, which suggests they may have abuse liability similar to that of Δ9-THC. Subsequent testing identified 5F-ADB to have been present in a total of ten people who had died from unexplained drug overdoses in Japan between September 2014 and December 2014. AMB-FUBINACA produced tremors and may be of increased risk in human recreational users.
Michael B Gatch
These findings are in agreement with earlier studies showing the synthetic cannabinoids substitute for the discriminative stimulus effects of Δ9-THC (see review by Wiley et al., 2017). Pretreatment times and dose ranges for the drug discrimination assay were selected based on the time of peak depression in the locomotor activity assay in mice. As mentioned previously, short-onset compounds have a greater abuse liability; further, compounds that have fewer adverse effects while they are active are likely to be preferred. All five of the compounds in the present study fully substituted with a pretreatment time of 15 min, suggesting a rapid onset of the discriminative stimulus effects. All of the cathinones fully substituted for the discriminative stimulus effects of Δ9-tetrahydrocannabinol (≥80% drug-appropriate responding). Because response suppression may compromise stimulus control, rats failing to complete at least ten responses during the test session were excluded from the analysis of the discriminative stimulus effects of that dose of test compoun
Locomotor activity in mice was tested to screen for locomotor depressant effects and to identify behaviorally-active dose ranges and times of peak effect. Previous studies have demonstrated that these compounds have chemical structures similar to synthetic cannabinoids known to have substantial abuse liability and act at the CB1 receptor. Tremors were not observed following AMB-FUBINACA during the drug discrimination study, but the maximum dose tested was only 0.1 mg/kg, which is 10-fold lower than the dose that produced tremors in the mice. AMB-FUBINACA has been implicated in severe adverse effects in recreational users (Adams et al., 2017; Hamilton et al., 2017), which suggests that the range between behaviorally active and toxic doses of AMB-FUBINACA is narrow. Following that line of reasoning, it should also be noted that some of the more recent compounds produced non-linear dose-effect curves and one compound produced an inverted U-shaped dose-effect, such that intermediate dose fully substituted, but higher doses did not (Gatch and Forster, 2018). All of the compounds identified as available on the recreational market and submitted to our laboratory by the US Drug Enforcement Agency for testing have fully substituted at some dose (Gatch and Forster 2014, 2015, 2016, 2018); however; it is important to note that not all structural congeners are active (Wiley et al., 2012