Cannabinoid-like Effects Of Five Novel Carboxamide Synthetic Cannabinoids
Figure 1.
Each training session lasted a maximum of 10 min, and the rats could earn up to 20 food pellets. Thirty minutes prior to the training sessions, rats received an injection of either vehicle or Δ9-THC and were subsequently placed in the behavior-testing chambers, where food (45-mg food pellets; Bio-Serve, Frenchtown, NJ) was available as a reinforcer for every ten responses (FR10) on a designated injection appropriate lever. A houselight was centered over the hopper close to the ceiling and was illuminated only when the levers were active. Each dose range included doses that were without effect to those producing at least 50% depression compared to vehicle control. Twenty-four male Sprague-Dawley rats were obtained from Envigo (Houston, TX). Male ND4 Swiss–Webster mice were obtained from Envigo (Houston, TX) at approximately 8 weeks of age and maintained in the University of North Texas Health Science Center (UNTHSC) animal facility for two weeks prior to testin
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
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 5CLADBA 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
Effects of individual doses were compared to the vehicle control value using a priori contrasts. Response-rate data were analyzed by one-way repeated-measure analysis of variance. Percent drug-appropriate responding was shown only if at 5CLADBA least three rats completed the first fixed ratio, whereas all rats are shown for the response rate dat
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
Such decrease remained 2 hr after the administration (Table 4). In locomotor activity, methamphetamine treated group showed approximately 4.2 times increase compared to the negative control treated group. Change of body weight following the treatments with JWH-081 and JWH-210 in mic
4. Drugs
In general, the locomotor depressant and discriminative stimulus effects have been observed at doses that do not produce adverse effects, although tremors were observed upon handling in mice that received JWH-210 (Gatch et al., 2016), and 5F-AMB produced sustained vocalization and convulsions in rats (Gatch et al., 2018). All of the synthetic cannabinoids tested in the present study fully substituted for the discriminative stimulus effects of Δ9-THC. Subsequently, a one-way analysis of variance was conducted on horizontal activity counts for the 30-min period of maximal effect, and planned comparisons were conducted for each dose against the vehicle control using single degree-of-freedom F tests. A two-way analysis of variance, with dose as a between groups factor and time as a within subject factor, was conducted on horizontal activity counts/10 min interval. 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.
Michael B Gatch
Substantial depressant effects were observed within the first 10 min, and maximal depression was observed between 0–30 min following administration. Tremors were observed 30 minutes following 1 mg/kg AMB-FUBINACA in 3 of 8 mice (data not shown). Substantial depressant effects were observed within the first 10 min, and maximal depression was observed between 10–40 min and lasted up to 2.5 to 3 h at the 5CLADBA highest dose tested (0.5 mg/kg).
Figure 1.
There is indication that at least some of the first-generation synthetic cannabinoids act at receptors other than cannabinoid CB1 and CB2 (Wiley et al., 2016), and a compound from the present study, 5F-MDMB-PINACA, was found to activate midbrain dopamine neurons, but not serotonin neurons (Asaoka et al., 2016). As previously mentioned, all of the compounds tested in the present study (MDMB-PINACA, MDMB-CHMICA, MDMB-FUBINACA, ADB-FUBINACA, and AMB-FUBINACA) act as agonists at CB1 receptors (Banister et al., 2015, 2016; Gamage et al., 2018), which suggests these compounds will produce Δ9-THC-like effects, including abuse liability. 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.
Michael B Gat