Neurotoxicity Of Synthetic Cannabinoids JWH-081 And JWH-210
To evaluate whether the changes of coordinative functions by CNS damages were due to test substances, rota-rod test was performed using Rota-rod apparatus (Daejong, Seoul, Korea). The test apparatus for the locomotor activity test was designed to measure locomotor activity automatically using UV system (AM 1051, Benwick Electronics, Benwick, UK) when experimental animals moved in the chamber. In both tests, a group of mice were treated with negative control (vehicle, 1 mg/kg, i.p.), positive control (methamphetamine, 1 mg/kg, i.p.), or one of the three doses of test substances (0.1, 1, 5 mg/kg, i.p.) once every other day for 10 day
The current study indicates that the test compounds produce locomotor depression similar to that of Δ9-THC, and fully substitute for the discriminative stimulus effects of Δ9-THC. In summary, these 5F-MDMB-PINACA, MDMB-CHIMICA, MDMB-FUBINACA, ADB-FUBINACA, and AMB-FUBINACA have similar abuse liability as Δ9-tetrahydrocannabinol and should be controlled in a similar fashion. Much of the in vivo click here! testing of the synthetic cannabinoid compounds have been pre-clinical studies focused on their cannabinoid-like effects or like the present study, focused on their abuse liability. 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
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 click here! 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 mic
Some mice showed abnormal behaviors (catalepsy, loss of traction, convulsion) right after the administration of the tested substances. The locomotor activity of the mice was measured 30 min and 2 hrs after the last substance administration. We also examined their neurotoxicity using brain samples through histopathological diagnose, especially in the nucleus accumbens core region. In histopathological analysis, neural cells of the animals treated with the high dose (5 mg/kg) of JWH-081 or JWH-210 showed distorted nuclei and nucleus membranes in the core shell of nucleus accumbens, suggesting neurotoxicity.
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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
