A total of 2 and 3 methamphetamine treated mice fell from the spinning rod 30 min and 2 hr after the administration, respectively. After the first injection, 6 mice of the positive control group (methamphetamine, 5 mg/kg, i.p.) showed loss of traction, of which 4 showed tremor. Most of the abnormalities were normalized in synthetic cannabinoid treated mice although those abnormal behaviors remained in methamphetamine treated animals after 2 hr of administration. Brain samples were prepared from the mice after the last administration of test substance
A 30-min period, beginning when maximal depression of locomotor activity first appeared as a function of dose, was used for analysis of dose-response data and calculation of ED50 values. During test sessions, both levers were active, such that ten consecutive responses on either lever led to 4F ADB reinforcement. The substitution tests occurred only if the rats had achieved 85% injection-appropriate responding on the two prior training sessions.
The locomotor activity assay was used to identify approximate time courses and dose ranges of psychoactive effects, which is useful for identifying parameters for drug discrimination experiments and are also predictive of the time course of the psychoactive effects in human users. The purpose of the present study was to assess the abuse liability of 5F-MDMB-PINACA, MDMB-CHIMICA, MDMB-FUBINACA, ADB-FUBINACA, and AMB-FUBINACA. Since there is currently no robust measure of the reinforcing/rewarding effects of cannabinoids, drug discrimination is currently the best model for assessing abuse liability of cannabinoids. The findings produce an apparent paradox, since CPP and self-administration predict with high reliability the likelihood that a compound will be abused by humans, and cannabinoids are well-known to produce active drug-seeking in human
Figure 1.
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
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 4F ADB 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
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 narro
As synthetic cannabinoid receptor agonists (SCRA) are gaining popularity globally, clinicians have to understand that intoxication caused by vaping SCRA is not detected by commonly available tests. He confirmed that he had been vaping an electronic cigarette (e-cigarette) earlier that day just before the onset of his symptoms. Metabolic acidosis (1/3, 0/7) and respiratory acidosis (1/3, 0/7), All 10 patients recovered with supportive care, including intubation and ventilation for one case. In 3 cases ADB-BUTINACA was the only substance detected, while in seven other substances of misuse were also detected including other SCRA, opioids, benzodiazepines cocaine and pregabali
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
A 30-min period, beginning when maximal depression of locomotor activity first appeared as a function of dose, was used for analysis of dose-response data and calculation of ED50 values. During test sessions, both levers were active, such that ten consecutive responses on either lever led to 4F ADB reinforcement. The substitution tests occurred only if the rats had achieved 85% injection-appropriate responding on the two prior training sessions.
The locomotor activity assay was used to identify approximate time courses and dose ranges of psychoactive effects, which is useful for identifying parameters for drug discrimination experiments and are also predictive of the time course of the psychoactive effects in human users. The purpose of the present study was to assess the abuse liability of 5F-MDMB-PINACA, MDMB-CHIMICA, MDMB-FUBINACA, ADB-FUBINACA, and AMB-FUBINACA. Since there is currently no robust measure of the reinforcing/rewarding effects of cannabinoids, drug discrimination is currently the best model for assessing abuse liability of cannabinoids. The findings produce an apparent paradox, since CPP and self-administration predict with high reliability the likelihood that a compound will be abused by humans, and cannabinoids are well-known to produce active drug-seeking in human
Figure 1.
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
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 4F ADB 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
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 narro
As synthetic cannabinoid receptor agonists (SCRA) are gaining popularity globally, clinicians have to understand that intoxication caused by vaping SCRA is not detected by commonly available tests. He confirmed that he had been vaping an electronic cigarette (e-cigarette) earlier that day just before the onset of his symptoms. Metabolic acidosis (1/3, 0/7) and respiratory acidosis (1/3, 0/7), All 10 patients recovered with supportive care, including intubation and ventilation for one case. In 3 cases ADB-BUTINACA was the only substance detected, while in seven other substances of misuse were also detected including other SCRA, opioids, benzodiazepines cocaine and pregabali
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
