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
§ (3) of the Hungarian act of Forensic Experts (2016.XXIX), the data of the reported case can be utilized freely for scientific and educational purposes without special ethical permission. These results indicate that the simultaneous intoxication of SCRA and ethanol directly and exclusively caused the death of the two victims. The victims did not have any significant diseases that could have contributed to the outcome. Very limited data are available in the scientific literature about the possible effects of the combined consumption of SCRAs and ethanol. Several case reports describe that the presence of a little ng/mL (0.37–4.1) of SCRAs and a high—but not lethal—concentration of ethanol (1.45–2.7 g/L) directly and exclusively contributed to the death of the victim [24–27] (Table 2). The fact that 4F-MDMB-BINACA was not detected in postmortem urine samples is partly explained by the high rate of hepatic metabolism of SCRAs [11, 14, 22], but also suggests that the victims consumed 4F-MDMB-BINACA shortly before their death
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 5CLADBA 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
This might be due to the low activity of numerous metabolizing enzymes resulting in lower drug biotransformation . HepG2 model detected the major ester hydrolysis metabolite of 4F-MDMB-BINACA in abundance but the rest of the metabolites were found in a small amount. Elegans and HLM models detected all of the in-vivo metabolites (100%), whilst HepG2 cells detected 7 out of the 8 in-vivo metabolites (87.5%). Hence, structural elucidation could not be confirmed unless a reference standard is made availabl
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
Although there were reports on the metabolism of 4F-MDMB-BINACA using in-vivo and various in-vitro models, studies were either conducted using small in-vivo sample size such as 1 to 4 samples [5, 29] or in closed environments such as forensic psychiatric wards and prisons . The hepatic cell line HepG2 is often used as an initial screen as it is known to produce high reproducibility results with relatively stable enzyme concentration, although they are limited by the low-level expression of several metabolizing enzymes, including the cytochrome P450 (CYP) class of proteins [17, 18]. In-vitro metabolism studies are generally used to complement these data using perfused organs, tissue or cell cultures and microsomal preparations amongst which pooled human liver microsomes (HLM) have been frequently used to elucidate metabolism of SCBs [12,13,14,15,16]. Since most SCBs are found extensively in metabolized forms in urine, the identification of metabolites is of vital importance for forensic and clinical toxicologists. Identifying SCB intake and its correlating specific adverse effects require rapid elucidation of these SCBs. The proliferation of SCBs has become a global challenge as new compounds are rapidly introduced into the illegal drug market to evade existing drug law
In general, the locomotor depressant and discriminative stimulus effects 5CLADBA 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.
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
§ (3) of the Hungarian act of Forensic Experts (2016.XXIX), the data of the reported case can be utilized freely for scientific and educational purposes without special ethical permission. These results indicate that the simultaneous intoxication of SCRA and ethanol directly and exclusively caused the death of the two victims. The victims did not have any significant diseases that could have contributed to the outcome. Very limited data are available in the scientific literature about the possible effects of the combined consumption of SCRAs and ethanol. Several case reports describe that the presence of a little ng/mL (0.37–4.1) of SCRAs and a high—but not lethal—concentration of ethanol (1.45–2.7 g/L) directly and exclusively contributed to the death of the victim [24–27] (Table 2). The fact that 4F-MDMB-BINACA was not detected in postmortem urine samples is partly explained by the high rate of hepatic metabolism of SCRAs [11, 14, 22], but also suggests that the victims consumed 4F-MDMB-BINACA shortly before their death
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 5CLADBA 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
This might be due to the low activity of numerous metabolizing enzymes resulting in lower drug biotransformation . HepG2 model detected the major ester hydrolysis metabolite of 4F-MDMB-BINACA in abundance but the rest of the metabolites were found in a small amount. Elegans and HLM models detected all of the in-vivo metabolites (100%), whilst HepG2 cells detected 7 out of the 8 in-vivo metabolites (87.5%). Hence, structural elucidation could not be confirmed unless a reference standard is made availabl
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
Although there were reports on the metabolism of 4F-MDMB-BINACA using in-vivo and various in-vitro models, studies were either conducted using small in-vivo sample size such as 1 to 4 samples [5, 29] or in closed environments such as forensic psychiatric wards and prisons . The hepatic cell line HepG2 is often used as an initial screen as it is known to produce high reproducibility results with relatively stable enzyme concentration, although they are limited by the low-level expression of several metabolizing enzymes, including the cytochrome P450 (CYP) class of proteins [17, 18]. In-vitro metabolism studies are generally used to complement these data using perfused organs, tissue or cell cultures and microsomal preparations amongst which pooled human liver microsomes (HLM) have been frequently used to elucidate metabolism of SCBs [12,13,14,15,16]. Since most SCBs are found extensively in metabolized forms in urine, the identification of metabolites is of vital importance for forensic and clinical toxicologists. Identifying SCB intake and its correlating specific adverse effects require rapid elucidation of these SCBs. The proliferation of SCBs has become a global challenge as new compounds are rapidly introduced into the illegal drug market to evade existing drug law
In general, the locomotor depressant and discriminative stimulus effects 5CLADBA 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.
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