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
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 powder showed distorted nuclei and nucleus membranes in the core shell of nucleus accumbens, suggesting neurotoxicity.
Table of Conten
Morris water maze test was performed to evaluate the changes in learning and memory function. Only a few case reports about the dangers of some synthetic cannabinoids due to neurotoxicity have been published (Cohen et al., 2012; McGuinness et al., 2012; Harris and Brown, 2013; Hermanns et al., 2013). In addition, the lack of information about neurotoxicity of synthetic cannabinoids could allow abusers consume those substances undiscerningly. However, slight structural changes might cause biochemical properties including dependence liability and neurotoxicity. The substances used in the present study both possess naphthoylindole moiety as their parental structure. (B) The ratio of damaged cells containing pyknotic or condensed nuclei and low hematoxilin affinity to total cells were calculated in nucleus accumben
One recent study has looked at other mechanisms of action in some of the older synthetic cannabinoids and reported that some produced varying amounts of activity at sites which are related to cardiotoxicity and heart disease (Wiley et al., 2016
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 laws.
Fig.
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
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 powder showed distorted nuclei and nucleus membranes in the core shell of nucleus accumbens, suggesting neurotoxicity.
Table of Conten
Morris water maze test was performed to evaluate the changes in learning and memory function. Only a few case reports about the dangers of some synthetic cannabinoids due to neurotoxicity have been published (Cohen et al., 2012; McGuinness et al., 2012; Harris and Brown, 2013; Hermanns et al., 2013). In addition, the lack of information about neurotoxicity of synthetic cannabinoids could allow abusers consume those substances undiscerningly. However, slight structural changes might cause biochemical properties including dependence liability and neurotoxicity. The substances used in the present study both possess naphthoylindole moiety as their parental structure. (B) The ratio of damaged cells containing pyknotic or condensed nuclei and low hematoxilin affinity to total cells were calculated in nucleus accumben
One recent study has looked at other mechanisms of action in some of the older synthetic cannabinoids and reported that some produced varying amounts of activity at sites which are related to cardiotoxicity and heart disease (Wiley et al., 2016
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 laws.
Fig.
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