Adverse Effects of Synthetic Cannabinoids: Management of Acute Toxicity and Withdrawal

Acute and subacute toxic effects of CUMYL-4CN-BINACA on male albino rats

PURPOSE

There is very little information about the toxicological and pathological effects of synthetic cannabinoids, which have cannabis-like properties. This study was carried out to histopathologically, hematologically, and biochemically determine the toxic effects of acute and subacute exposure to a novel synthetic cannabinoid 1-(4-cyanobutyl)-N-(2-phenylpropan-2-yl)indazole-3-carboxamide in internal organs of adult male rats.

METHODS

The cannabinoid was injected intraperitoneally at three doses (0.5, 1.0, and 2.0 mg/kg, body weight). The cannabinoid was administered to acute groups for 2 days and to subacute groups for 14 days. Observations were made for 14 days and various changes such as mortality, injury, and illness were recorded daily. Hematological and biochemical changes were evaluated and histopathological analyses in lung, liver, and kidney tissues were also performed.

RESULTS

No mortality was observed. It was observed that there were fluctuations in hematological and serum biochemical parameters. Among the oxidative stress parameters, significant decreases in superoxide dismutase, catalase levels and significant increases in lipid peroxidation levels were determined. Serious pathological changes such as necrosis, vacuolation, congestion, and fibrosis were observed in the internal organs in a dose-dependent and time-dependent manner. It was also found that the synthetic cannabinoid triggered apoptosis in the organs. The results demonstrated that the most affected organ by the cannabinoid was the kidney.

CONCLUSION

This study showed for the first time that CUMYL-4CN-BINACA adversely affects healthy male albino rats. It can be estimated that the abuse of the cannabinoid may harm human health in the same way.

Sex-specific behavioural, metabolic, and immunohistochemical changes after repeated administration of the synthetic cannabinoid AKB48 in mice

BACKGROUND AND PURPOSE

AKB48 is a synthetic cannabinoid illegally sold for its psychoactive cannabis-like effects that have been associated with acute intoxication and whose effects are poorly known.

EXPERIMENTAL APPROACH

Using a behavioural, neurochemical, and immunohistochemical approach, we investigated the pharmaco-toxicological effects, pharmacokinetics, and neuroplasticity at cannabinoid CB1 receptors in the cerebellum and cortex induced by repeated AKB48 administration in male and female mice.

KEY RESULTS

The effects of AKB48 varied significantly depending on sex and treatment duration. The first injection impaired sensorimotor responses and reduced body temperature, analgesia, and breath rate to a greater extent in females than in males; the second injection induced stronger effects in males while the third injection of AKB48 induced weaker responses in both sexes, suggesting emergence of tolerance. The CB1 receptor antagonist NESS-0327 prevented the effects induced by repeated AKB48, confirming a CB1 receptor-mediated action. Blood AKB48 levels were higher in females than in males and repeated administration caused a progressive rise of AKB48 levels in both sexes, suggesting an inhibitory effect on cytochrome activity. Finally, immunohistochemical analysis revealed higher expression of CB1 receptors in the cerebellum and cortex of females, and a rapid CB1 receptor down-regulation in cerebellar and cortical areas following repeated AKB48 injections, with neuroadaptation occurring generally more rapidly in females than in males.

CONCLUSION AND IMPLICATIONS

We have shown for the first time that AKB48 effects significantly vary with prolonged use and that sex affects the pharmacodynamic/pharmacokinetic responses to repeated administration, suggesting a sex-tailored approach in managing AKB48-induced intoxication.

Cannabis use in liver transplant candidates and recipients

The increasing legality and acceptance of cannabis sale and consumption across the United States has led to a measurable increase in cannabis use nationwide, including in liver transplant (LT) candidates and recipients. With over 75% of liver transplant recipients transplanted in states with legalized use of medicinal and/or recreational cannabis, liver transplant clinicians must have expertise in the assessment of cannabis use given its potential impact on clinical care. In this review, the authors provide an understanding of nomenclature and tools to assess cannabis use, highlight essential components to guide clinical policy development and implementation, and discuss the potential impacts of cannabis use on patients' transplant course.

Cannabis use in the United States and its impact on gastrointestinal health

In recent years, the legalization and social acceptability of cannabis use have increased in the United States. Concurrently, the prevalence of cannabis use has continued to rise, and cannabis products have diversified. There are growing concerns regarding the health effects of regular and high-potency cannabis use, and new research has shed light on its potentially negative effects. Here, we review evidence of the gastrointestinal (GI) effects of cannabis and cannabinoids. Dysregulation of the endocannabinoid system might contribute to various GI disorders, including irritable bowel syndrome and cyclic vomiting syndrome, and endocannabinoids have been found to regulate visceral sensation, nausea, vomiting, and the gut microbiome. Cannabis has been shown to have antiemetic properties, and the US Food and Drug Administration has approved cannabis-based medications for treating chemotherapy-induced nausea and vomiting. Yet, chronic heavy cannabis use has been linked to recurrent episodes of severe nausea and intractable vomiting (cannabinoid hyperemesis syndrome). Given the considerable heterogeneity in the scientific literature, it is unclear if cannabinoid hyperemesis syndrome is truly a distinct entity or a subtype of cyclic vomiting that is unmasked by heavy cannabis use and the associated dysregulation of the endocannabinoid system. The changes in cannabis legalization, availability, and public risk perceptions have outpaced research in this area and there is a need for robust, prospective, large-scale studies to understand the effects of cannabis use on GI health.

Product labeling accuracy and contamination analysis of commercially available cannabidiol product samples

Background and objective: Commercially available cannabidiol (CBD) products are increasingly being used for medicinal purposes, including for the treatment of various neurological conditions, but there are growing concerns around adherence to quality control measures that protect consumers. This study was conducted to assess the purity and label accuracy of commercially available CBD products. Methods: Commercially available CBD products were chosen from the open stream of commerce in the United States based on formulations as a tincture, gummy, vape, or topical product. Cannabinoid concentrations were analyzed to verify label accuracy including "full spectrum," "broad spectrum," and "CBD isolate" claims on the product label. Analysis for the presence of contaminants included evaluation for heavy metals, pesticides, and residual solvents. Labeled and actual total amounts of CBD and levels of impurities such as heavy metals, residual solvents, and pesticides were measured. Results: A total of 202 CBD products (100 tinctures, 48 gummies, 34 vape products, and 20 topicals) were chosen to represent a broad sample in the United States. Of the products tested (full spectrum, n = 84; broad spectrum, n = 28; CBD isolate, n = 37), 26% did not meet the definition for product type claimed on the packaging. The majority of products (74%) deviated from their label claim of CBD potency by at least 10%. Heavy metals were detected 52 times across 44 of the 202 products tested, with lead being the most prevalent heavy metal. Residual solvents were detected 446 times across 181 of 202 products, with the highest concentrations reported for hexane, m/p-xylene, methanol, and o-xylene. Of 232 pesticides tested, 26 were found 55 times across 30 products. A total of 3% of heavy metals, 1% of residual solvents, and 1% of pesticides violated >1 regulatory threshold. Discussion: This study demonstrated that the majority of commercially available CBD products tested within the current study are inaccurately labeled. Heavy metals, residual solvents, and pesticides were found in several products, some of which violated regulatory thresholds. Thus, uniform compliance with CBD quality control measures is lacking and raises consumer protection concerns. Improved regulatory oversight of this industry is recommended.

In-silico identification and exploration of small molecule coumarin-1,2,3-triazole hybrids as potential EGFR inhibitors for targeting lung cancer

Globally, lung cancer is a significant public health concern due to its role as the leading cause of cancer-related mortalities. The promising target of EGFR for lung cancer treatment has been identified, providing a potential avenue for more effective therapies. The purpose of the study was to design a library of 1843 coumarin-1,2,3-triazole hybrids and screen them based on a designed pharmacophore to identify potential inhibitors targeting EGFR in lung cancer with minimum or no side effects. Pharmacophore-based screening was carried out and 60 hits were obtained. To gain a better understanding of the binding interactions between the compounds and the targeted receptor, molecular docking was conducted on the 60 screened compounds. In-silico ADME and toxicity studies were also conducted to assess the drug-likeness and safety of the identified compounds. The results indicated that coumarin-1,2,3-triazole hybrids COUM-0849, COUM-0935, COUM-0414, COUM-1335, COUM-0276, and COUM-0484 exhibit dock score of - 10.2, - 10.2, - 10.1, - 10.1, - 10, - 10 while reference molecule - 7.9 kcal/mol for EGFR (PDB ID: 4HJO) respectively. The molecular docking and molecular dynamics simulations revealed that the identified compounds formed stable interactions with the active site of EGFR, indicating their potential as inhibitors. The in-silico ADME and toxicity studies showed that the compounds had favorable drug-likeness properties and low toxicity, further supporting their potential as therapeutic agents. Finally, we performed DFT studies on the best-selected ligands to gain further insights into their electronic properties. The findings of this study provide important insights into the potential of coumarin-1,2,3-triazole hybrids as promising EGFR inhibitors for the management of lung cancer.

Somatic and anxiety-like behaviors in male and female rats during withdrawal from the non-selective cannabinoid agonist WIN 55,212-2

Synthetic cannabinoids are associated with higher risk of dependence and more intense withdrawal symptoms than plant-derived Δ9-tetrahydrocannabinol (THC). Avoidance of withdrawal symptoms, including anxiogenic effects, can contribute to continued cannabinoid use. Adult male and female Long-Evans rats were given escalating doses of WIN 55,212-2 (WIN) via twice daily intrajugular infusions. Precipitated withdrawal was elicited with SR 141716 (rimonabant) 4 h after the final infusion. Global withdrawal scores (GWS) were compiled by summing z-scores of observed somatic behaviors over a 30-min period with locomotor activity simultaneously collected via beam breaks. Rimonabant precipitated withdrawal in female and male rats at 3 or 10 mg/kg, respectively, but the individual behaviors contributing to GWS were not identical. 3 mg/kg rimonabant did not impact locomotor behavior in females, but 10 mg/kg decreased locomotion in male controls. Spontaneous withdrawal observed between 6 and 96 h after the final infusion was quantifiable up to 24 h following WIN administration. Individual behaviors contributing to GWS varied by sex and time point. Males undergoing spontaneous withdrawal engaged in more locomotion than females undergoing withdrawal. Separate groups of rats were subjected to a battery of anxiety-like behavioral tests (elevated plus maze, open field test, and marble burying test) one or two weeks after WIN or vehicle infusions. At one week abstinence, sex-related effects were noted in marble burying and the open field test but were unrelated to drug treatment. At two weeks abstinence, females undergoing withdrawal spent more time grooming during marble burying and performed more marble manipulations than their male counterparts. WIN infusions did not impact estrous cycling, and GWS scores were not correlated with estrous at withdrawal. Collectively, these results show qualitative sex differences in behaviors contributing to the behavioral experience of cannabinoid withdrawal supporting clinical findings from THC.

Tetrahydrocannabinol and Cannabidiol for Pain Treatment-An Update on the Evidence

In light of the current International Association for the Study of Pain (IASP) clinical practice guidelines (CPGs) and the European Society for Medical Oncology (ESMO) guidelines, the topic of cannabinoids in relation to pain remains controversial, with insufficient research presently available. Cannabinoids are an attractive pain management option due to their synergistic effects when administered with opioids, thereby also limiting the extent of respiratory depression. On their own, however, cannabinoids have been shown to have the potential to relieve specific subtypes of chronic pain in adults, although controversies remain. Among these subtypes are neuropathic, musculoskeletal, cancer, and geriatric pain. Another interesting feature is their effectiveness in chemotherapy-induced peripheral neuropathy (CIPN). Analgesic benefits are hypothesized to extend to HIV-associated neuropathic pain, as well as to lower back pain in the elderly. The aim of this article is to provide an up-to-date review of the existing preclinical as well as clinical studies, along with relevant systematic reviews addressing the roles of various types of cannabinoids in neuropathic pain settings. The impact of cannabinoids in chronic cancer pain and in non-cancer conditions, such as multiple sclerosis and headaches, are all discussed, as well as novel techniques of administration and relevant mechanisms of action.

Cognitive dysfunction and impaired neuroplasticity following repeated exposure to the synthetic cannabinoid JWH-018 in male mice

BACKGROUND AND PURPOSE

Psychotic disorders have been reported in long-term users of synthetic cannabinoids. This study aims at investigating the long-lasting effects of repeated JWH-018 exposure.

EXPERIMENTAL APPROACH

Male CD-1 mice were injected with vehicle, JWH-018 (6 mg·kg-1 ), the CB1 -antagonist NESS-0327 (1 mg·kg-1 ) or co-administration of NESS-0327 and JWH-018, every day for 7 days. After 15 or 16 days washout, we investigated the effects of JWH-018 on motor function, memory, social dominance and prepulse inhibition (PPI). We also evaluated glutamate levels in dialysates from dorsal striatum, striatal dopamine content and striatal/hippocampal neuroplasticity focusing on the NMDA receptor complex and the neurotrophin BDNF. These measurements were accompanied by in vitro electrophysiological evaluations in hippocampal preparations. Finally, we investigated the density of CB1 receptors and levels of the endocannabinoid anandamide (AEA) and 2-arachidonoylglycerol (2-AG) and their main synthetic and degrading enzymes in the striatum and hippocampus.

KEY RESULTS

The repeated treatment with JWH-018 induced psychomotor agitation while reducing social dominance, recognition memory and PPI in mice. JWH-018 disrupted hippocampal LTP and decreased BDNF expression, reduced the synaptic levels of NMDA receptor subunits and decreased the expression of PSD95. Repeated exposure to JWH-018, reduced hippocampal CB1 receptor density and induced a long-term alteration in AEA and 2-AG levels and their degrading enzymes, FAAH and MAGL, in the striatum.

CONCLUSION AND IMPLICATIONS

Our findings suggest that repeated administration of a high dose of JWH-018 leads to the manifestation of psychotic-like symptoms accompanied by alterations in neuroplasticity and change in the endocannabinoid system.

Acute intoxication caused by three common synthetic cannabinoids: The experience of a large, urban, tertiary care hospital

BACKGROUND

Synthetic cannabinoids (SC) are chemical substances, which activate cannabinoid receptors in a similar fashion to tetrahydrocannabinol, but with increased efficacy, and are used as illicit recreational drugs.

OBJECTIVE

Our objective was to characterize the clinical manifestations and management of three specific, common SC exposures in a cohort of patients presenting to the emergency department of our institution.

METHODS

Retrospective case series of patients admitted to an urban tertiary care center between August 1, 2018 and December 31, 2021, with confirmed SC use and positive urinary immunoassay testing for AB-FUBINACA, 4F-MDMB-BUTINACA and ACHMINACA.

RESULTS

58 patients met inclusion criteria during the 3-year study period; median age was 35 years, 60% were male, 31% patients were exposed to >1 substance, and 31% needed hospital addition. The most common physical signs were cardiovascular (54%) and neuropsychiatric (45%). Severe outcomes included coma and seizures, necessitating intubation in 4 patients, and acute renal injury in 7 patients.

CONCLUSION

SC are potentially harmful drugs of abuse which can lead to life-threatening complications. Acute care personnel should be aware of the broad range of signs and symptoms of SC use. Testing with short turn around times is available to assess SC use.

In-silico design, pharmacophore-based screening, and molecular docking studies reveal that benzimidazole-1,2,3-triazole hybrids as novel EGFR inhibitors targeting lung cancer

Lung cancer is a complex and heterogeneous disease, which has been associated with various molecular alterations, including the overexpression and mutations of the epidermal growth factor receptor (EGFR). In this study, designed a library of 1843 benzimidazole-1,2,3-triazole hybrids and carried out pharmacophore-based screening to identify potential EGFR inhibitors. The 164 compounds were further evaluated using molecular docking and molecular dynamics simulations to understand the binding interactions between the compounds and the receptor. In-si-lico ADME and toxicity studies were also conducted to assess the drug-likeness and safety of the identified compounds. The results of this study indicate that benzimidazole-1,2,3-triazole hybrids BENZI-0660, BENZI-0125, BENZI-0279, BENZI-0415, BENZI-0437, and BENZI-1110 exhibit dock scores of -9.7, -9.6, -9.6, -9.6, -9.6, -9.6 while referencing molecule -7.9 kcal/mol for EGFR (PDB ID: 4HJO), respectively. The molecular docking and molecular dynamics simulations revealed that the identified compounds formed stable interactions with the active site of EGFR, indicating their potential as inhibitors. The in-silico ADME and toxicity studies showed that the compounds had favorable drug-likeness properties and low toxicity, further supporting their potential as therapeutic agents. Finally, performed DFT studies on the best-selected ligands to gain further insights into their electronic properties. The findings of this study provide important insights into the potential of benzimidazole-1,2,3-triazole hybrids as promising EGFR inhibitors for the treatment of lung cancer. This research opens up a new avenue for the discovery and development of potent and selective EGFR inhibitors for the treatment of lung cancer.Communicated by Ramaswamy H. Sarma.

Potential neonatal toxicity of new psychoactive substances

Cannabis, cocaine, 3,4-methylenedioxymethamphetamine, and lysergic acid diethylamide are psychoactive substances with a significant increase in consumption during the 21st century due to their popularity in medicinal and recreational use. New psychoactive substances (NPSs) mimic established psychoactive substances. NPSs are known as being natural and safe to consumers; however, they are neither natural nor safe, causing severe adverse reactions, including seizures, nephrotoxicity, and sometimes death. Synthetic cannabinoids, synthetic cathinones, phenethylamines, and piperazines are all examples of NPSs. As of January 2020, nearly 1000 NPSs have become documented. Due to their low cost, ease of availability, and difficulty of detection, misuse of NPSs has become a familiar and growing problem, especially in adolescents and young adults in the past decade. The use of NPSs is associated with higher risks of unplanned sexual intercourse and pregnancy. As many as 4 in 100 women seeking treatment for substance abuse are pregnant or nursing. Animal studies and human clinical case reports have shown that exposure to certain NPSs during lactation periods has toxic effects on neonates, increasing various risks, including brain damage. Nevertheless, neonatal toxicity effects of NPSs are usually unrecognized and overlooked by healthcare professionals. In this review article, we introduce and discuss the potential neonatal toxicity of NPSs, emphasizing synthetic cannabinoids. Utilizing the established prediction models, we identify synthetic cannabinoids and their highly accumulative metabolites in breast milk.

Mechanisms of cannabinoid tolerance

Cannabis has been used recreationally and medically for centuries, yet research into understanding the mechanisms of its therapeutic effects has only recently garnered more attention. There is evidence to support the use of cannabinoids for the treatment of chronic pain, muscle spasticity, nausea and vomiting due to chemotherapy, improving weight gain in HIV-related cachexia, emesis, sleep disorders, managing symptoms in Tourette syndrome, and patient-reported muscle spasticity from multiple sclerosis. However, tolerance and the risk for cannabis use disorder are two significant disadvantages for cannabinoid-based therapies in humans. Recent work has revealed prominent sex differences in the acute response and tolerance to cannabinoids in both humans and animal models. This review will discuss evidence demonstrating cannabinoid tolerance in rodents, non-human primates, and humans and our current understanding of the neuroadaptations occurring at the cannabinoid type 1 receptor (CB1R) that are responsible tolerance. CB1R expression is downregulated in tolerant animals and humans while there is strong evidence of CB1R desensitization in cannabinoid tolerant rodent models. Throughout the review, critical knowledge gaps are indicated and discussed, such as the lack of a neuroimaging probe to assess CB1R desensitization in humans. The review discusses the intracellular signaling pathways that are responsible for mediating CB1R desensitization and downregulation including the action of G protein-coupled receptor kinases, β-arrestin2 recruitment, c-Jun N-terminal kinases, protein kinase A, and the intracellular trafficking of CB1R. Finally, the review discusses approaches to reduce cannabinoid tolerance in humans based on our current understanding of the neuroadaptations and mechanisms responsible for this process.

Structural basis for activation of CB1 by an endocannabinoid analog

Endocannabinoids (eCBs) are endogenous ligands of the cannabinoid receptor 1 (CB1), a G protein-coupled receptor that regulates a number of therapeutically relevant physiological responses. Hence, understanding the structural and functional consequences of eCB-CB1 interactions has important implications for designing effective drugs targeting this receptor. To characterize the molecular details of eCB interaction with CB1, we utilized AMG315, an analog of the eCB anandamide to determine the structure of the AMG315-bound CB1 signaling complex. Compared to previous structures, the ligand binding pocket shows some differences. Using docking, molecular dynamics simulations, and signaling assays we investigated the functional consequences of ligand interactions with the "toggle switch" residues F2003.36 and W3566.48. Further, we show that ligand-TM2 interactions drive changes to residues on the intracellular side of TM2 and are a determinant of efficacy in activating G protein. These intracellular TM2 rearrangements are unique to CB1 and are exploited by a CB1-specific allosteric modulator.

Acute Cardiovascular and Cardiorespiratory Effects of JWH-018 in Awake and Freely Moving Mice: Mechanism of Action and Possible Antidotal Interventions?

JWH-018 is the most known compound among synthetic cannabinoids (SCs) used for their psychoactive effects. SCs-based products are responsible for several intoxications in humans. Cardiac toxicity is among the main side effects observed in emergency departments: SCs intake induces harmful effects such as hypertension, tachycardia, chest pain, arrhythmias, myocardial infarction, breathing impairment, and dyspnea. This study aims to investigate how cardio-respiratory and vascular JWH-018 (6 mg/kg) responses can be modulated by antidotes already in clinical use. The tested antidotes are amiodarone (5 mg/kg), atropine (5 mg/kg), nifedipine (1 mg/kg), and propranolol (2 mg/kg). The detection of heart rate, breath rate, arterial oxygen saturation (SpO2), and pulse distention are provided by a non-invasive apparatus (Mouse Ox Plus) in awake and freely moving CD-1 male mice. Tachyarrhythmia events are also evaluated. Results show that while all tested antidotes reduce tachycardia and tachyarrhythmic events and improve breathing functions, only atropine completely reverts the heart rate and pulse distension. These data may suggest that cardiorespiratory mechanisms of JWH-018-induced tachyarrhythmia involve sympathetic, cholinergic, and ion channel modulation. Current findings also provide valuable impetus to identify potential antidotal intervention to support physicians in the treatment of intoxicated patients in emergency clinical settings.

Untargeted metabolomics analysis assisted by signal selection for comprehensively identifying metabolites of new psychoactive substances: 4-MeO-α-PVP as an example

New psychoactive substances (NPS) have been rapidly emerged as legal alternatives to controlled drugs, which raised severe public health issue. The detection and monitoring of its intake by complete metabolic profiling is an urgent and vital task. Untargeted metabolomics approach has been applied for several NPS metabolites studies. Although the number of such works is relatively limited but with a rapidly growing need. The present study aimed to propose a procedure that includes liquid chromatography high-resolution mass spectrometry (LC-HRMS) analysis and a signal selection software, MetaboFinder, programed as a web tool. The comprehensive metabolites profile of one kind of NPS, 4-methoxy-α-pyrrolidinovalerophenone (4-MeO-α-PVP), was studied by using this workflow. In this study, two different concentrations of 4-MeO-α-PVP along with as blank sample were incubated with human liver S9 fraction for the conversion to their metabolites and followed by LC-MS analysis. After retention time alignment and feature identification, 4640 features were obtained and submitted to statistical analysis for signal selection by using MetaboFinder. A total of 50 features were considered as 4-MeO-α-PVP metabolite candidates showing significant changes (p < 0.00001 and fold change >2) between the two investigated groups. Targeted LC-MS/MS analysis was conducted focusing on these significantly expressed features. Assisted by chemical formula determination according to high mass accuracy and in silico MS2 fragmentation prediction, 19 chemical structure identifications were achieved. Among which, 8 metabolites have been reported derived from 4-MeO-α-PVP in a previous literature while 11 novel 4-MeO-α-PVP metabolites were identified by using our strategy. Further in vivo animal experiment confirmed that 18 compounds were 4-MeO-α-PVP metabolites, which demonstrated the feasibility of our strategy for screening the 4-MeO-α-PVP metabolites. We anticipate that this procedure may support and facilitate traditional metabolism studies and potentially being applied for routine NPS metabolites screening.

Synthetic Cannabinoids: A Pharmacological and Toxicological Overview

Synthetic cannabinoids (SCs) are a chemically diverse group of new psychoactive substances (NPSs) that target the endocannabinoid system, triggering a plethora of actions (e.g., elevated mood sensation, relaxation, appetite stimulation) that resemble, but are more intense than, those induced by cannabis. Although some of these effects have been explored for therapeutic applications, anticipated stronger psychoactive effects than cannabis and reduced risk perception have increased the recreational use of SCs, which have dominated the NPS market in the United States and Europe over the past decade. However, rising SC-related intoxications and deaths represent a major public health concern and embody a major challenge for policy makers. Here, we review the pharmacology and toxicology of SCs. A thorough characterization of SCs' pharmacodynamics and toxicodynamics is important to better understand the main mechanisms underlying acute and chronic effects of SCs, interpret the clinical/pathological findings related to SC use, and improve SC risk awareness.

The Old and the New: Cardiovascular and Respiratory Alterations Induced by Acute JWH-018 Administration Compared to Δ9-THC-A Preclinical Study in Mice

Several new psychoactive substances (NPS) are responsible for intoxication involving the cardiovascular and respiratory systems. Among NPS, synthetic cannabinoids (SCs) provoked side effects in humans characterized by tachycardia, arrhythmias, hypertension, breathing difficulty, apnoea, myocardial infarction, and cardiac arrest. Therefore, the present study investigated the cardio-respiratory (MouseOx Plus; EMKA electrocardiogram (ECG) and plethysmography TUNNEL systems) and vascular (BP-2000 systems) effects induced by 1-naphthalenyl (1-pentyl-1H-indol-3-yl)-methanone (JWH-018; 0.3-3-6 mg/kg) and Δ⁹-tetrahydrocannabinol (Δ⁹-THC; 0.3-3-6 mg/kg), administered in awake CD-1 male mice. The results showed that higher doses of JWH-018 (3-6 mg/kg) induced deep and long-lasting bradycardia, alternated with bradyarrhythmia, spaced out by sudden episodes of tachyarrhythmias (6 mg/kg), and characterized by ECG electrical parameters changes, sustained bradypnea, and systolic and transient diastolic hypertension. Otherwise, Δ⁹-THC provoked delayed bradycardia (minor intensity tachyarrhythmias episodes) and bradypnea, also causing a transient and mild hypertensive effect at the tested dose range. These effects were prevented by both treatment with selective CB₁ (AM 251, 6 mg/kg) and CB₂ (AM 630, 6 mg/kg) receptor antagonists and with the mixture of the antagonists AM 251 and AM 630, even if in a different manner. Cardio-respiratory and vascular symptoms could be induced by peripheral and central CB₁ and CB₂ receptors stimulation, which could lead to both sympathetic and parasympathetic systems activation. These findings may represent a starting point for necessary future studies aimed at exploring the proper antidotal therapy to be used in SCs-intoxicated patient management.

Psychomotor performances relevant for driving under the combined effect of ethanol and synthetic cannabinoids: A systematic review

OBJECTIVE

To determine whether the acute co-consumption of ethanol and synthetic cannabinoids (SCs) increases the risk of a motor vehicle collision and affects the psychomotor performances relevant for driving.

DESIGN

Systematic review of the literature.

DATA SOURCES

Electronic searches were performed in two databases, unrestricted by year, with previously set method and criteria. Search, inclusion and data extraction were performed by two blind authors.

RESULTS

Twenty articles were included, amounting to 31 cases of SCs-ethanol co-consumption. The impairment of psychomotor functions varied widely between studies, ranging from no reported disabilities to severe unconsciousness. Overall, a dose-effect relationship could not be observed.

CONCLUSION

Despite the biases and limitations of the literature studies, it seems likely that the co-consumption poses an increased risk for driving. The drugs might exert a synergistic effect on the central nervous system depression, as well as on aggressiveness and mood alterations. However, more research is needed on the topic.

Characterisation of AMB-FUBINACA metabolism and CB1-mediated activity of its acid metabolite

PURPOSE

AMB-FUBINACA is a synthetic cannabinoid receptor agonist (SCRA) which is primarily metabolised by hepatic enzymes producing AMB-FUBINACA carboxylic acid. The metabolising enzymes associated with this biotransformation remain unknown. This study aimed to determine if AMB-FUBINACA metabolism could be reduced in the presence of carboxylesterase (CES) inhibitors and recreational drugs commonly consumed with it. The affinity and activity of the AMB-FUBINACA acid metabolite at the cannabinoid type-1 receptor (CB₁) was investigated to determine the activity of the metabolite.

METHODS

The effect of CES1 and CES2 inhibitors, and delta-9-tetrahydrocannabinol (Δ⁹-THC) on AMB-FUBINACA metabolism were determined using both human liver microsomes (HLM) and recombinant carboxylesterases. Radioligand binding and cAMP assays comparing AMB-FUBINACA and AMB-FUBINACA acid were carried out in HEK293 cells expressing human CB₁.

RESULTS

AMB-FUBINACA was rapidly metabolised by HLM in the presence and absence of NADPH. Additionally, CES1 and CES2 inhibitors both significantly reduced AMB-FUBINACA metabolism. Furthermore, digitonin (100 µM) significantly inhibited CES1-mediated metabolism of AMB-FUBINACA by ~ 56%, while the effects elicited by Δ⁹-THC were not statistically significant. AMB-FUBINACA acid produced only 26% radioligand displacement consistent with low affinity binding. In cAMP assays, the potency of AMB-FUBINACA was ~ 3000-fold greater at CB₁ as compared to the acid metabolite.

CONCLUSIONS

CES1A1 was identified as the main hepatic enzyme responsible for the metabolism of AMB-FUBINACA to its less potent carboxylic acid metabolite. This biotransformation was significantly inhibited by digitonin. Since other xenobiotics may also inhibit similar SCRA metabolic pathways, understanding these interactions may elucidate why some users experience high levels of harm following SCRA use.

Assessment of dependence potential and abuse liability of Δ8-tetrahydrocannabinol in mice

Delta-8-tetrahydrocannabinol (Δ8-THC) is a psychotropic cannabinoid produced in low quantities in the cannabis plant. Refinements in production techniques, paired with the availability of inexpensive cannabidiol substrate, have resulted in Δ8-THC being widely marketed as a quasi-legal, purportedly milder alternative to Δ9-THC. Yet, little research has probed the behavioral and physiological effects of repeated Δ8-THC use. The present study aimed to evaluate the effects of acute and repeated exposure to Δ8-THC. We hypothesized that Δ8-THC produces effects similar to Δ9-THC, including signs of drug tolerance and dependence. Adult male and female C57BL/6J mice were treated acutely with Δ8-THC (6.25-100 mg/kg, i.p.) or vehicle and tested in the tetrad battery to quantify cannabimimetic effects (i.e., catalepsy, antinociception, hypothermia, immobility) as compared with a non-selective synthetic cannabinoid (WIN 55,212-2) and Δ9-THC. As previously reported, Δ8-THC (≥12.5 mg/kg) induced cannabimimetic effects. Pretreatment with the CB1 receptor-selective antagonist rimonabant (3 mg/kg, i.p.) blocked each of these effects. In addition, repeated administration of Δ8-THC (50 mg/kg, s.c.) produced tolerance, as well as cross-tolerance to WIN 55,212-2 (10 mg/kg, s.c.) in tetrad, consistent with downregulated CB1 receptor function. Behavioral signs of physical dependence in the somatic signs, tail suspension, and marble burying assays were also observed following rimonabant-precipitated withdrawal from Δ8-THC (≥10 mg/kg BID for 6 days). Lastly, Δ8-THC produced Δ9-THC-like discriminative stimulus effects in both male and female mice. Together, these findings demonstrate that Δ8-THC produces qualitatively similar effects to Δ9-THC, including risk of drug dependence and abuse liability.

Substance use and substance use disorders in Africa: An epidemiological approach to the review of existing literature

The relationship between man and substances that have abuse potentials, and whose use has been associated with the development or progression of substance use disorders has continued to evolve in terms of geography, economic implications, and time. History shows that local plants with psychoactive constituents can get exported worldwide through global travel, commerce, or even conquest. Time and globalization also change people’s relationship with substances of abuse; hence, an area that was initially alien to certain substances might evolve to becoming a trafficking hub, and then a destination. A case in point is Africa where a rapidly increasing prevalence of substance use/abuse and substance use disorder among adolescents and young adults is putting enormous strain on the economy, healthcare system, and society at large. However, there appears to be a paucity of scientific literature and data on the epidemiology, risk assessment, and contributing factors to substance use and the development of substance use disorders across Africa. In this narrative review, we examine extant literature (PubMed, Google scholar, Medline) for information on the prevalence, trends, and influencers of substance use and the development of substance use disorders. This is with a view of understanding the determinants of substance use and factors that influence the development of substance use disorders in the region, and how this information can be channeled towards developing a comprehensive intervention and treatment program.

In vitro and in vivo pharmacology of nine novel synthetic cannabinoid receptor agonists

Synthetic cannabinoid receptor agonists (SCRAs) are novel psychoactive substances that bind to and activate CB1 receptors in the brain. The structural manipulations observed in newer SCRAs suggest that manufacturers have incorporated modern drug development techniques into their repertoire, often producing higher CB1 receptor affinity than Δ9-tetrahydrocannabinol (Δ9-THC). This study examined nine SCRAs recently detected by forensic surveillance, some of which caused fatalities: 5F-MDMB-PICA, FUB-144, 5F-MMB-PICA, MMB-4en-PICA, MMB-FUBICA, 5F-EDMB-PINACA, APP-BINACA, MDMB-4en-PINACA, and FUB-AKB48. Compounds were evaluated for CB1 and CB2 receptor binding affinity and functional activation and for their effects on body temperature, time course, and pharmacological equivalence with Δ9-THC in Δ9-THC drug discrimination in mice. All SCRAs bound to and activated CB1 and CB2 receptors with high affinity, with similar or greater affinity for CB2 than CB1 receptors and stimulated [35S]GTPγS binding in CB1 and CB2 expressing cell membranes. All compounds produced hypothermia, with shorter latency to peak effects for SCRAs than Δ9-THC. All SCRAs fully substituted for Δ9-THC in drug discrimination at one or more doses. Rank order potency in producing in vivo effects mostly aligned with rank order CB1 receptor affinities. Potencies for Δ9-THC-like discriminative stimulus effects were similar across sex except Δ9-THC was more potent in females and 5F-MMB-PICA was more potent in males. In summary, 5F-EMDB-PINACA, 5F-MDMB-PICA, MDMB-4en-PINACA, FUB-144, FUB-AKB48, 5F-MMB-PICA, MMB-4en-PICA, and MMB-FUBICA are potent and efficacious SCRAs with pharmacology like that of past SCRAs that have been abused in humans. In contrast, APP-BINACA was efficacious, but had lower potency than most past SCRAs.

Cannabimimetic effects of abused indazole-carboxamide synthetic cannabinoid receptor agonists AB-PINACA, 5F-AB-PINACA and 5F-ADB-PINACA in mice: Tolerance, dependence and withdrawal

BACKGROUND

Chronic abuse of synthetic cannabinoid receptor agonists (SCRAs), known as "K2″ or "Spice", threatens public health and safety. Recently, SCRAs of the indazole-carboxamide structural class have become more prevalent. Preclinical studies investigating the tolerance and dependence potentially involved in chronic SCRA abuse is limited. The present study determined the in vivo effects of chronic exposure to indazole-carboxamide SCRAs, AB-PINACA, 5F-AB-PINACA and 5F-ADB-PINACA compared to the first-generation SCRA, JWH-018.

METHODS

Adult male C57Bl/6 mice were used for dose-effect determinations of hypothermic effects. Adult male NIH Swiss mice were used in biotelemetry studies to assess tolerance to hypothermic effects following repeated SCRA administration over 5 consecutive days, and to determine the role of Phase I drug metabolism via acute CYP450 inhibition in the presence of 1-ABT, a nonspecific CYP450 inhibitor. SCRA dependence was determined in adult male NIH Swiss mice via assessment of rimonabant-precipitated observable sign of withdrawal (i.e., front paw tremors).

RESULTS

All SCRAs elicited dose-dependent hypothermia mediated through cannabinoid CB1 receptors (CB1Rs). 1-ABT increased duration of hypothermia for all SCRAs tested, and increased the magnitude of hypothermia for all SCRAs except 5F-ADB-PINACA. Upon repeated administration, tolerance to hypothermic effects of AB-PINACA, 5F-AB-PINACA and 5F-ADB-PINACA was much less than that of JWH-018. Similarly, rimonabant-precipitated front paw tremors were much less frequent in mice treated with 5F-AB-PINACA and 5F-ADB-PINACA than in mice treated with JWH-018.

CONCLUSIONS

These findings suggest a decreased potential for tolerance and withdrawal among indazole-carboxamide SCRAs, and may imply structural class-dependent profiles of in vivo effects among SCRAs.

Detection of the Synthetic Cannabinoids AB-CHMINACA, ADB-CHMINACA, MDMB-CHMICA, and 5F-MDMB-PINACA in Biological Matrices: A Systematic Review

Simple Summary

Synthetic cannabinoids were originally developed for scientific research and potential therapeutic agents. However, clandestine laboratories synthesize them and circumvent legal barriers by falsely marketing them as incense or herbal products. They have serious adverse effects, and new derivatives are continuously found in the market, making their detection difficult due to the lack of comparative standards. Human matrices are used to identify the type of synthetic cannabinoid and the time of its consumption. This review discusses the use of hair, oral fluid, blood, and urine in the detection and quantification of some of the major synthetic cannabinoids. Based on the results, some recommendations can be followed, for example, the use of hair to detect chronic and retrospective consumption (although sensitive to external contamination) and oral fluid or blood for the simultaneous detection of the parent compounds and their metabolites. If longer detection times than blood or oral fluid are needed, urine is the matrix of choice, although its pH may intervene in the analysis. This work highlights the use of new techniques, such as high-resolution mass spectrometry, to avoid the use of previous standards and to monitor new trends in the drug market.

Abstract

New synthetic cannabinoids (SCs) are emerging rapidly and continuously. Biological matrices are key for their precise detection to link toxicity and symptoms to each compound and concentration and ascertain consumption trends. The objective of this study was to determine the best human biological matrices to detect the risk-assessed compounds provided by The European Monitoring Centre for Drugs and Drug Addiction: AB-CHMINACA, ADB-CHMNACA, MDMB-CHMICA, and 5F-MDMB-PINACA. We carried out a systematic review covering 2015 up to the present date, including original articles assessing detection in antemortem human biological matrices with detailed validation information of the technique. In oral fluid and blood, SC parent compounds were found in oral fluid and blood at low concentrations and usually with other substances; thus, the correlation between SCs concentrations and severity of symptoms could rarely be established. When hair is used as the biological matrix, there are difficulties in excluding passive contamination when evaluating chronic consumption. Detection of metabolites in urine is complex because it requires prior identification studies. LC-MS/MS assays were the most widely used approaches for the selective identification of SCs, although the lack of standard references and the need for revalidation with the continuous emergence of new SCs are limiting factors of this technique. A potential solution is high-resolution mass spectrometry screening, which allows for non-targeted detection and retrospective data interrogation.

Metabolites of Synthetic Cannabinoid 5F-MDMB-PINACA Retain Affinity, Act as High Efficacy Agonists and Exhibit Atypical Pharmacodynamic Properties at CB1 Receptors

Synthetic cannabinoid receptor agonists (SCRAs) are a large group of abused psychoactive compounds that elicit numerous toxic effects not observed with cannabis, including death. Abuse of third-generation SCRA 5F-MDMB-PINACA (also known as 5F-ADB) has been associated with over 40 fatalities. This SCRA is metabolized to several active phase I metabolites, including excessively high post-mortem serum concentrations of an ester hydrolysis metabolite, 5F-MDMB-PINACA-M7 (M7). Although high serum concentrations of M7 (and other active metabolites) have been suggested to contribute to 5F-MDMB-PINACA toxicity, the affinity of M7 for CB1 receptors is unknown and more complete pharmacodynamic characterization of 5F-MDMB-PINACA and its active metabolites is needed. Competition binding and G-protein modulation studies presented here confirm reports that 5F-MDMB-PINACA and a second N-5-hydroxypentyl metabolite (M2) exhibit nM affinity and act as high efficacy agonists at CB1 receptors. Also as previously published, M7 exhibits high efficacy at CB1 receptors; however, demonstrated here for the first time, M7 retains only low μΜ affinity. Empirically derived Kb values indicate rimonabant differentially antagonizes G-protein activation produced by 5F-MDMB-PINACA, relative to Δ9-THC (THC) or its metabolites. Chronic administration of 5F-MDMB-PINACA and metabolites results in CB1 down-regulation, but only 5F-MDMB-PINACA produces desensitization. Although low CB1 affinity/potency of M7 precluded in vivo studies, both M2 and THC produce locomotor suppression and CB1-mediated dose-dependent hypothermia and analgesia in mice. Collectively, these data confirm and extend previous studies suggesting that 5F-MDMB-PINACA is metabolized to active compounds exhibiting atypical pharmacodynamic properties at CB1 receptors, that may accumulate with parent drug to produce severe toxicity.

Electrochemiluminescence sensors and forensic investigations: a viable technique for drug detection?

Novel psychoactive substances (NPS) are today considered one of the major ticking public health time bombs in regard to drug abuse. The inability to identify these substances with current screening methods, sees their distribution remain uninterrupted and contributes to the high death rates amongst users. To tackle this problem, it is vital that new robust screening methods are developed, addressing the limitation of those currently in place, namely colour subjectivity and lack of compatibility with the complex matrices these substances may be found within. To this avail, electrochemical methods have been assessed. These low cost and extremely portable sensors have been successfully applied for the direct detection of a broad range of compounds of interest in a range of matrices including, herbal material, commercial drinks and biological fluids (serum, saliva, sweat and urine). With their high versatility, gifted through a significant degree of flexibility in regard to electrode material a range of sensors have to date been reported. In this review the various electrochemical sensors developed to date for NPS detection will be compared and contrasted, with a special focus upon those utilising electrochemiluminescence (ECL) technology.

Clinical withdrawal symptom profile of synthetic cannabinoid receptor agonists and comparison of effects with high potency cannabis

Synthetic cannabinoid receptor agonists (SCRAs) may be used as an alternative to natural cannabis; however, they may carry a greater risk of problematic use and withdrawal. This study aimed to characterise the withdrawal symptom profile of SCRAs and compare their profile of effect with high-potency herbal cannabis. Global Drug Survey data (2015 and 2016) were used to access a clinically relevant sample of people reporting use of SCRAs >10 times in the past 12-months, a previous SCRA quit attempt, and lifetime use of high-potency herbal cannabis. Participants completed an 11-item SCRA withdrawal symptom checklist and compared SCRAs and high-potency herbal cannabis on their onset and duration of effects, speed of the development of tolerance, severity of withdrawal, and difficulty with dose titration. Participants (n = 284) reported experiencing a mean of 4.4 (95% CI: 4.1, 4.8) withdrawal symptoms after not using SCRAs for >1 day; most frequently reported were sleep issues (59.2%), irritability (55.6%), and low mood (54.2%). Withdrawal symptoms were significantly associated with frequency (>51 vs. 11-50 times per year: IRR = 1.43, 95% CI: 1.16, 1.77, p = 0.005) and quantity (grams per session: IRR = 1.13, 95% CI: 1.05, 1.22, p = 0.001) of SCRA use. Compared to high-potency herbal cannabis, SCRAs were rated as having a faster onset and shorter duration of effects, faster development of tolerance, and more severe withdrawal (p's < 0.001). In conclusion, SCRA withdrawal symptoms are more likely to occur after greater SCRA exposure. The effects of SCRA indicate a more severe withdrawal syndrome and a greater risk of problematic use than natural cannabis.

Synthesis and pharmacological evaluation of newly detected synthetic cannabinoid receptor agonists AB-4CN-BUTICA, MMB-4CN-BUTINACA, MDMB-4F-BUTICA, MDMB-4F-BUTINACA and their analogs

Synthetic cannabinoid receptor agonists (SCRAs) continue to make up a significant portion new psychoactive substances (NPS) detected and seized worldwide. Due to their often potent activation of central cannabinoid receptors in vivo, use of SCRAs can result in severe intoxication, in addition to other adverse health effects. Recent detections of AB-4CN-BUTICA, MMB-4CN-BUTINACA, MDMB-4F-BUTICA and MDMB-4F-BUTINACA mark a continuation in the appearance of SCRAs bearing novel tail substituents. The proactive characterization campaign described here has facilitated the detection of several new SCRAs in toxicological case work. Here we detail the synthesis, characterization, and pharmacological evaluation of recently detected SCRAs, as well as a systematic library of 32 compounds bearing head, tail, and core group combinations likely to appear in future. In vitro radioligand binding assays revealed most compounds showed moderate to high affinity at both CB₁ (pK _i = < 5 to 8.89 ± 0.09 M) and CB₂ (pK _i = 5.49 ± 0.03 to 9.92 ± 0.09 M) receptors. In vitro functional evaluation using a fluorescence-based membrane potential assay showed that most compounds were sub-micromolar to sub-nanomolar agonists at CB₁ (pEC₅₀ = < 5 to 9.48 ± 0.14 M) and CB₂ (pEC₅₀ = 5.92 ± 0.16 to 8.64 ± 0.15 M) receptors. An in silico receptor-ligand docking approach was utilized to rationalize binding trends for CB₂ with respect to the tail substituent, and indicated that rigidity in this region (i.e., 4-cyanobutyl) was detrimental to affinity.

Trends in MDMA-related mortality across four countries

AIMS

To determine trends in 3,4 methylenedioxymethamphetamine (MDMA)-related death rates across Australia, Finland, Portugal and Turkey and to analyse the toxicology and causes of death across countries.

DESIGN

Analysis of MDMA-related deaths extracted from a national coronial database in Australia (2001-19) and national forensic toxicology databases in Finland (2001-17), Portugal (2008-19) and Turkey (2007-17). Presentation of MDMA use and seizure data (market indicators).

SETTING

Australia, Finland, Portugal and Turkey.

CASES

All deaths in which MDMA was considered by the forensic pathologist to be contributory to death.

MEASUREMENTS

Information collected on cause and circumstances of death, demographics and toxicology.

FINDINGS

A total of 1400 MDMA-related deaths were identified in Turkey, 507 in Australia, 100 in Finland and 45 in Portugal. The median age ranged from 24 to 27.5 years, and males represented between 81 and 94% of the deaths across countries. Standardized mortality rates significantly increased across all four countries from 2011 to 2017 during a period of increased purity and availability of MDMA. The underlying cause of death was predominantly due to drug toxicity in Australia (n = 309, 61%), Finland (n = 70, 70%) and Turkey (n = 840, 60%) and other causes in Portugal (n = 25, 56%). Minorities of all deaths across the countries were due to MDMA toxicity alone (13-25%). These deaths had a significantly higher blood MDMA concentration than multiple drug toxicity deaths in Australia, Finland and Turkey. Drugs other than MDMA commonly detected were stimulants (including cocaine, amphetamine and methamphetamine) (Australia 52% and Finland 61%) and alcohol (Australia 46% and Portugal 49%). In addition to MDMA toxicity, benzodiazepines (81%) and opioids (64%) were commonly identified in these deaths in Finland. In comparison, synthetic cannabinoids (15%) and cannabis (33%) were present in a minority of deaths in Turkey.

CONCLUSIONS

Deaths related to 3,4 methylenedioxymethamphetamine (MDMA) increased in Australia, Finland, Portugal and Turkey between 2011 and 2017. Findings show MDMA toxicity alone can be fatal, but multiple drug toxicity remains more prevalent.

The Spicy Story of Cannabimimetic Indoles

The Sterling Research Group identified pravadoline as an aminoalkylindole (AAI) non-steroidal anti-inflammatory pain reliever. As drug design progressed, the ability of AAI analogs to block prostaglandin synthesis diminished, and antinociceptive activity was found to result from action at the CB1 cannabinoid receptor, a G-protein-coupled receptor (GPCR) abundant in the brain. Several laboratories applied computational chemistry methods to ultimately conclude that AAI and cannabinoid ligands could overlap within a common binding pocket but that WIN55212-2 primarily utilized steric interactions via aromatic stacking, whereas cannabinoid ligands required some electrostatic interactions, particularly involving the CB1 helix-3 lysine. The Huffman laboratory identified strategies to establish CB2 receptor selectivity among cannabimimetic indoles to avoid their CB1-related adverse effects, thereby stimulating preclinical studies to explore their use as anti-hyperalgesic and anti-allodynic pharmacotherapies. Some AAI analogs activate novel GPCRs referred to as "Alkyl Indole" receptors, and some AAI analogs act at the colchicine-binding site on microtubules. The AAI compounds having the greatest potency to interact with the CB1 receptor have found their way into the market as "Spice" or "K2". The sale of these alleged "herbal products" evades FDA consumer protections for proper labeling and safety as a medicine, as well as DEA scheduling as compounds having no currently accepted medical use and a high potential for abuse. The distribution to the public of potent alkyl indole synthetic cannabimimetic chemicals without regard for consumer safety contrasts with the adherence to regulatory requirements for demonstration of safety that are routinely observed by ethical pharmaceutical companies that market medicines.

Acute Pharmacological Effects and Oral Fluid Concentrations of the Synthetic Cannabinoids JWH-122 and JWH-210 in Humans After Self-Administration: An Observational Study

Synthetic cannabinoids (SCs) are a group of new psychoactive drugs used recreationally with potential health risks. They are monitored by the EU Early Warning System since 2010 due to severe adverse effects on consumers. JWH-122 and JWH-210 are naphthoylindole SCs and potent cannabinoid receptor CB1 and CB2 agonists. Information about the effects of SCs usually is available from intoxication cases and surveys, and few studies on humans after controlled administration or observational/naturalistic studies using standardized measures of cardiovascular and subjective effects are available. The aim of this study was to evaluate the acute pharmacological effects of JWH-122 and JWH-210 recreational consumption in a 4 h observational study and assess their disposition in oral fluid (OF). Sixteen volunteers self-administered 1 mg dose of JWH-122 (n = 8) or 2.25 mg mean dose of JWH-210 (range 2–3 mg, n = 8) by inhalation (smoking). Physiological parameters including blood pressure (systolic and diastolic), heart rate (HR), and cutaneous temperature were measured. A set of visual analog scales, the 49-item short-form version of the Addiction Research Center Inventory (ARCI), and the Evaluation of the Subjective Effects of Substances with Abuse Potential (VESSPA-SSE) were used for the evaluation of subjective effects. OF was collected at baseline and at 10, 20, and 40 min and 1, 2, 3, and 4 h after self-administration. Statistically significant increases in systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR were observed after JWH-122 self-administration but not after JWH-210 self-administration. JWH-210 self-administration produced significant changes in subjective drug effects, similar to those induced by THC (intensity, high, good effects, and hunger). The subjective effects following JWH-122 consumption were minimal. The maximal effects were mostly observed 20 min after intake. JWH-122 and JWH 210 OF concentration reached a peak 20 min after administration and could not be detected after 3 h. The results demonstrated a different pattern of effects of these two SCs. Due to the limitations of our observational study, further research with a larger sample and controlled studies are needed to better define the acute pharmacological effect and health risk profile of JWH-122 and JWH-210.

Molecular basis for ligand modulation of the cannabinoid CB1 receptor

The cannabinoid CB₁ receptor is the most abundant G protein coupled receptor (GPCR) in the central nervous system, which mediates the functional response to endocannabinoids and Cannabis compounds. A variety of ligands for CB₁ receptors have been developed as promising drug candidates for the treatment of neurological disorders. New high-resolution structures of CB₁ receptor in different functional states have significantly improved our molecular understanding of CB₁ ligand interactions, selectivity, receptor activation and allosteric modulation. These advances have paved the way for development of novel ligands for different therapeutic applications. In this review, we describe the structural determinants for modulation of CB₁ receptors by different types of ligands, as well as the differences between CB₁ and its homologous, the CB₂ receptor.

Cannabis use, abuse, and withdrawal: Cannabinergic mechanisms, clinical, and preclinical findings

Cannabis sativa is the most widely used illicit drug in the world. Its main psychoactive component is delta‐9‐tetrahydrocannabinol (THC), one of over 100 phytocannabinoid compounds produced by the cannabis plant. THC is the primary compound that drives cannabis abuse potential and is also used and prescribed medically for therapeutic qualities. Despite its therapeutic potential, a significant subpopulation of frequent cannabis or THC users will develop a drug use syndrome termed cannabis use disorder. Individuals suffering from cannabis use disorder exhibit many of the hallmarks of classical addictions including cravings, tolerance, and withdrawal symptoms. Currently, there are no efficacious treatments for cannabis use disorder or withdrawal symptoms. This makes both clinical and preclinical research on the neurobiological mechanisms of these syndromes ever more pertinent. Indeed, basic research using animal models has provided valuable evidence of the neural molecular and cellular actions of cannabis that mediate its behavioral effects. One of the main components being central action on the cannabinoid type‐one receptor and downstream intracellular signaling related to the endogenous cannabinoid system. Back‐translational studies have provided insight linking preclinical basic and behavioral biology research to better understand symptoms observed at the clinical level. This narrative review aims to summarize major research elucidating the molecular, cellular, and behavioral manifestations of cannabis/THC use that play a role in cannabis use disorder and withdrawal.

Pharmacology and adverse effects of new psychoactive substances: synthetic cannabinoid receptor agonists

Over the last decade, new psychoactive substances (NPS) have continuously been the focus of the international society since their emergence on the illicit drug market. NPS can be classified into six groups including; synthetic cannabinoid receptor agonists (SCRAs), stimulants, opioids, dissociatives, sedatives/hypnotics, and classic hallucinogens with psychoactive effects. These are sold as "herbal incense," "bath salts," "legal highs," and "research chemicals". They can be synthesized easily with slight changes in the chemical moieties of known psychoactive substances. NPS are sold worldwide via on- and off-line markets without proper scientific evaluation regarding their safety or harmfulness. Abuse of NPS poses a serious public health issue, and systematic studies on their adverse effects are lacking. Therefore, it would be meaningful to collect currently available data in order to understand NPS and to establish viable solutions to cope with the various health issues related to them. In this article, we reviewed the general pharmacological characteristics, recent findings, and adverse effects of representative NPS; SCRAs. SCRAs are known as the most commonly abused NPS. Most SCRAs, cannabinoid receptor 1 and cannabinoid receptor 2 agonists, are often associated with severe toxicities, including cardiotoxicity, immunotoxicity, and even death, unlike natural cannabinoid Δ⁹-Tetrahydrocannabinol.

Self-administration of inhaled delta-9-tetrahydrocannabinol and synthetic cannabinoids in non-human primates

Cannabis and synthetic cannabinoids are abused in spite of possible adverse health consequences. The current study investigated the reinforcing effects of an ecologically relevant mode of administration (inhalation) of delta-9-tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, and three synthetic cannabinoids detected in synthetic cannabinoid products (JWH-018, JWH-073, and HU-210) in non-human primates (NHPs). Male and female (N = 4 each) rhesus macaques were trained to inhale warm air via a metal stem to receive a candy reinforcer, an alcohol aerosol vehicle was then paired with the candy. Dose-dependent responding for inhaled aerosols of THC (2.0-16.0 μg/kg/inhalation), JWH-018 (0.2-1.6 μg/kg/inhalation), JWH-073 (2.0-8.0 μg/kg/inhalation), and HU-210 (1.0-8.0 μg/kg/inhalation) was established using a fixed-ratio five schedule of reinforcement and compared to vehicle (alcohol) self-administration. Dose-dependent responding for inhaled heroin (25.0-100.0 μg/kg/inhalation), a known reinforcer in NHPs, was also established. Responding approximated vehicle levels for many drug doses tested, but at least half of the monkeys responded for ≥ one dose of each cannabinoid and heroin above vehicle, with the exception of THC. Drug deliveries calculated as percent vehicle followed a prototypical inverted-U shaped dose-response curve for cannabinoids and heroin except for THC and JWH-018 (in males). Grouped data according to sex demonstrated that peak percent of vehicle reinforcers earned for THC was greater in males than females, whereas peak percent of vehicle reinforcers earned for JWH-018, HU-210, and heroin were greater in females than males. These findings indicate minimal reinforcing effects of CB1 receptor agonists when self-administered by NHPs via aerosol inhalation. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Historical and Current Perspectives of Synthetic Marijuana: Critical Review

Synthetic marijuana use has increased significantly since 2008 among young adults in the United States, as have adverse reactions to it, leading to a dramatic increase in emergency department visits. However, much of the research conducted on it has been case studies, which report detrimental symptoms on an individual basis. Only a limited number of studies aim to better understand the larger parameters of this epidemic to assist health care providers and policy makers, including early detection, intervention, and adequate treatment. In addition, there has been limited critical review of this substance to help health care professionals educate the public about the negative health effects of using this drug. This article explores the critical reviews of synthetic marijuana, also commonly known as "K2" and "Spice," synthesizing information from literature reviews, case studies, media information, and government websites. Findings were organized by synthetic marijuana's history, description, adverse reactions including withdrawal symptoms and death incidents, detection screening, treatment, and legislative issues. Health care providers need to understand the detrimental effects of this illicit and harmful substance to both the body and mind and sometimes irreversible damage caused to individuals who consume it. Policy makers, the public, and affected individuals and their family members need to be educated as well.

Metabolism of 4F-MDMB-BICA in zebrafish by liquid chromatography-high resolution mass spectrometry

In this study, in vivo metabolic studies of the synthetic cannabinoid 4F-MDMB-BICA were investigated using zebrafish models. The metabolites were identified and structurally illustrated by liquid chromatography-high resolution mass spectrometry. Fourteen phase-I metabolites and four phase-II metabolites were generated from zebrafish. The main metabolic pathways of the phase-I metabolism included N-dealkylation, N-dealkylation combined with hydroxylation, amide hydrolysis, oxidative defluorination, oxidative defluorination to butyric acid, acetic acid formation at the indole side chain, hydroxylation, ester hydrolysis followed by hydroxylation, dehydrogenation, dehydrogenation, and N-dealkylation, and oxidative defluorination subsequently combined with dehydrogenation. The main biotransformations of the phase-II metabolism were glucuronidation and sulfation. Two phase-I metabolites (A1 and A11) and four phase-II metabolites (A2, A3, A4, and A12) were reported for the first time. A14, which was confirmed in human biological samples, was detected only in zebrafish samples but not found in human liver microsome incubation study. The current study indicates that the zebrafish model is a promising tool for elucidating the metabolism of NPS in the future.

Overview of Synthetic Cannabinoids ADB-FUBINACA and AMB-FUBINACA: Clinical, Analytical, and Forensic Implications

ADB-FUBINACA and AMB-FUBINACA are two synthetic indazole-derived cannabinoid receptor agonists, up to 140- and 85-fold more potent, respectively, than trans-∆⁹-tetrahydrocannabinol (∆⁹-THC), the main psychoactive compound of cannabis. Synthesised in 2009 as a pharmaceutical drug candidate, the recreational use of ADB-FUBINACA was first reported in 2013 in Japan, with fatal cases being described in 2015. ADB-FUBINACA is one of the most apprehended and consumed synthetic cannabinoid (SC), following AMB-FUBINACA, which emerged in 2014 as a drug of abuse and has since been responsible for several intoxication and death outbreaks. Here, we critically review the physicochemical properties, detection methods, prevalence, biological effects, pharmacodynamics and pharmacokinetics of both drugs. When smoked, these SCs produce almost immediate effects (about 10 to 15 s after use) that last up to 60 min. They are rapidly and extensively metabolised, being the O-demethylated metabolite of AMB-FUBINACA, 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamide)-3-methylbutanoic acid, the main excreted in urine, while for ADB-FUBINACA the main biomarkers are the hydroxdimethylpropyl ADB-FUBINACA, hydroxydehydrodimethylpropyl ADB-FUBINACA and hydroxylindazole ADB-FUBINACA. ADB-FUBINACA and AMB-FUBINACA display full agonism of the CB1 receptor, this being responsible for their cardiovascular and neurological effects (e.g., altered perception, agitation, anxiety, paranoia, hallucinations, loss of consciousness and memory, chest pain, hypertension, tachycardia, seizures). This review highlights the urgent requirement for additional studies on the toxicokinetic properties of AMB-FUBINACA and ADB-FUBINACA, as this is imperative to improve the methods for detecting and quantifying these drugs and to determine the best exposure markers in the various biological matrices. Furthermore, it stresses the need for clinicians and pathologists involved in the management of these intoxications to describe their findings in the scientific literature, thus assisting in the risk assessment and treatment of the harmful effects of these drugs in future medical and forensic investigations.

Highly sensitive screening and analytical characterization of synthetic cannabinoids in nine different herbal mixtures

The popularity of new psychoactive substances among drug users has become a public health concern worldwide. Among them, synthetic cannabinoids (SCs) represent the largest, most diversified and fastest growing group. Commonly known as 'synthetic marijuana' as an alternative to cannabis, these synthetic compounds are easily accessible via the internet and are sold as 'herbal incenses' under different brand names with no information about the chemical composition. In the present work, we aim to integrate gas chromatography-tandem mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) data as useful strategy for the identification and confirmation of synthetic cannabinoids present in nine seized herbal incenses. The analysis of all samples allowed the initial identification of 9 SCs, namely 5 napthoylindoles (JWH-018, JWH-073, JWH-122, JWH-210, MAM-2201), APINACA, XLR-11 and CP47,497-C8 and its enantiomer. JWH-018 was the most frequently detected synthetic compound (8 of 9 samples), while APINACA and XLR-11 were only identified in one herbal product. Other non-cannabinoid drugs, including oleamide, vitamin E and vitamin E acetate, have also been detected. Oleamide and vitamin E are two adulterants, frequently added to herbal products to mask the active ingredients or added as preservatives. However, to our knowledge, no analytical data about vitamin E acetate was reported in herbal products, being the first time that this compound is identified on this type of samples. The integration data obtained from the used analytical technologies proved to be useful, allowing the preliminary identification of the different SCs in the mixture. Furthermore, the examination of mass spectral fragment ions, as well as the results of both 1D and 2D NMR experiments, enabled the identification and confirmation of the molecular structure of SCs.

Cannabinoids and the Adolescent Patient: A Pragmatic Guide for Pediatric Practitioners

Primary care and emergency medicine practitioners frequently care for adolescents with acute or chronic effects of cannabinoids. Cannabinoid epidemiology and pharmacology are changing as new laws and regulations, new products, and new means of delivery are rapidly developed. A grasp of basic cannabinoid terminology, which is also constantly shifting, helps clinicians obtain histories and discuss diagnoses, treatments, and outcomes with their patients. The ability to identify and treat cannabinoid-associated illnesses such as cannabinoid hyperemesis syndrome, withdrawal syndrome, and acute intoxication with synthetic cannabinoids can reduce morbidity. Research on neurodevelopmental, cognitive, and psychological effects of adolescent cannabinoid use helps clinicians to have informed conversations with their patients, while providing anticipatory guidance. This article is designed with busy clinicians in mind and highlights the practical information necessary to provide care to their adolescent patients. [Pediatr Ann. 2021;50(2):e57-e64.

Modern approaches to the development of synthetic cannabinoid receptor probes

The endocannabinoid system, which spans the central and peripheral nervous systems and regulates many biologic processes, is an important target for probe discovery and medications development. Whereas the earliest endocannabinoid receptor probes were derivatives of the non-selective phytocannabinoids isolated from Cannabis species, modern drug discovery techniques have expanded the definitions of what constitutes a CB1R or CB2R cannabinoid receptor ligand. This review highlights recent advances in synthetic cannabinoid receptor chemistry and pharmacology. We provide examples of new CB1R- and CB2R-selective probes, and discuss rational approaches to the design of peripherally-restricted agents. We also describe structural classes of positive- and negative allosteric modulators (PAMs and NAMs) of CB1R and CB2R. Finally, we introduce new opportunities for cannabinoid receptor probe development that have emerged in recent years, including biased agonists that may lead to medications lacking adverse effects.

New psychoactive substances: a review and updates

New psychoactive substances (NPS) are a heterogeneous group of substances. They are associated with a number of health and social harms on an individual and societal level. NPS toxicity and dependence syndromes are recognised in primary care, emergency departments, psychiatric inpatient and community care settings. One pragmatic classification system is to divide NPS into one of four groups: synthetic stimulants, synthetic cannabinoids, synthetic hallucinogens and synthetic depressants (which include synthetic opioids and benzodiazepines). We review these four classes of NPS, including their chemical structures, mechanism of action, modes of use, intended intoxicant effects, and their associated physical and mental health harms. The current challenges faced by laboratory testing for NPS are also explored, in the context of the diverse range of NPS currently available, rate of production and emergence of new substances, the different formulations, and methods of acquisition and distribution.

Synthesis and in Vitro Cannabinoid Receptor 1 Activity of Recently Detected Synthetic Cannabinoids 4F-MDMB-BICA, 5F-MPP-PICA, MMB-4en-PICA, CUMYL-CBMICA, ADB-BINACA, APP-BINACA, 4F-MDMB-BINACA, MDMB-4en-PINACA, A-CHMINACA, 5F-AB-P7AICA, 5F-MDMB-P7AICA, and 5F-AP7AICA

Synthetic cannabinoid receptor agonists (SCRAs) are an evolving class of new psychoactive substances (NPS) with structurally diverse compounds emerging each year. Due to the rapid pace at which these drugs enter the market, there is often little or nil information regarding the pharmacology of these substances despite widespread human use. In this study, 12 recently emerged SCRAs (reported between 2018 and 2020) were synthesized, analytically characterized, and pharmacologically evaluated using a live cell-based nanoluciferase complementation reporter assay that monitors in vitro cannabinoid receptor type 1 (CB1) activation via its interaction with β-arrestin 2 (βarr2). All synthesized SCRAs acted as agonists of CB1, although differences in potency (EC₅₀ = 2.33-5475 nM) and efficacy (E_max = 37-378%) were noted, and several structure-activity relationships were identified. SCRAs featuring indazole cores (EC₅₀ = 2.33-159 nM) were generally of equal or greater potency than indole analogues (EC₅₀ = 32.9-330 nM) or 7-azaindole derivatives (EC₅₀ = 64.0-5475 nM). Interestingly, with the exception of APP-BINACA (E_max = 75.7%) and 5F-A-P7AICA (E_max = 37.4%), all SCRAs showed greater efficacy than the historical SCRA JWH-018 to which responses were normalized (E_max = 142-378%). The most potent CB1 agonists in the study were ADB-BINACA (EC₅₀ = 6.36 nM), 4F-MDMB-BINACA (EC₅₀ = 7.39 nM), and MDMB-4en-PINACA (EC₅₀ = 2.33 nM). Notably, all of these SCRAs featured an indazole core as well as a "bulky" tert-butyl moiety in the pendant amino acid side chain. This study confirms that recently detected SCRAs 4F-MDMB-BICA, 5F-MPP-PICA, MMB-4en-PICA, CUMYL-CBMICA, ADB-BINACA, APP-BINACA, 4F-MDMB-BINACA, MDMB-4en-PINACA, A-CHMINACA, 5F-AB-P7AICA, 5F-MDMB-P7AICA, and 5F-AP7AICA were all able to activate the CB1 receptor in vitro, albeit to different extents, and are potentially psychoactive in vivo. These results indicate that further evaluation of these widely used NPS is warranted to better understand the risks associated with human consumption of these drugs.

Therapeutic potential and safety considerations for the clinical use of synthetic cannabinoids

The phytocannabinoid Δ9-tetrahydrocannabinol (THC) was isolated and synthesized in the 1960s. Since then, two synthetic cannabinoids (SCBs) targeting the cannabinoid 1 (CB1R) and 2 (CB2R) receptors were approved for medical use based on clinical safety and efficacy data: dronabinol (synthetic THC) and nabilone (synthetic THC analog). To probe the function of the endocannabinoid system further, hundreds of investigational compounds were developed; in particular, agonists with (1) greater CB1/2R affinity relative to THC and (2) full CB1/2R agonist activity. This pharmacological profile may pose greater risks for misuse and adverse effects relative to THC, and these SCBs proliferated in retail markets as legal alternatives to cannabis (e.g., novel psychoactive substances [NPS], "Spice," "K2"). These SCBs were largely outlawed in the U.S., but blanket policies that placed all SCB chemicals into restrictive control categories impeded research progress into novel mechanisms for SCB therapeutic development. There is a concerted effort to develop new, therapeutically useful SCBs that target novel pharmacological mechanisms. This review highlights the potential therapeutic efficacy and safety considerations for unique SCBs, including CB1R partial and full agonists, peripherally-restricted CB1R agonists, selective CB2R agonists, selective CB1R antagonists/inverse agonists, CB1R allosteric modulators, endocannabinoid-degrading enzyme inhibitors, and cannabidiol. We propose promising directions for SCB research that may optimize therapeutic efficacy and diminish potential for adverse events, for example, peripherally-restricted CB1R antagonists/inverse agonists and biased CB1/2R agonists. Together, these strategies could lead to the discovery of new, therapeutically useful SCBs with reduced negative public health impact.

Characterizing Trends in Synthetic Cannabinoid Receptor Agonist Use from Patient Clinical Evaluations during Medical Toxicology Consultation

Synthetic cannabinoid receptor agonists (SCRAs) are a new class of compounds with profound psychoactive effects and potential toxicity. This study characterizes patterns in SCRA abuse using qualitative interviews with individuals receiving medical toxicology consultation. Patients with suspected exposure to a new psychoactive substance were interviewed by medical toxicologists upon presentation for acute care. Investigators collected clinical and qualitative data including knowledge, attitudes, beliefs, and practices related to psychoactive substance use. Responses were categorized by identifying themes, and statistics were generated to describe patterns of use. Overall, 69% (86) of the 124 cases of novel psychoactive substance use entered into the registry were associated with exposure to SCRAs. Most patients (68.8%) had used SCRAs at least once before the presenting episode. 47.7% considered SCRAs to be very easy to obtain, and 44.2% reported paying for the substances while 32.6% acquired it for free. Nearly half (48.8%) of patients reported their primary reason for use was to get high; a small proportion used SCRAs to avoid testing positive on drug screening (6.9%) or as an alternative to marijuana (4.6%). Findings suggest an independent and stable culture is developing around the use of SCRAs separate from their appeal as an "undetectable" alternative to marijuana.

Synthetic cannabinoid CP-55,940 induces apoptosis in a human skeletal muscle model via regulation of CB1 receptors and L-type Ca2+ channels

Rhabdomyolysis has been reported in patients who abuse synthetic cannabinoids. However, no studies have yet assessed whether these cases reflect the direct cytotoxicity of synthetic cannabinoids on skeletal muscle, a possibility that the present study sought to address. Specifically, this study investigated the cytotoxicity of the synthetic cannabinoid CP-55,940, a compound that acts equally on both types of cannabinoid receptors (CB₁ and CB₂), in a human embryonic rhabdomyosarcoma (RD) cell line. Exposure of these cells to CP-55,940 resulted in concentration-dependent decreases in cell viability. These effects were attenuated by pre-incubation with AM251 (30 µM), a selective CB₁ receptor antagonist, but not by pre-incubation with AM630 (30 µM), a selective CB₂ receptor antagonist. Following treatment with CP-55,940, RD cells exhibited apoptosis, as indicated by the accumulation of annexin-V, activation of caspase-3, and a loss of the mitochondrial membrane potential. Additionally, CP-55,940 treatment of RD cells led to increases in intracellular Ca²⁺ levels. CP-55,940-induced cell death was significantly attenuated in the absence of extracellular Ca²⁺, and was partially decreased by pre-incubation with verapamil (5 µM) or diltiazem (5 µM), compounds that block the L-type Ca²⁺ channel. Our results indicate that the cytotoxicity of CP-55,940 towards RD cells (skeletal muscle cells) is mediated by the CB₁ receptor, but not by the CB₂ receptor. Our results further suggest that calcium influx through the L-type channel may play an important role in the apoptosis induced by these compounds.