Cannabinoids are involved in physiological and neuromodulatory processes through their interactions with the human cannabinoid receptor-based endocannabinoid system. Their association with neurodegenerative diseases and brain reward pathways underscores the importance of evaluating and modulating cannabinoid activity for both understanding physiological mechanisms and developing therapeutic drugs. The use of agonists and antagonists could be strategic approaches for modulation. In this study, we introduce a bioelectronic sensor designed to monitor cannabinoid binding to receptors and assess their agonistic and antagonistic properties. We produced human cannabinoid receptor 1 (hCB1R) via an Escherichia coli expression system and incorporated it into nanodiscs (NDs). These hCB1R-NDs were then immobilized on a single-walled carbon nanotube field-effect transistor (swCNT-FET) to construct a bioelectronic sensing platform. This novel system can sensitively detect the cannabinoid ligand anandamide (AEA) at concentrations as low as 1 fM, demonstrating high selectivity and real-time response. It also successfully identified the hCB1R agonist Δ9-tetrahydrocannabinol and observed that the hCB1R antagonist rimonabant diminished the sensor signal upon AEA binding, indicating the antagonism-based modulation of ligand interaction. Consequently, our bioelectronic sensing platform holds potential for ligand detection and analysis of agonism and antagonism.

The emergence of inflammatory diseases is a heavy burden on modern societies. Cannabis has been used for several millennia to treat inflammatory disorders such as rheumatism or gout. Since the characterization of cannabinoid receptors, CB1 and CB2, the potential of cannabinoid pharmacotherapy in inflammatory conditions has received great interest. Several studies have identified the importance of these receptors in immune cell migration and in the production of inflammatory mediators. As the presence of the CB2 receptor was documented to be more predominant in immune cells, several pharmacological agonists and antagonists have been designed to treat inflammation. To better define the potential of the CB2 receptor, three online databases, PubMed, Google Scholar and clinicaltrial.gov, were searched without language restriction. The full texts of articles presenting data on the endocannabinoid system, the CB2 receptor and its role in modulating inflammation in vitro, in animal models and in the context of clinical trials were reviewed. Finally, we discuss the clinical potential of the latest cannabinoid-based therapies in inflammatory diseases.

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Growing evidence indicates that activation of cannabinoid type 2 (CB2) receptors protects dopamine neurons in the pathogenesis of Parkinson\'s disease (PD). However, the mechanisms underlying neuroprotection mediated by CB2 receptors are still elusive. In this study, we investigated the effects of CB2 receptor activation on 6-hydroxydopamine (6-OHDA)-induced dopamine neuron degeneration and iron accumulation in the substantia nigra (SN) of rats. We found that treatment with JWH133, a selective CB2 receptor agonist, significantly improved the apomorphine (APO)-induced rotational behavior in 6-OHDA-treated rats. The decreased numbers of tyrosine hydroxylase (TH)-positive neurons and reduced TH protein expression in the lesioned SN of rats were effectively restored by JWH133. Moreover, we found that JWH133 inhibited the increase of iron-staining cells in the lesioned SN of rats. To explore the protective mechanisms of activation of CB2 receptors on dopamine neurons, we further observed the effect of JWH133 on 1-methyl-4-phenylpyridinium (MPP+)-treated primary cultured ventral mesencephalon (VM) neurons from rats. We found that JWH133 significantly inhibited the increase of intracellular reactive oxygen species (ROS), the activation of Caspase-3, the decrease of mitochondrial transmembrane potential (ΔΨm), and the decrease of Bcl-2/Bax protein expression caused by MPP+ treatment. JWH133 also inhibited the MPP+-induced upregulation of divalent metal transporter-1 (DMT1) and downregulation of ferroportin 1 (FPN1). Furthermore, JWH133 also suppressed the MPP+-accelerated iron influx in the VM neurons. These results suggest that activation of CB2 receptor suppresses MPP+-induced cellular iron accumulation and prevents neurodegeneration.NEW & NOTEWORTHY Expression of cannabinoid type 2 receptors (CB2Rs) was discovered on dopamine neurons in recent years. The role of CB2R expressed on dopamine neurons in the pathogenesis of Parkinson\'s disease (PD) has not been fully elucidated. The content of iron accumulation in the brain is closely related to the progress of PD. We verified the inhibitory effect of CB2R on iron deposition in dopamine neurons through experiments, which provided a new idea for the treatment of PD.

A novel synthetic cannabinoid receptor agonist (SCRA), ADMB-FUBIATA, featuring an acetamide-linked structure, has emerged on the illicit drug market. To provide dependable verification of its consumption and identify reliable biomarkers, we investigated an in vitro metabolism study of ADMB-FUBIATA incubated with human primary hepatocytes (HPHs) for the first time and correlated our findings with those from human liver microsomes (HLMs). In this work, ADMB-FUBIATA (10 μM) was incubated with HLM and HPH for 1 and 5 h, respectively, and then subjected to LC-quadrupole-orbitrap MS. A total of 25 metabolites across 8 metabolic pathways were identified after incubation with HLM and HPH, respectively. Monohydroxylation and N-dealkylation were the major metabolic pathways, and formation to ketone was first identified. In addition, the metabolism of ADMB-FUBIATA were found to be mediated by multiple CYP450 enzymes, predominantly CYP2C19, 2D6, and 3A4. This research also initially characterized the fragmentation patterns of the metabolites of ADMB-FUBIATA, elaborating on their structural relationship with ADMB-FUBIATA analogs. To effectively monitor ADMB-FUBIATA abuse, metabolites M4 and M1 were proposed as reliable biomarkers by cross-validating the HLM and HPH incubation results.

The reticular thalamic nucleus (RTN) is a thin shell that covers the dorsal thalamus and controls the overall information flow from the thalamus to the cerebral cortex through GABAergic projections that contact thalamo-cortical neurons (TC). RTN neurons receive glutamatergic afferents fibers from neurons of the sixth layer of the cerebral cortex and from TC collaterals. The firing mode of RTN neurons facilitates the generation of sleep-wake cycles; a tonic mode or desynchronized mode occurs during wake and REM sleep and a burst-firing mode or synchronized mode is associated with deep sleep. Despite the presence of cannabinoid receptors CB1 (CB1Rs) and mRNA that encodes these receptors in RTN neurons, there are few works that have analyzed the participation of endocannabinoid-mediated transmission on the electrical activity of RTN. Here, we locally blocked or activated CB1Rs in ketamine anesthetized rats to analyze the spontaneous extracellular spiking activity of RTN neurons. Our results show the presence of a tonic endocannabinoid input, since local infusion of AM 251, an antagonist/inverse agonist, modifies RTN neurons electrical activity; furthermore, local activation of CB1Rs by anandamide or WIN 55212-2 produces heterogeneous effects in the basal spontaneous spiking activity, where the main effect is an increase in the spiking rate accompanied by a decrease in bursting activity in a dose-dependent manner; this effect is inhibited by AM 251. In addition, previous activation of GABA-A receptors suppresses the effects of CB1Rs on reticular neurons. Our results show that local activation of CB1Rs primarily diminishes the burst firing mode of RTn neurons.

The use of synthetic cannabinoid receptor agonists (SCRAs) represents a public health concern. Besides abuse liability and cognitive impairments, SCRAs consumption is associated with serious medical consequences in humans, including cardiotoxicity. The precise mechanisms underlying cardiac or other toxicities induced by SCRAs are not well understood. Here, we used in silico, in vivo, and ex vivo approaches to investigate the toxicological consequences induced by exposure to the SCRA JWH-018. Along with in silico predictive toxicological screening of 36 SCRAs by MC4PC software, adult male Sprague-Dawley rats were repeatedly exposed to JWH-018 (0.25 mg/kg ip) for 14 consecutive days, with body temperature and cardiovascular parameters measured over the course of treatment. At 1 and 7 days after JWH-018 discontinuation, multiorgan tissue pathologies and heart mitochondria bioenergetics were assessed. The in silico findings predicted risk of cardiac adverse effects specifically for JWH-018 and other aminoalkylindole SCRAs (i.e., electrocardiogram abnormality and QT prolongation). The results from rats revealed that repeated, but not single, JWH-018 exposure induced hypothermia and cardiovascular stimulation (e.g., increased blood pressure and heart rate) which persisted throughout treatment. Post-mortem findings demonstrated cardiac lesions (i.e., vacuolization, waving, edema) 1 day after JWH-018 discontinuation, which may contribute to lung, kidney, and liver tissue degeneration observed 7 days later. Importantly, repeated JWH-018 exposure induced mitochondrial dysfunction in cardiomyocytes, i.e., defective lipid OXPHOS, which may represent one mechanism of JWH-018-induced toxicity. Our results demonstrate that repeated administration of even a relatively low dose of JWH-018 is sufficient to affect cardiovascular function and induce enduring toxicological consequences, pointing to risks associated with SCRA consumption.

Since late 2019, fortification of \'regular\' cannabis plant material with synthetic cannabinoid receptor agonists (SCRAs) has become a notable phenomenon on the drug market. As many SCRAs pose a higher health risk than genuine cannabis, recognizing SCRA-adulterated cannabis is important from a harm reduction perspective. However, this is not always an easy task as adulterated cannabis may only be distinguished from genuine cannabis by dedicated, often expensive and time-consuming analytical techniques. In addition, the dynamic nature of the SCRA market renders identification of fortified samples a challenging task. Therefore, we established and applied an in vitro cannabinoid receptor 1 (CB1) activity-based procedure to screen plant material for the presence of SCRAs.
The assay principle relies on the functional complementation of a split-nanoluciferase following recruitment of β-arrestin 2 to activated CB1. A straightforward sample preparation, encompassing methanolic extraction and dilution, was optimized for plant matrices, including cannabis, spiked with 5 µg/mg of the SCRA CP55,940.
The bioassay successfully detected all samples of a set (n = 24) of analytically confirmed authentic Spice products, additionally providing relevant information on the \'strength\' of a preparation and whether different samples may have originated from separate batches or possibly the same production batch. Finally, the methodology was applied to assess the occurrence of SCRA adulteration in a large set (n = 252) of herbal materials collected at an international dance festival. This did not reveal any positives, i.e. there were no samples that yielded a relevant CB1 activation.
In summary, we established SCRA screening of herbal materials as a new application for the activity-based CB1 bioassay. The simplicity of the sample preparation, the rapid results and the universal character of the bioassay render it an effective and future-proof tool for evaluating herbal materials for the presence of SCRAs, which is relevant in the context of harm reduction.

UNASSIGNED: Cannabis is the most common recreational drug worldwide and synthetic cannabinoid receptor agonists are currently the largest group of new psychoactive substances. The aim of this study was to compare the clinical features and outcomes of lone acute cannabis toxicity with lone acute synthetic cannabinoid receptor agonist toxicity in a large series of presentations to European emergency departments between 2013-2020.
UNASSIGNED: Self-reported drug exposure, clinical, and outcome data were extracted from the European Drug Emergencies Network Plus which is a surveillance network that records data on drug-related emergency department presentations to 36 centres in 24 European countries. Cannabis exposure was considered the control in all analyses. To compare the lone cannabis and lone synthetic cannabinoid receptor agonist groups, univariate analysis using chi squared testing was used for categorical variables and non-parametric Mann-Whitney U- testing for continuous variables. Statistical significance was defined as a P value of <0.05.
UNASSIGNED: Between 2013-2020 there were 54,314 drug related presentations of which 2,657 were lone cannabis exposures and 503 lone synthetic cannabinoid receptor agonist exposures. Synthetic cannabinoid receptor agonist presentations had statistically significantly higher rates of drowsiness, coma, agitation, seizures and bradycardia at the time of presentation. Cannabis presentations were significantly more likely to have palpitations, chest pain, hypertension, tachycardia, anxiety, vomiting and headache.
UNASSIGNED: Emergency department presentations involving lone synthetic cannabinoid receptor agonist exposures were more likely to have neuropsychiatric features and be admitted to a psychiatric ward, and lone cannabis exposures were more likely to have cardiovascular features. Previous studies have shown variability in the acute toxicity of synthetic cannabinoid receptor agonists compared with cannabis but there is little comparative data available on lone exposures. There is limited direct comparison in the current literature between lone synthetic cannabinoid receptor agonist and lone cannabis exposure, with only two previous poison centre series and two clinical series. Whilst this study is limited by self-report being used to identify the drug(s) involved in the presentations, previous studies have demonstrated that self-report is reliable in emergency department presentations with acute drug toxicity.
UNASSIGNED: This study directly compares presentations with acute drug toxicity related to the lone use of cannabis or synthetic cannabinoid receptor agonists. It supports previous findings of increased neuropsychiatric toxicity from synthetic cannabinoid receptor agonists compared to cannabis and provides further data on cardiovascular toxicity in lone cannabis use.

Semi-synthetic cannabinoids (SSCs) including hexahydrocannabinol (HHC) are emerging on the drug market and sold openly as purportedly legal replacements for cannabis and Δ9-THC. By the beginning of 2024, 24 European countries had identified HHC, often sold openly in edibles (foods/candy), vapes and low-THC cannabis flowers and resins. The SSC market is developing rapidly, with HHC acetate (HHC-O), hexahydrocannabiphorol (HHC-P) and others recently identified. These developments may mark the first major change in the market for \'legal\' replacements to cannabis since \'Spice\' containing synthetic cannabinoids, such as JWH-018, emerged in 2008. Currently, there are some data available on the pharmacology of SSCs, which is crucial for understanding their effects, evaluating health risks and informing public health responses. This study focused on characterizing the in vitro activation of the human CB1 receptor by the (R)- and (S)-epimers of HHC, HHC-P and HHC-O. Using recombinant CHO-K1 cells expressing the human CB1 receptor, the potency (EC50) and efficacy were determined. It was established that (9R)-HHC and (9R)-HHC-P activated the CB1 receptor as partial agonists and with five and two times lower potency compared to JWH-018, respectively, while the (S)-epimers exhibited even lower potency. The (R)-epimer of HHC-O activate the CB1 receptor to even lesser extent and the (S)-epimer showed no activation. For HHC and HHC-P, all epimers exhibited similar level of efficacy. This available evidence suggests cannabimimetic effects of the tested SSC with the exception for the acetates that likely function as pro-drugs in vivo.