BACKGROUND: The mental health benefits of cannabidiol (CBD) are promising but can be inconsistent, in part due to challenges in defining an individual\'s effective dosage. In schizophrenia, alterations in anandamide (AEA) concentrations, an endocannabinoid (eCB) agonist of the eCB system, reflect positively on treatment with CBD. Here, we expanded this assessment to include eCBs alongside AEA congeners, comparing phytocannabinoids and dosage in a clinical setting.
METHODS: Liquid chromatography-tandem mass spectrometry quantified changes in serum levels of AEA, 2-arachidonoylglycerol (2-AG), alongside AEA-related compounds oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), which were attained from two independent, parallel-designed, clinical trials investigating single, oral CBD (600 or 800 mg), delta-9-tetrahydrocannabinol (Δ9-THC, 10 or 20 mg) and combination administration (CBD|800 mg+Δ9-THC|20 mg) in healthy volunteers (HVs, n=75). Concentrations were measured at baseline (t=0), 65 and 160 min post administration.
RESULTS: CBD-led increases in AEA (1.6-fold), OEA and PEA (1.4-fold) were observed following a single 800 mg (pcorr<0.05) but not 600 mg dosage. Declining AEA was observed with Δ9-THC at 10 mg (-1.3-fold) and 20 mg (-1.4-fold) but restored to baseline levels by 160 min. CBD+Δ9-THC yielded the highest increases in AEA (2.1-fold), OEA (1.9-fold) and PEA (1.8-fold) without reaching a maximal response.
CONCLUSIONS: CBD-administered effects towards AEA, OEA and PEA are consistent with phase II trials reporting clinical improvement for acute schizophrenia (CBD≥800 mg). Including Δ9-THC appears to enhance the CBD-induced response towards AEA and its congeners. Our results warrant further investigations into the potential of these lipid-derived mediators as metabolic measures for CBD dose prescription and co-cannabinoid administration.

Plasma levels of endocannabinoids (eCBs) are very dynamic and variable in different circumstances and pathologies. The aim of the study was to determine the levels of the main eCBs and N-acylethanolamines (NAEs) in COVID-19 patients during the acute and post-acute phase of SARS-CoV-2 infection. Samples collected before December 31, 2020 were used for the determination of circulating eCB levels by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The association between plasma eCB measurements and biochemical and hematological parameters, as well as serum IL-6 levels, was evaluated. Samples of 64 individuals were analysed, n = 18 healthy donors, n = 30 acute, and n = 16 post-acute patients. Plasma levels of 2-arachidonoylglycerol (2-AG), were significantly elevated in COVID-19 patients when compared to healthy individuals. Plasma N-palmitoylethanolamide (PEA) and N-arachidonoylethanolamide (AEA) levels were found to be decreased in post-acute patient samples. These results suggest that 2-AG plays an important role in the inflammatory cascade in COVID-19 disease; in addition, eCBs might be involved in the post-acute pathogenesis of COVID-19. This study provides evidence of altered levels of circulating eCBs as a consequence of SARS-CoV-2 infection.

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.

BACKGROUND: Schisandra chinensis lignan (SCL), a major active component of the traditional functional Chinese medicine Schisandra chinensis, has been reported to have antidepressant effects. Its mechanisms include alleviating intestinal barrier injury (IBI) by resolving intestinal microflora, anti-inflammation, and neuroprotection. SCL also regulates endogenous cannabinoid system, and it is closely related to the onset and development of depression.
OBJECTIVE: We investigated a new treatment strategy for depression, i.e., alleviating IBI by regulating the endogenous cannabinoid system for antidepressant effects, as well as conducted in-depth research to explore the specific mechanism.
METHODS: Behavioral analysis was conducted to detect the occurrence of depressive-like behavior in C57BL/6 mice. We used hematoxylin-eosin staining, periodic acid-Schiff staining, and immunofluorescence to evaluate IBI. Network pharmacology and Western blotting (WB) were used to predict and confirm that the amelioration effect of SCL was associated with anti-inflammation and anti-apoptosis. Combined with the levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG), we conducted the Pearson analysis between the AEA, 2-AG levels and the major targets identified and validated by network pharmacology and WB. Subsequently, URB-597, a fatty acid amide hydrolase (FAAH) antagonist with an AEA hydrolase-inhibiting effect, was administered to the mice, and behavioral analysis and apoptotic proteins were verified. Plasma endocannabinoid levels after URB-597 supplementation were measured via 6470 Triple Quadrupole LC/MS. Finally, the cannabinoid receptor type 2 (CB2R) antagonist AM630 was administered to mice, and immunofluorescence and WB were performed to assess the proteins of IBI and anti-inflammation.
RESULTS: The study demonstrated that SCL alleviated depressive-like behaviours and ameliorated IBI. Network pharmacology and WB confirmed that the improvement of IBI was related to the anti-inflammatory and anti-apoptotic pathways. Pearson results showed that AEA levels were positively correlated with inflammation and apoptosis, with a greater contribution to apoptosis. In-depth studies validated that the URB-597 administration reversed the positive effects of SCL on depressive-like behavior and anti-apoptosis. Similarly, URB-597 counteracted AEA levels reduced by SCL and decreased 2-AG levels. Furthermore, AM630 supplementation antagonized SCL\'s effect of improving IBI by reactivating the MAPK/NF-κB inflammation pathway.
CONCLUSIONS: Overall, SCL, in collaboration with the endogenous cannabinoid system regulated by SCL, alleviates depression associated IBI. The specific mechanism involes SCL decreasing AEA levels to inhibit colon tissue cell apoptosis by up-regulating FAAH. Simultaneously, it directly triggers CB2R to reduce inflammation responses, further alleviating IBI.

2-arachidonoylglycerol (2-AG) is the most abundant endocannabinoid (EC), acting as a full agonist at both CB1 and CB2 cannabinoid receptors. It is synthesized on demand in postsynaptic membranes through the sequential action of phosphoinositide-specific phospholipase Cβ1 (PLCβ1) and diacylglycerol lipase α (DAGLα), contributing to retrograde signaling upon interaction with presynaptic CB1. However, 2-AG production might also involve various combinations of PLC and DAGL isoforms, as well as additional intracellular pathways implying other enzymes and substrates. Three other alternative pathways of 2-AG synthesis rest on the extracellular cleavage of 2-arachidonoyl-lysophospholipids by three different hydrolases: glycerophosphodiesterase 3 (GDE3), lipid phosphate phosphatases (LPPs), and two members of ecto-nucleotide pyrophosphatase/phosphodiesterases (ENPP6-7). We propose the names of AlterAG-1, -2, and -3 for three pathways sharing an ectocellular localization, allowing them to convert extracellular lysophospholipid mediators into 2-AG, thus inducing typical signaling switches between various G-protein-coupled receptors (GPCRs). This implies the critical importance of the regioisomerism of both lysophospholipid (LPLs) and 2-AG, which is the object of deep analysis within this review. The precise functional roles of AlterAGs are still poorly understood and will require gene invalidation approaches, knowing that both 2-AG and its related lysophospholipids are involved in numerous aspects of physiology and pathology, including cancer, inflammation, immune defenses, obesity, bone development, neurodegeneration, or psychiatric disorders.

BACKGROUND: Major Depressive Disorder (MDD) and Alcohol Use Disorder (AUD) are two high-prevalent conditions where the Endocannabinoid system (ECS) is believed to play an important role. The ECS regulates how different neurotransmitters interact in both disorders, which is crucial for controlling emotions and responses to stress and reward stimuli. Measuring peripheral endocannabinoids (eCBs) in human serum and plasma can help overcome the limitations of detecting endocannabinoid levels in the brain. This systematic review aims to identify levels of peripheral eCBs in patients with MDD and/or AUD and find eCBs to use as diagnostic, prognostic biomarkers, and potential therapeutic targets.
METHODS: We conducted a systematic literature search according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines from the earliest manuscript until October 22, 2023, in three electronic databases. We included studies of human adults who had a current diagnosis of AUD and/or MDD and evaluated plasma or serum endocannabinoids. We carefully considered known variables that may affect endocannabinoid levels.
RESULTS: We included 17 articles in this systematic review, which measured peripheral eCBs in 170 AUD and 359 MDD patients. Stressors increase peripheral 2-arachidonyl-glycerol (2-AG) concentrations, and 2-AG may be a particular feature of depression severity and chronicity. Anxiety symptoms are negatively correlated with anandamide (AEA) concentrations, and AEA significantly increases during early abstinence in AUD. Studies suggest a negative correlation between Oleoylethanolamide (OEA) and length of abstinence in AUD patients. They also show a significant negative correlation between peripheral levels of AEA and OEA and fatty acid amide hydrolase (FAAH) activity. Eicosapentaenoylethanolamide (EPEA) is correlated to clinical remission rates in depression. Included studies show known variables such as gender, chronicity, symptom severity, comorbid psychiatric symptoms, length of abstinence in the case of AUD, and stress-inducibility that can affect peripheral eCBs.
CONCLUSIONS: This systematic review highlights the important role that the ECS plays in MDD and AUD. Peripheral eCBs appear to be useful biomarkers for these disorders, and further research may identify potential therapeutic targets. Using accessible biological samples such as blood in well-designed clinical studies is crucial to develop novel therapies for these disorders.

Cannabinoid and serotonin systems regulate many biological processes. The aim of the present study was to investigate the functional interaction between the cannabinoid and serotonergic systems of the primary somatosensory region (S1) of the brain in epileptiform activity caused by penicillin. The ACEA (an agonist of CB1 receptor), AM‑251 (an antagonist of CB1 receptor), 8‑OH‑DPAT (an agonist of 5‑HT1A receptor) and WAY‑100635 (an antagonist of 5‑HT1A receptor) were administered into the S1 after the same site administration of penicillin in urethane‑anesthetized rats. Electrocorticographic recording was done for a 90‑min period. The spike waves number and amplitude were recorded in 15‑min intervals. Areas under the curve (AUC) of the above‑mentioned spike alterations was calculated in 90 min. Spike waves with frequency of 30/min and amplitude of 1.3 mV were appeared after penicillin microinjection. The ACEA (50 ng), 8‑OH‑DPAT (500 ng) and ACEA (10 ng) plus 8‑OH‑DPAT (100 ng) reduced epileptiform activity. The AM‑251 (50 ng) and WAY‑100365 (500 ng) prevented the reducing effects of ACEA (50 ng) and 8‑OH‑DPAT (500 ng). The AM‑251 alone increased spike waves frequency. The AUC results supported the effects of the above‑mentioned treatments. The results showed that activating CB1 and 5‑HT1A receptors in the S1 may reduce the epileptiform activity caused by penicillin. Therefore, alone and together activation of central CB1 and 5‑HT1A receptors might be considered in the management of epilepsy treatment.

Our laboratory previously developed a method for assessing experimentally induced pain perception through a 2-min constant heat pain stimulation. However, the traditional analysis relying on group means struggles to interpret the considerable inter-individual variability due to the dynamic nature of the response. Recently, trajectory analysis techniques based on extended mixed models have emerged, providing insights into distinct response profiles. Notably, these methods have never been applied to pain paradigms before. Furthermore, various socio-demographic and neurobiological factors, including endocannabinoids, may account for these inter-individual differences. This study aims to apply the novel analysis to dynamic pain responses and investigate variations in response profiles concerning socio-demographic, psychological, and blood endocannabinoid concentrations. 346 pain-free participants were enrolled in a psychophysical test involving a continuous painful heat stimulation lasting for 2 min at a moderate intensity. Pain perception was continuously recorded using a computerized visual scale. Dynamic pain response analyses were conducted using the innovative extended mixed model approach. In contrast to the traditional group-mean analysis, the extended mixed model revealed three pain response trajectories. Trajectory 1 is characterized by a delay peak pain. Trajectory 2 is equivalent to the classic approach (peak pain follow by a constant and moderate increase of pain perception). Trajectory 3 is characterized by extreme responses (steep peak pain, decrease, and increase of pain perception), Furthermore, age and blood anandamide levels exhibited significant variations among these three trajectories. Using an innovative statistical approach, we found that a large proportion of our sample had a response significantly different from the average expected response. Endocannabinoid system seems to play a role in pain response profile.

BACKGROUND: Posttraumatic headache (PTH) is a common and debilitating symptom following repetitive mild traumatic brain injury (rmTBI), and it mainly resembles a migraine-like phenotype. While modulation of the endocannabinoid system (ECS) is effective in treating TBI and various types of pain including migraine, the role of augmentation of endocannabinoids in treating PTH has not been investigated.
METHODS: Repetitive mild TBI was induced in male C57BL/6J mice using the non-invasive close-head impact model of engineered rotational acceleration (CHIMERA). Periorbital allodynia was assessed using von Frey filaments and determined by the \"Up-Down\" method. Immunofluorescence staining was employed to investigate glial cell activation and calcitonin gene-related peptide (CGRP) expression in the trigeminal ganglion (TG) and trigeminal nucleus caudalis (TNC) of the rmTBI mice. Levels of 2-arachidonoyl glycerol (2-AG), anandamide (AEA), and arachidonic acid (AA) in the TG, medulla (including TNC), and periaqueductal gray (PAG) were measured by mass spectrometry. The therapeutic effect of endocannabinoid modulation on PTH was also assessed.
RESULTS: The rmTBI mice exhibited significantly increased cephalic pain hypersensitivity compared to the sham controls. MJN110, a potent and selective inhibitor of the 2-AG hydrolytic enzyme monoacylglycerol lipase (MAGL), dose-dependently attenuated periorbital allodynia in the rmTBI animals. Administration of CGRP at 0.01 mg/kg reinstated periorbital allodynia in the rmTBI animals on days 33 and 45 post-injury but had no effect in the sham and MJN110 treatment groups. Activation of glial cells along with increased production of CGRP in the TG and TNC at 7 and 14 days post-rmTBI were attenuated by MJN110 treatment. The anti-inflammatory and anti-nociceptive effects of MJN110 were partially mediated by cannabinoid receptor activation, and the pain-suppressive effect of MJN110 was completely blocked by co-administration of DO34, an inhibitor of 2-AG synthase. The levels of 2-AG in TG, TNC and PAG were decreased in TBI animals, significantly elevated and further reduced by the selective inhibitors of 2-AG hydrolytic and synthetic enzymes, respectively.
CONCLUSIONS: Enhancing endogenous levels of 2-AG appears to be an effective strategy for the treatment of PTH by attenuating pain initiation and transmission in the trigeminal pathway and facilitating descending pain inhibitory modulation.

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.