The endocannabinoid system and the brain

Advances in targeted liquid chromatography-tandem mass spectrometry methods for endocannabinoid and N-acylethanolamine quantification in biological matrices: A systematic review

Liquid chromatography paired with tandem mass spectrometry (LC-MS/MS) is the gold standard in measurement of endocannabinoid concentrations in biomatrices. We conducted a systematic review of literature to identify advances in targeted LC-MS/MS methods in the period 2017-2024. We found that LC-MS/MS methods for endocannabinoid quantification are relatively consistent both across time and across biomatrices. Recent advances have primarily been in three areas: (1) sample preparation techniques, specific to the chosen biomatrix; (2) the range of biomatrices tested, recently favoring blood matrices; and (3) the breadth of endocannabinoid and endocannabinoid-like analytes incorporated into assays. This review provides a summary of the recent literature and a guide for researchers looking to establish the best methods for quantifying endocannabinoids in a range of biomatrices.

From smooth brains to rocky mountains: Quentin Pittman in a Quintessentially Canadian career

This commentary is to honour Dr Quentin Pittman as he steps back from an active role in academia. Pittman's work leaves a legacy of ground-breaking discoveries, impeccable research, and generous mentorship. His work on thermoregulation, vasopressin, perinatal programming, and hypothalamic function laid a good part of the foundation of the psychoneuroimmunology research we do today. His interest in neuroinflammation led to important findings in animal models of chronic peripheral inflammation including colitis and central inflammatory states observed in epilepsy and multiple sclerosis. His integrative approach, ranging from electrophysiological recordings to whole animal behaviour helped answer physiological questions involving the orchestrated functions and interactions of multiple organs. He is one of a few neuroscientists who raised the question of the contribution of peripheral organs to brain function and plasticity at a time when the field was largely neurocentric. Pittman has enhanced our collective understanding of the effects of neonatal inflammation (and other models of perinatal programming) on the adult brain, and has even revealed key ways in which neurons in the brain communicate with each other, through his work on vasopressin, endocannabinoids, and other transmitters. Altogether, Quentin Pittman's interdisciplinary work has laid a solid foundation for psychoneuroimmunology research and groundbreaking insight into brain-body integration.

A Pilot Randomized Placebo-Controlled Crossover Trial of Medicinal Cannabis in Adolescents with Tourette Syndrome

Introduction: Medicinal cannabis (MC) has potential therapeutic effects in Tourette Syndrome (TS), however there has been limited research in adolescent patients. This pilot study aimed to investigate the feasibility of conducting a randomized placebo-controlled crossover trial of MC in adolescents with TS. Method: This was a phase I/II double-blind, cross-over pilot study comparing MC with matched placebo in adolescents aged 12-18 years with TS. The active medication was Δ9-tetrahydrocannabinol (THC) 10 mg/mL and CBD 15 mg/mL in peppermint-flavored medium-chain triglyceride oil. The dose titration schedule was stratified into two participant weight bands: below 50 kg (max THC 10 mg/day) or ≥50 kg (max THC 20 mg/day). Each treatment phase lasted 10 weeks, with a 4-week washout period. Results: Ten adolescents were randomized (mean age 14.8 years, 50% male) and seven completed the full study protocol. Two adolescents discontinued due to adverse events (one on MC, one placebo) and one was lost to follow-up. The most common adverse event was dizziness (67%). There were no serious adverse events. Among actively enrolled participants, protocol adherence was excellent: study visits 100%, blood test completions 100%, and online questionnaire completion 97.6%. Medication adherence was acceptable in 63.6%. Parents reported a high degree of study design acceptability. On the Clinical Global Impression-Improvement scale, three participants were rated as much improved on MC compared with one on placebo at 10 weeks. Discussion: The findings suggest that the study protocol is feasible and acceptable to patients with TS and their families. A fully powered study is needed to evaluate the efficacy of MC in adolescent TS.

The CB1R of mPFC is involved in anxiety-like behavior induced by 0.8/2.65 GHz dual-frequency electromagnetic radiation

As mobile phones and communication base stations become more widespread, concerns have arisen regarding the potential risks of environmental exposure to multi-frequency electromagnetic radiation (EMR) and its effects on mental health. To address these concerns, our study established a dual-frequency EMR mouse model at 0.8/2.65 GHz to explore potential molecular mechanisms and intervention targets. Our results revealed that exposure to this dual-frequency EMR significantly induced anxiety-like behavior in mice. Molecular experiments further showed a significant decrease in cannabinoid receptor type 1 (CB1R) levels in the medial prefrontal cortex (mPFC) of the mice, along with a notable reduction in the endogenous cannabinoids 2-arachidonoylglycerol and anandamide. This led to a downregulation of the entire endocannabinoid system (ECS). Additional confirmation was obtained by overexpressing and knocking down CB1R in the mPFC. We found that increasing mPFC CB1R levels could effectively reduce anxiety-like behavior, while decreasing mPFC CB1R levels exacerbated it. Furthermore, we found dual-frequency EMR induced the change of ECS in the basolateral amygdala (BLA). Notably, female mice exhibited similar behavioral phenotypes and molecular mechanisms in response to dual-frequency EMR. In summary, our study demonstrates that anxiety induced by dual-frequency EMR is closely linked to the function of the ECS in the mPFC and BLA, and that CB1R expression in the mPFC plays a significant role in modulating emotional behavior in mice.

Unveiling the brain mechanism underlying depression: 12 Years of insights from bibliometric and visualization analysis

Depression is a common but serious mental health illness affected human's physiology and psychology. In contemporary times, neurophysiological research on depression has emerged as a prominent area of investigation, yet there remains a paucity of review elucidating the central mechanisms of depression in the brain. Consequently, we undertook a bibliometric analysis and visualization assessment to underscore recent advancements in research pertaining to the neural underpinnings of depression. By employing these methods, we have collected articles spanning the period from 2013 to 2024, shedding light on the latest insights into the brain mechanisms associated with depression. Bibliometric analysis found 16327 research papers in the field of brain mechanism underlying depression, overall showing a sustained growth trend. Through meticulous analysis of collected data on institutions and countries, authors, co-cited literature, keywords, etc., this paper humbly aims to tentatively identify future research hotspots and frontiers, hoping to modestly contribute to and stimulate further scholarly progress in the field.

CB1 receptor signaling: Linking neuroplasticity, neuronal types, and mental health outcomes

The endocannabinoid system (ECS) is crucial in the pathophysiology of mental disorders. Historically, cannabis has been utilized for centuries to mitigate symptoms of anxiety and depression; however, the precise role of cannabinoids in these conditions has only recently garnered extensive research attention. Despite the growing body of literature on the ECS and its association with mental health, several critical questions remain unresolved. This review primarily focuses on cannabinoid CB1 receptors (CB1R), providing an examination of their regulatory roles in states related to mental disorders. Evidence suggests that CB1R distribution occurs among various neuronal types, astrocytes, and subcellular membranes across multiple brain regions, potentially exhibiting both analogous and antagonistic effects. Additionally, various forms of stress have been shown to produce divergent impacts on CB1R signaling pathways. Furthermore, numerous CB1R agonists demonstrate biphasic, dose-dependent effects on anxiety and depression; specifically, low doses may exert anxiolytic effects, while higher doses can induce anxiogenic responses, a phenomenon observed in both rodent models and human studies. We also discuss the diverse underlying mechanisms that mediate these effects. We anticipate that this review will yield valuable insights into the role of CB1R in mental disorders and provide a framework for future research endeavors on CB1R and the ECS. This knowledge may ultimately inform therapeutic strategies aimed at alleviating symptoms associated with mental health conditions.

Cannabidiol/cannabidiolic acid-rich hemp (Cannabis sativa L.) extract attenuates cognitive impairments and glial activations in rats exposed to chronic stress

ETHNOPHARMACOLOGICAL RELEVANCE

Hemp (Cannabis sativa L.) is increasingly being recognized for its medicinal properties beside utilizing it for food, oil, and textile fibers. The high level of cannabidiol (CBD) content in hemp's flowers shows promising neuroprotective properties without causing psychotomimetic or addictive effects. Recently, products containing CBD and its precursor, cannabidiolic acid (CBDA), have been used to treat stress-related cognitive impairment. However, the therapeutic potential of hemp extract remains inadequately explored.

AIM OF THE STUDY

To investigate the effect of CBD/CBDA-rich hemp extract on learning and memory, neuroendocrine alterations, and hippocampal neuropathological changes in the chronic restraint stress model.

MATERIALS AND METHODS

Chronic restraint stress (CRS) was induced in male Wistar rats by immobilizing them in a restrainer for 6 h per day for 21 consecutive days. CBD/CBDA-rich hemp extract (10 and 30 mg/kg, intraperitoneal injection) was administered daily, 1 h before restraint. After the last day of CRS, behavioral tests for cognition were conducted using the Y-maze and object recognition tests. Serum corticosterone (CORT) levels were measured by ELISA. Histopathological changes, neuronal density, and the activation of microglia and astrocytes were visualized using cresyl violet and immunohistochemical staining.

RESULTS

A high dose of CBD/CBDA-rich hemp extract effectively ameliorated CRS-induced cognitive impairment and reversed HPA axis hyperactivity in CRS rats by reducing CORT levels and adrenal gland weight. Additionally, CBD/CBDA-rich hemp extract protected CRS-induced damage to hippocampal neurons. Further analysis showed that CBD/CBDA-rich hemp extract reduced specific markers of microglial activation (ionized calcium-binding adaptor molecule-1, Iba-1) and astrocytic structural protein (glial fibrillary acidic protein, GFAP) in CRS rats.

CONCLUSION

CBD/CBDA-rich hemp extracts remarkably reversed the stress-induced behavioral perturbations and hippocampal damage, suggesting its ameliorative effect on stress response.

A novel insight into the antidepressant effect of cannabidiol: possible involvement of the 5-HT1A, CB1, GPR55, and PPARγ receptors

BACKGROUND

Depression is a prevalent and disabling disorder that poses serious problems in mental health care, and rapid antidepressants are novel treatments for this disorder. Cannabidiol (CBD), a nonintoxicating phytocannabinoid, is thought to have therapeutic potential due to its important neurological and anti-inflammatory properties. Despite major advances in pharmacotherapy in experimental animals, the exact mechanism of antidepressant-like effects remains to be elucidated.

METHODS

In this paper, we review the current state of knowledge on the antidepressant properties of CBD in numerous experimental and clinical studies.

RESULTS

Accumulating evidence suggests that CBD has antidepressant properties in humans and animals with few side effects, suggesting that CBD may be a potential antidepressant. Furthermore, we discuss that CBD may therefore provide a potential treatment to exert antidepressant-like effects through various molecular targets, reducing inflammation, and enhancing neurogenesis.

CONCLUSIONS

Taken together with the growing popularity of CBD as a medicine, these findings extend the limited knowledge on the antidepressant effects of CBD. This potentially opens up new therapeutic means for the patients with depression.

Combined effects of cannabidiol and Δ9-tetrahydrocannabinol alleviate migraine-like symptoms in mice

BACKGROUND

The therapeutic use of cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) to treat migraine has been understudied. Using three mouse models, we examined the impact of CBD and THC on migraine-relevant behaviors triggered by: 1) calcitonin gene-related peptide (CGRP), 2) sodium nitroprusside (SNP), and 3) cortical spreading depolarization (CSD).

METHODS

Both male and female CD1 mice were treated with CBD (100 mg/kg) or THC (1 mg/kg) alone or in combinations of CBD (1, 30 or 100 mg/kg) and THC (1 mg/kg) prior to injection of CGRP or SNP. The mice were assessed for light aversion (photophobia), squint (non-evoked pain), and periorbital tactile hypersensitivity, as well as possible adverse effects. In a separate set of experiments, CSD events were optogenetically induced in familial hemiplegic migraine 1 (FHM1) mutant and wildtype littermates (WT) mice (C57BL/6 background), followed by grimace and motor assessments with and without combinations of CBD (30 or 100 mg/kg) and THC (1 mg/kg).

RESULTS

In CD1 mice, a 100:1 CBD:THC combination mitigated light aversion induced by CGRP and SNP in males and females. Rescue of CGRP- and SNP-induced squint was observed only in male mice with 100:1 CBD:THC. None of the treatments rescued periorbital tactile hypersensitivity in either sex. In FHM1 mutant and WT mice, the 100:1 CBD:THC ratio did not affect CSD characteristics but did reduce CSD-induced grimace features (i.e., head pain mimic). No adverse effects of any of the cannabinoid treatments were observed using cognitive, emotional, or motor tests.

CONCLUSIONS

A 100:1 ratio of CBD:THC has a beneficial effect on some of the most bothersome migraine-related symptoms in three mouse models. Our findings support a potential therapeutic efficacy of combined CBD and THC treatments.

Regional Structural-Functional Connectivity Coupling in Major Depressive Disorder Is Associated With Neurotransmitter and Genetic Profiles

BACKGROUND

Abnormalities in structural-functional connectivity (SC-FC) coupling have been identified globally in patients with major depressive disorder (MDD). However, investigations have neglected the variability and hierarchical distribution of these abnormalities across different brain regions. Furthermore, the biological mechanisms that underlie regional SC-FC coupling patterns are not well understood.

METHODS

We enrolled 182 patients with MDD and 157 healthy control participants and quantified the intergroup differences in regional SC-FC coupling. Extreme gradient boosting (XGBoost), support vector machine, and random forest models were constructed to assess the potential of SC-FC coupling as biomarkers for MDD diagnosis and symptom prediction. Then, we examined the link between changes in regional SC-FC coupling in patients with MDD, neurotransmitter distributions, and gene expression.

RESULTS

We observed increased regional SC-FC coupling in the default mode network (t337 = 3.233) and decreased coupling in the frontoparietal network (t337 = -3.471) in patients with MDD compared with healthy control participants. XGBoost (area under the receiver operating characteristic curve = 0.853), support vector machine (area under the receiver operating characteristic curve = 0.832), and random forest (p < .05) models exhibited good prediction performance. The alterations in regional SC-FC coupling in patients with MDD were correlated with the distributions of 4 neurotransmitters (p < .05) and expression maps of specific genes. These enriched genes were implicated in excitatory neurons, inhibitory neurons, cellular metabolism, synapse function, and immune signaling. These findings were replicated on 2 brain atlases.

CONCLUSIONS

This work enhances our understanding of MDD and paves the way for the development of additional targeted therapeutic interventions.

Acute cannabidiol treatment reverses behavioral impairments induced by embryonic valproic acid exposure in male mice

Cannabidiol (CBD), the major non-psychotomimetic compound of the Cannabis sativa plant, has shown promising effects in addressing various symptoms associated with autism spectrum disorder (ASD). This neurodevelopmental disorder typically impacts cognitive, behavioral, social communication, and motor skills domains. However, effective treatments for the wide range of symptoms associated with the disorder are limited and may trigger undesirable effects. Embryonic exposure to valproic acid (VPA, 500 mg/kg at 12° day embryonic age) in rodents is a consolidated environmental model for studying behavioral and molecular characteristics related to ASD. Therefore, this study aimed to evaluate whether acute CBD could reverse behavioral impairments in adult mice (eight weeks) exposed to VPA in the embryonic period in four distinct trials. In independent groups of animals, the following assays were conducted: I) Pre-Pulse Inhibition Test (PPI), II) Marble Burying, III) Social Interaction, IV) Actimeter Test, and V) Novel Object Recognition Test (NOR). In the PPI paradigm, mice exposed to VPA showed PPI impairment, and CBD (30 and 60 mg/kg) reversed this disruption. CBD (60 mg/kg) respectively decreased the number of buried marbles, improved social interaction time, but failed to reduce stereotyped-like movements in the VPA group. In NOR test CBD at both doses reversed the impairment in index of recognition induced in VPA group. These findings suggest that acute CBD administration can ameliorate behavioral impairments associated with ASD in a well-established animal model for studying this neurodevelopmental disorder.

Alginate-based microencapsulation as a strategy to improve the therapeutic potential of cannabidiolic acid

Cannabidiolic Acid (CBDA) is a promising natural compound with potent antioxidant, anti-inflammatory, and anti-emetic properties. Its antioxidant activity rivals that of vitamin E, while its anti-inflammatory effects are also remarkable. Additionally, CBDA has been shown to effectively reduce nausea and emetic attacks. As a more natural and water-soluble alternative to CBD, CBDA offers improved bioavailability and absorption. However, despite its promising potential, the development of effective CBDA delivery systems is still in its early stages. Among the various materials suitable for drug delivery, alginate is a widely used biopolymer due to its abundance and common availability in nature. This study aimed to develop an efficient CBDA delivery carrier using a microflow-dripping method to microencapsulate CBDA into alginate carriers (Alg-CBDA). The antioxidant, antimicrobial, and cytotoxicity properties of these Alg-CBDA capsules were then evaluated. Our results demonstrated that encapsulating CBDA within alginate capsules yielded a novel multifunctional biomaterial with prolonged antioxidant activity up to 72 h and antimicrobial activity against Gram-positive bacteria. Furthermore, the encapsulation process significantly reduced CBDA's cytotoxicity, broadening its potential applications. To our knowledge, this is the first study demonstrating the advantages of CBDA within a drug delivery framework.

Neuroprotective Actions of Cannabinoids in the Bovine Isolated Retina: Role of Hydrogen Sulfide

Both hydrogen sulfide and endocannabinoids can protect the neural retina from toxic insults under in vitro and in vivo conditions. Purpose: The aim of the present study was two-fold: (a) to examine the neuroprotective action of cannabinoids [methanandamide and 2-arachidonyl glycerol (2-AG)] against hydrogen peroxide (H2O2)-induced oxidative damage in the isolated bovine retina and (b) to evaluate the role of endogenously biosynthesized hydrogen sulfide (H2S) in the inhibitory actions of cannabinoids on the oxidative stress in the bovine retina. Methods: Isolated neural retinas from cows were exposed to oxidative damage using H2O2 (100 µM) for 10 min. When used, tissues were pretreated with methanandamide (1 nM-100 nM) and 2-AG (1-10 µM) for 30 min before a 10 min treatment with H2O2 (100 µM). In some experiments, retinas were pretreated with inhibitors of the biosynthesis of H2S [cystathionine β-synthase/cystathionine γ-lyase (CBS/CSE), aminooxyacetic acid, AOAA 30 µM, or 3-mercaptopyruvate sulfurtransferase (3MST), α-keto-butyric acid, KBA 1 mM] and the CB1-receptor antagonist, AM251 (100 nM) for 30 min before treatment with methanandamide (1 nM-100 µM). Enzyme immunoassay measurement of 8-epi PGF2α (8-isoprostane) levels was performed to assess lipid peroxidation in retinal tissues. Results: In the presence of H2O2 (100 µM), methanandamide (1 nM-100 µM) and 2-AG (1-10 µM) significantly (p < 0.001) blocked the H2O2-induced elevation in 8-isoprostane levels in the isolated bovine retina. In the presence of the CB1 antagonist AM251 (100 nM), the effect of methanandamide (1 nM) on the H2O2-induced 8-isoprostane production was significantly (p < 0.001) attenuated. While AOAA (30 µM) had no significant (p > 0.05) effect on the inhibition of H2O2-induced oxidative stress elicited by methanandamide, KBA (1 mM) reversed the neuroprotective action of methanandamide. Conclusions: The cannabinoids, methanandamide and 2-AG can prevent H2O2-induced oxidative stress in the isolated bovine retina. The neuroprotective actions of cannabinoids are partially dependent upon the activation of the CB1 receptors and endogenous production of H2S via the 3-MST/CAT pathway.

Cannabinoids and the male reproductive system: Implications of endocannabinoid signaling pathways

The escalating use and legalization of cannabis (marijuana) in the United States reflect shifting societal attitudes and growing awareness of its potential therapeutic benefits. Historically viewed as a harmful psychoactive substance, contemporary research has shown the intricate pharmacology of cannabis, with its diverse array of cannabinoids and their interactions with the endocannabinoid system. Among these cannabinoids, Δ9-tetrahydrocannabinol is the primary psychoactive component, characterized by its activation of cannabinoid receptors. The discovery of endocannabinoids, including anandamide and 2-arachidonoylglycerol, illuminated the body's innate cannabinoid signaling pathways and their involvement in several physiological processes. Endocannabinoids exert both positive and negative effects on the male reproductive system. They facilitate erectile function by modulating neurotransmission and vasodilation, offering potential therapeutic avenues for conditions like erectile dysfunction and prostatitis. However, chronic exogenous cannabinoid use, mainly of tetrahydrocannabinol, poses risks to male reproductive health by disrupting spermatogenesis, causing hormonal imbalances, and potentially influencing cancer cell proliferation. Understanding endocannabinoid signaling in the male reproductive system is essential to fully comprehend both the therapeutic benefits and potential drawbacks of cannabis use. Further research is required on these mechanisms, to provide insights that can guide clinical practice and policy-making regarding cannabis use. In this narrative review, we highlight the need for additional research into how cannabinoids affect male reproductive health, particularly with prolonged use. Investigating cannabinoids' impacts on spermatogenesis, hormonal balance, and cancer cell proliferation can provide valuable insights for healthcare professionals.

Hair and Saliva Endocannabinoid and Steroid Hormone Analysis by Liquid Chromatography Paired with Tandem Mass Spectrometry

Endocannabinoids are lipid neurotransmitters that play an important part in human health. Recent methods have found that quantification of endocannabinoids in hair and saliva samples is possible using liquid chromatography paired with tandem mass spectrometry (LC-MS/MS). This chapter describes two simple sample preparation methods that can be used to prepare hair and saliva samples for analysis using LC-MS/MS. Our LC-MS/MS method can be applied to both hair and saliva samples and is sufficiently sensitive for endocannabinoid, as well as steroid hormone, quantification in both of these sample matrices. This chapter provides a comprehensive description of how this can be achieved and provides tips and tricks for troubleshooting problems users may experience.

Cannabinoids: Role in Neurological Diseases and Psychiatric Disorders

An impact of legalization and decriminalization of marijuana is the gradual increase in the use of cannabis for recreational purposes, which poses a potential threat to society and healthcare systems worldwide. However, the discovery of receptor subtypes, endogenous endocannabinoids, and enzymes involved in synthesis and degradation, as well as pharmacological characterization of receptors, has led to exploration of the use of cannabis in multiple peripheral and central pathological conditions. The role of cannabis in the modulation of crucial events involving perturbed physiological functions and disease progression, including apoptosis, inflammation, oxidative stress, perturbed mitochondrial function, and the impaired immune system, indicates medicinal values. These events are involved in most neurological diseases and prompt the gradual progression of the disease. At present, several synthetic agonists and antagonists, in addition to more than 70 phytocannabinoids, are available with distinct efficacy as a therapeutic alternative in different pathological conditions. The present review aims to describe the use of cannabis in neurological diseases and psychiatric disorders.

In vivo multiplex imaging of dynamic neurochemical networks with designed far-red dopamine sensors

Neurochemical signals like dopamine (DA) play a crucial role in a variety of brain functions through intricate interactions with other neuromodulators and intracellular signaling pathways. However, studying these complex networks has been hindered by the challenge of detecting multiple neurochemicals in vivo simultaneously. To overcome this limitation, we developed a single-protein chemigenetic DA sensor, HaloDA1.0, which combines a cpHaloTag-chemical dye approach with the G protein-coupled receptor activation-based (GRAB) strategy, providing high sensitivity for DA, sub-second response kinetics, and an extensive spectral range from far-red to near-infrared. When used together with existing green and red fluorescent neuromodulator sensors, Ca2+ indicators, cAMP sensors, and optogenetic tools, HaloDA1.0 provides high versatility for multiplex imaging in cultured neurons, brain slices, and behaving animals, facilitating in-depth studies of dynamic neurochemical networks.

Growth hormone secretagogue receptor and cannabinoid receptor type 1 intersection in the mouse brain

The growth hormone secretagogue receptor (GHSR) and the cannabinoid receptor type 1 (CB1R) are G-protein coupled receptors highly expressed in the brain and involved in critical regulatory processes, such as energy homeostasis, appetite control, reward, and stress responses. GHSR mediates the effects of both ghrelin and liver-expressed antimicrobial peptide 2, while CB1R is targeted by cannabinoids. Strikingly, both receptors mediate their effects by acting on common brain areas and their individual roles have been well characterized. However, the potential for their co-expression in the same neuronal subsets remains largely unexplored. Here, we aim to map the cell populations where GHSR and CB1R might converge, hypothesizing that their co-expression in specific brain circuits could mediate integrated physiological responses. By utilizing two complementary labeling techniques-GHSR-eGFP mice and Fr-ghrelin labeling of GHSR+ cells-along with specific CB1R immunostaining, we sought to visualize and quantify potential areas of overlap. Also, we analyzed several cell RNA sequencing datasets to estimate the fraction of brain cells expressing both GPCRs and their phenotype. Our neuroanatomical studies revealed evident overlap of GHSR+ and CB1R+ signals in specific neuronal subsets mainly located in the cerebral cortex, hippocampus and the amygdala. Transcriptomic analysis revealed specific subsets of Ghsr+/Cnr1+ glutamatergic neurons in the hippocampus and amygdala, as well as different subtypes of Ghsr+/Cnr1+ neurons in the midbrain, hypothalamus, pons, and medulla. Thus, we revealed that GHSR and CB1R interact differentially across specific regions of the mouse brain, providing new insights into how these receptors' actions are integrated. Current findings may open new avenues for dual therapeutic interventions in metabolic disorders, obesity, and psychiatric conditions.

Effects of psychedelics on neurogenesis and broader neuroplasticity: a systematic review

In the mammalian brain, new neurons continue to be generated throughout life in a process known as adult neurogenesis. The role of adult-generated neurons has been broadly studied across laboratories, and mounting evidence suggests a strong link to the HPA axis and concomitant dysregulations in patients diagnosed with mood disorders. Psychedelic compounds, such as phenethylamines, tryptamines, cannabinoids, and a variety of ever-growing chemical categories, have emerged as therapeutic options for neuropsychiatric disorders, while numerous reports link their effects to increased adult neurogenesis. In this systematic review, we examine studies assessing neurogenesis or other neurogenesis-associated brain plasticity after psychedelic interventions and aim to provide a comprehensive picture of how this vast category of compounds regulates the generation of new neurons. We conducted a literature search on PubMed and Science Direct databases, considering all articles published until January 31, 2023, and selected articles containing both the words "neurogenesis" and "psychedelics". We analyzed experimental studies using either in vivo or in vitro models, employing classical or atypical psychedelics at all ontogenetic windows, as well as human studies referring to neurogenesis-associated plasticity. Our findings were divided into five main categories of psychedelics: CB1 agonists, NMDA antagonists, harmala alkaloids, tryptamines, and entactogens. We described the outcomes of neurogenesis assessments and investigated related results on the effects of psychedelics on brain plasticity and behavior within our sample. In summary, this review presents an extensive study into how different psychedelics may affect the birth of new neurons and other brain-related processes. Such knowledge may be valuable for future research on novel therapeutic strategies for neuropsychiatric disorders.

Structural mechanism of CB1R binding to peripheral and biased inverse agonists

The cannabinoid receptor 1 (CB1R) regulates synaptic transmission in the central nervous system, but also has important roles in the peripheral organs controlling cellular metabolism. While earlier generations of brain penetrant CB1R antagonists advanced to the clinic for their effective treatment of obesity, such molecules were ultimately shown to exhibit negative effects on central reward pathways that thwarted their further therapeutic development. The peripherally restricted CB1R inverse agonists MRI-1867 and MRI-1891 represent a new generation of compounds that retain the metabolic benefits of CB1R inhibitors while sparing the negative psychiatric effects. To understand the mechanism of binding and inhibition of CB1R by peripherally restricted antagonists, we developed a nanobody/fusion protein strategy for high-resolution cryo-EM structure determination of the GPCR inactive state, and used this method to determine structures of CB1R bound to either MRI-1867 or MRI-1891. These structures reveal how these compounds retain high affinity and specificity for CB1R's hydrophobic orthosteric site despite incorporating polar functionalities that lead to peripheral restriction. Further, the structure of the MRI-1891 complex along with accompanying molecular dynamics simulations shows how differential engagement with transmembrane helices and the proximal N-terminus can propagate through the receptor to contribute to biased inhibition of β-arrestin signaling.

Medical cannabis: From research breakthroughs to shifting public perceptions and ensuring safe use

The landscape of medical cannabis has evolved dramatically over the past few decades. Once stigmatized and illegal in most parts of the world, cannabis is now recognized for its potential therapeutic benefits, supported by an expanding body of scientific research. However, the transition from prohibition to medical recognition is shaped by complex interactions among scientific advancements, public perception and regulatory frameworks for its legalization. This review examines the recent breakthroughs in medical cannabis research, explores the shifting public perceptions and the stigma associated with its use and discusses strategies for enhancing the safety of medical cannabis. We also synthesize the connections between scientific research, public perception and safety considerations in the uses of medical cannabis, providing a comprehensive understanding of how these elements influence each other and shape the future of medical cannabis use for patient adherence.

Microglial cannabinoid receptor type II stimulation improves cognitive impairment and neuroinflammation in Alzheimer's disease mice by controlling astrocyte activation

Alzheimer's disease (AD) is the most common form of dementia and is characterized by the accumulation of amyloid β (Aβ) and phosphorylated tau. Neuroinflammation, mainly mediated by glial activation, plays an important role in AD progression. Although there is growing evidence for the anti-neuroinflammatory and neuroprotective effects of the cannabinoid system modulation, the detailed mechanism remains unclear. To address these issues, we analyzed the expression levels of cannabinoid receptor type II (Cnr2/Cb2) in AppNL-G-F/NL-G-F mice and human AD precuneus, which is vulnerable to amyloid deposition in AD, and the effects of JWH 133, a selective CB2 agonist, on neuroinflammation in primary glial cells and neuroinflammation and cognitive impairment in AppNL-G-F/NL-G-F mice. The levels of Cnr2/Cb2 were upregulated in microglia isolated from the cerebral cortex of AppNL-G-F/NL-G-F mice. CNR2 expression was also increased in RNAs derived from human precuneus with advanced AD pathology. Chronic oral administration of JWH 133 significantly ameliorated the cognitive impairment of AppNL-G-F/NL-G-F mice without neuropsychiatric side effects. Microglia and astrocyte mRNAs were directly isolated from the mouse cerebral cortex by magnetic-activated cell sorting, and the gene expression was determined by quantitative PCR. JWH 133 administration significantly decreased reactive astrocyte markers and microglial C1q, an inducer for the reactive astrocytes in AppNL-G-F/NL-G-F mice. In addition, JWH133 administration inhibited the expression of p-STAT3 (signal transducer and activator of transcription 3) in astrocytes in AppNL-G-F/NL-G-F mice. Furthermore, JWH 133 administration suppressed dystrophic presynaptic terminals surrounding amyloid plaques. In conclusion, stimulation of microglial CB2 ameliorates cognitive dysfunction in AppNL-G-F/NL-G-F mice by controlling astrocyte activation and inducing beneficial neuroinflammation, and our study has implications that CB2 may represent an attractive therapeutic target for the treatment of AD and perhaps other neurodegenerative diseases involving neuroinflammation.

LY-2183240 enhances reward-seeking behavior with inducing neuronal excitation and early apoptosis in mouse

Cannabinoids interact with cannabinoid receptors, influencing diverse central nervous system (CNS) and peripheral functions, including anxiety, depression, and cognition. CB1 and CB2 receptors modulate signaling cascades via G-protein coupling, with anandamide acting as an endogenous ligand for CB1 receptors. LY-2183240, a putative endocannabinoid transport blocker, elevates brain anandamide levels, showing therapeutic potential in pain management and alcohol-related behaviors. LY-2183240 enhances neuronal excitability and is classified as a new psychoactive substance (NPS). However, its precise cellular mechanisms within the CNS remain poorly understood. In this study, the effect of LY-2183240 on cortical neurons and reward-seeking behavior is investigated. Our results indicate enhanced neuronal excitability and reward-seeking behavior induction by LY-2183240, shedding light on its pharmacological profile and NPS-associated risks. Our research underscores the importance of further understanding the cellular mechanisms of LY-2183240 to inform regulatory efforts and mitigate public health risks.

Early life stress induces decreased expression of CB1R and FAAH and epigenetic changes in the medial prefrontal cortex of male rats

Several studies in both animal models and in humans have provided substantial evidence that early life stress (ELS) induces long-term changes in behavior and brain function, making it a significant risk factor in the aetiology of various mental disorders, including anxiety and depression. In this study, we tested the hypothesis that ELS in male rats (i) leads to increased anxiety and depressive-like symptoms; and (ii) that these behavioral changes are associated with functional alterations in the endocannabinoid system of the medial prefrontal cortex (mPFC). We further assessed whether the predicted changes in the gene expression of two key components of the endocannabinoid system, cannabinoid receptor 1 (CB1R) and the fatty acid amide hydrolase (FAAH), are regulated by epigenetic mechanisms. Behavioral profiling revealed that the proportion of behaviorally affected animals was increased in ELS exposed male rats compared to control animals, specifically showing symptoms of anhedonia and impaired social behavior. On the molecular level we observed a decrease in CB1R and FAAH mRNA expression in the mPFC of adult ELS exposed animals. These gene expression changes were accompanied by reduced global histone 3 acetylation in the mPFC, while no significant changes in DNA methylation and no significant changes of histone-acetylation at the promoter regions of the analyzed genes were detected. Taken together, our data provide evidence that ELS induces a long-term reduction of CB1R and FAAH expression in the mPFC of adult male rats, which may partially contribute to the ELS-induced changes in adult socio-emotional behavior.

Antidepressant-like Effects of Cannabis sativa L. Extract in an Lipopolysaccharide Model: Modulation of Mast Cell Activation in Deep Cervical Lymph Nodes and Dura Mater

BACKGROUND

Lipopolysaccharide (LPS)-induced neuroinflammation is a well-established model for studying depression-like behavior, driven by pro-inflammatory cytokines such as TNF-α and IL-1β. Mast cells (MCs) contribute to neuroinflammation by releasing mediators that exacerbate depressive-like symptoms. This study evaluates the antidepressant-like and anti-inflammatory effects of Cannabis sativa L. inflorescence extract (CSL) in an LPS-induced neuroinflammation model.

METHODS

Male C57BL/6 mice were intraperitoneally injected with CSL at doses of 10, 20, and 30 mg/kg, 30 min prior to LPS (0.83 mg/kg) administration. Depressive behaviors were assessed using the sucrose preference test (SPT), tail suspension test (TST), and forced swimming test (FST). The neutrophil-to-lymphocyte ratio (NLR) was measured to assess systemic inflammation. Cytokine levels in the prefrontal cortex (PFC) were measured, and mast cell degranulation in the lymph nodes and dura mater was analyzed histologically (approval number: WKU24-64).

RESULTS

CSL significantly improved depressive-like behaviors and decreased the NLR, indicating reduced systemic inflammation. CSL also significantly reduced TNF-α and IL-1β levels in the PFC. Furthermore, CSL inhibited MC degranulation in the deep cervical lymph nodes and dura mater, with the strongest effects observed at 30 mg/kg.

CONCLUSIONS

CSL demonstrated antidepressant-like and anti-inflammatory effects in an LPS-induced neuroinflammation model, likely through the modulation of cytokine expression and mast cell activity. These results suggest the potential of CSL as a therapeutic option for treating inflammation-related depression.

Interplay between cannabinoids and the neuroimmune system in migraine

Migraine is a common and complex neurological disorder that has a high impact on quality of life. Recent advances with drugs that target the neuropeptide calcitonin gene-related peptide (CGRP) have helped, but treatment options remain insufficient. CGRP is released from trigeminal sensory fibers and contributes to peripheral sensitization, perhaps in part due to actions on immune cells in the trigeminovascular system. In this review, we will discuss the potential of cannabinoid targeting of immune cells as an innovative therapeutic target for migraine treatment. We will cover endogenous endocannabinoids, plant-derived phytocannabinoids and synthetically derived cannabinoids. The focus will be on six types of immune cells known to express multiple cannabinoid receptors: macrophages, monocytes, mast cells, dendritic cells, B cells, and T cells. These cells also contain receptors for CGRP and as such, cannabinoids might potentially modulate the efficacy of current CGRP-targeting drugs. Unfortunately, to date most studies on cannabinoids and immune cells have relied on cell cultures and only a single preclinical study has tested cannabinoid actions on immune cells in a migraine model. Encouragingly, in that study a synthetically created stable chiral analog of an endocannabinoid reduced meningeal mast cell degranulation. Likewise, clinical trials evaluating the safety and efficacy of cannabinoid-based therapies for migraine patients have been limited but are encouraging. Thus, the field is at its infancy and there are significant gaps in our understanding of the impact of cannabinoids on immune cells in migraine. Future research exploring the interactions between cannabinoids and immune cells could lead to more targeted and effective migraine treatments.

Emerging roles of cannabinoid receptor CB2 receptor in the central nervous system: therapeutic target for CNS disorders

RATIONALE

The endocannabinoid system (ECS) belongs to the G protein-coupled receptor family of cell membranes and is associated with neuropsychiatric conditions, and neurodegenerative diseases. Cannabinoid 2 receptors (CB2) are expressed in the central nervous system (CNS) on microglia and subgroups of neurons and are involved in various behavioural processes via immunological and neural regulation.

OBJECTIVE

The objective of this paper is to summarize and explore the impact of CB2 receptors on neuronal modulation, their involvement in various neurological disorders, and their influence on mood, behavior, and cognitive function.

RESULTS

The activation of CB2 appears to protect the brain and its functions from damage under neuroinflammatory actions, making it an attractive target in a variety of neurological conditions such as Parkinson's disease (PD), multiple sclerosis (MS), Alzheimer's disease (AD), and Huntington's disease (HD). During inflammation, there is an overexpression of CB2 receptors, and CB2 agonists show a strong anti-inflammatory effect. These results have sparked interest in the CB2 receptors as a potential target for neurodegenerative and neuroinflammatory disease treatment.

CONCLUSION

In conclusion, CB2 receptors signalling shows promise for developing targeted interventions that could positively affect both immune and neuronal functions, ultimately influencing behavioral outcomes in both health and disease.

Medical marijuana in the treatment of cancer-associated symptoms

OBJECTIVE

Previous cancer studies have indicated that medical marijuana addresses a significant unmet need, namely chronic pain treatment and conferring oncology supportive care. However, the clinical research evaluating medical marijuana is preliminary and requires further consideration.

DATA SOURCES

We conducted a PubMed search primarily comprising retrospective and prospective studies, systematic reviews, and randomized clinical trials (RCTs) from approximately 2020-2023. The search included specific terms that incorporated medical marijuana, cancer treatment, cancer-related symptoms, pain management, and side effects.

DATA SUMMARY

A total of 40 studies were included in the review, many of which were either of acceptable or good quality. Select investigations indicated that medical marijuana was associated with decreased overall pain levels and improvements in nausea and vomiting. Alternatively, the results from RCTs have found that the benefits from a placebo were equivalent to medical marijuana in both the treatment of cancer-related pain and providing an opioid-sparing effect.

CONCLUSIONS

Despite the potential cancer-related benefits derived from medical marijuana, the study design and results for many of the investigations on which the evidence is based, were neither uniform nor conducted via RCTs; hence, the efficacy and appropriateness of medical marijuana in treating cancer-related conditions remain indeterminate.

DNA methylation at cannabinoid type 1 and dopamine D2 receptor genes in saliva samples of psychotic subjects: Is there an effect of Cannabis use?

Psychosis is a characterizing feature of many mental disorders that dramatically affects human thoughts and perceptions, influencing the ability to distinguish between what is real and what is not. Both genetic and environmental factors, such as stressful events or drug use, play a pivotal role in the development of symptomatology and therefore changes in the epigenome may be of relevance in modeling a psychotic phenotype. According to the well-documented dysregulation of endocannabinoid and dopaminergic system genes in schizophrenia, we investigated DNA methylation cannabinoid type 1 receptor (CNR1) and dopamine D2 receptor (DRD2) genes in saliva samples from psychotic subjects using pyrosequencing. The epigenetic mark was significantly higher and directly correlated for both genes in psychotic subjects compared to healthy controls. We also showed that these DNA methylation levels were lower in psychotic subjects reporting current delta-9-tetrahydrocannabinol (THC) consumption, a well-known risk factor for developing psychosis throughout the lifespan, resembling those of controls at least for the DRD2 gene. Overall, our data confirm the key role of CNR1 and DRD2 gene regulation in psychosis and suggest DNA methylation levels at specific CpG sites as potential biomarkers, but just in those psychotic subjects not consuming THC.

The Modulatory Effects and Therapeutic Potential of Cannabidiol in the Gut

Cannabidiol (CBD) is a major non-psychotropic phytocannabinoid that exists in the Cannabis sativa plant. CBD has been found to act on various receptors, including both cannabinoid and non-cannabinoid receptors. In addition, CBD has antioxidant effects that are independent of receptors. CBD has demonstrated modulatory effects at different organ systems, such as the central nervous system, immune system, and the gastrointestinal system. Due to its broad effects within the body and its safety profile, CBD has become a topic of therapeutic interest. This literature review summarizes previous research findings with regard to the effect of CBD on the gastrointestinal (GI) system, including its effects at the molecular, cellular, organ, and whole-body levels. Both pre-clinical animal studies and human clinical trials are reviewed. The results of the studies included in this literature review suggest that CBD has significant impact on intestinal permeability, the microbiome, immune cells and cytokines. As a result, CBD has been shown to have therapeutic potential for GI disorders such as inflammatory bowel disease (IBD). Furthermore, through interactions with the gut, CBD may also be helpful in the treatment of disorders outside the GI system, such as non-alcoholic liver disease, postmenopausal disorders, epilepsy, and multiple sclerosis. In the future, more mechanistic studies are warranted to elucidate the detailed mechanisms of action of CBD in the gut. In addition, more well-designed clinical trials are needed to explore the full therapeutic potential of CBD on and through the gut.

Local activation of CB1 receptors by synthetic and endogenous cannabinoids dampens burst firing mode of reticular thalamic nucleus neurons in rats under ketamine anesthesia

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.

Involvement of the TRPV1 receptor and the endocannabinoid system in schizophrenia

BACKGROUND

Schizophrenia (SCZ) is a severe mental disorder, but its pathogenesis is still unknown, and its clinical treatment effect is very limited. Transient receptor potential vanilloid 1 (TRPV1) channel and the Endocannabinoid System (ECS)have been confirmed to be involved in the pathogenesis of SCZ, although their actions have not been fully clarified yet. The objective is to examine TRPV1 and ECS expression in the blood of schizophrenia patients and investigate their correlation with disease severity.

METHODS

This is a cross-sectional investigation. Peripheral blood samples were gathered from normal controls (NC, n=37), as well as individuals with schizophrenia, including first episode (n=30) and recurrent (n=30) cases. We employed western blot and ELISA techniques to quantify TRPV1, cannabinoid receptors 1(CB1), anandamide (AEA), and 2-arachidonoylglycerol (2-AG), and assess the severity of the patient's symptoms by means of the PANSS scale.

RESULTS

Compared to NC, TRPV1 levels showed a noticeable decrease in both first episode schizophrenia (f-SCZ group) and recurrent schizophrenia (r-SCZ group) subjects. Additionally, CB1 levels appeared increased in f-SCZ group. Furthermore, 2-AG levels were found to be elevated in both f-SCZ group and r-SCZ group compared to NC, whereas AEA levels were decreased in f-SCZ group but increased in r-SCZ group. Moreover, among schizophrenia patients, TRPV1 demonstrated a negative correlation with negative symptoms. Within r-SCZ subjects, CB1 displayed a negative correlation with relapse number, while 2-AG showed a correlation in the opposite direction.

CONCLUSIONS

This study provides initial clinical evidence of changed TRPV1 expression in schizophrenia, potentially linked to negative symptoms. These results suggest a possible dysfunction of TRPV1 and the endocannabinoid system (ECS), which might offer new avenues for medical interventions.

Alterations to sphingolipid metabolism from antipsychotic administration in healthy volunteers are restored following the use of cannabidiol

Randomized clinical trials substantiate cannabidiol (CBD) as a next-generation antipsychotic, effective in alleviating positive and negative symptoms associated with psychosis, while minimising the adverse effects seen with established treatments. Although the mechanisms remain debated, CBD is known to induce drug-responsive changes in lipid-based retrograde neurotransmitters. Lipid aberrations are also frequently observed with antipsychotics, which may contribute to their efficacy or increase the risk of undesirables, including metabolic dysfunction, obesity and dyslipidaemia. Our study investigated CBD's impact following lipid responses triggered by interaction with second-generation antipsychotics (SGA) in a randomized phase I safety study. Untargeted mass spectrometry assessed the lipidomic profiles of human sera, collected from 38 healthy volunteers. Serum samples were obtained prior to commencement of any medication (t = 0), 3 days after consecutive administration of one of the five, placebo-controlled, treatment arms designed to achieve steady-state concentrations of each SGA (amisulpride, 150 mg/day; quetiapine, 300 mg/day; olanzapine 10 mg/day; risperidone, 3 mg/day), and after six successive days of SGA treatment combined with CBD (800 mg/day). Receiver operating characteristics (ROC) refined 3712 features to a putative list of 15 lipids significantly altered (AUC > 0.7), classified into sphingolipids (53 %), glycerolipids (27 %) and glycerophospholipids (20 %). Targeted mass spectrometry confirmed reduced sphingomyelin and ceramide levels with antipsychotics, which mapped along their catabolic pathway and were restored by CBD. These sphingolipids inversely correlated with body weight after olanzapine, quetiapine, and risperidone treatment, where CBD appears to have arrested or attenuated these effects. Herein, we propose CBD may alleviate aberrant sphingolipid metabolism and that further investigation into sphingolipids as markers for monitoring side effects of SGAs and efficacy of CBD is warranted.

Nicotine use during late adolescence and young adulthood is associated with changes in hippocampal volume and memory performance

Background

With the advent of electronic nicotine delivery systems, the use of nicotine and tobacco products (NTPs) among adolescents and young adults remains high in the US. Use of e-cigarettes additionally elevates the risk of problematic use of other substances like cannabis, which is often co-used with NTPs. However, their effects on brain health, particularly the hippocampus, and cognition during this neurodevelopmental period are poorly understood.

Methods

Healthy late adolescents/young adults (N = 223) ages 16-22 completed a structural MRI to examine right and left hippocampal volumes. Memory was assessed with the NIH Toolbox Picture Sequence Memory Test (PSMT) and Rey Auditory Verbal Learning Test (RAVLT). Cumulative 6-month NTP and cannabis episodes were assessed and modeled continuously on hippocampal volumes. Participants were then grouped based on 6-month NTP use to examine relationships with the hippocampus and memory: current users (CU) endorsed weekly or greater use; light/abstinent users (LU) endorsed less than weekly; and never users (NU).

Results

NTP use predicted larger hippocampal volumes bilaterally while cannabis use had no impact nor interacted with NTP use. For memory, larger left hippocampal volumes were positively associated with PSMT performance, RAVLT total learning, short delay and long delay recall for the NU group. In contrast, there was a negative relationship between hippocampal volumes and performances for LU and CU groups. No differences were detected between NTP-using groups.

Conclusion

These results suggest that the hippocampus is sensitive to NTP exposure during late adolescence/young adulthood and may alter typical hippocampal morphometry in addition to brain-behavior relationships underlying learning and memory processes.

Elucidating genetic and molecular basis of altered higher-order brain structure-function coupling in major depressive disorder

Previous studies have shown that major depressive disorder (MDD) patients exhibit structural and functional impairments, but few studies have investigated changes in higher-order coupling between structure and function. Here, we systematically investigated the effect of MDD on higher-order coupling between structural connectivity (SC) and functional connectivity (FC). Each brain region was mapped into embedding vector by the node2vec algorithm. We used support vector machine (SVM) with the brain region embedding vector to distinguish MDD patients from health controls (HCs) and identify the most discriminative brain regions. Our study revealed that MDD patients had decreased higher-order coupling in connections between the most discriminative brain regions and local connections in rich-club organization and increased higher-order coupling in connections between the ventral attentional network and limbic network compared with HCs. Interestingly, transcriptome-neuroimaging association analysis demonstrated the correlations between regional rSC-FC coupling variations between MDD patients and HCs and α/β-hydrolase domain-containing 6 (ABHD6), β 1,3-N-acetylglucosaminyltransferase-9(β3GNT9), transmembrane protein 45B (TMEM45B), the correlation between regional dSC-FC coupling variations and retinoic acid early transcript 1E antisense RNA 1(RAET1E-AS1), and the correlations between regional iSC-FC coupling variations and ABHD6, β3GNT9, katanin-like 2 protein (KATNAL2). In addition, correlation analysis with neurotransmitter receptor/transporter maps found that the rSC-FC and iSC-FC coupling variations were both correlated with neuroendocrine transporter (NET) expression, and the dSC-FC coupling variations were correlated with metabotropic glutamate receptor 5 (mGluR5). Further mediation analysis explored the relationship between genes, neurotransmitter receptor/transporter and MDD related higher-order coupling variations. These findings indicate that specific genetic and molecular factors underpin the observed disparities in higher-order SC-FC coupling between MDD patients and HCs. Our study confirmed that higher-order coupling between SC and FC plays an important role in diagnosing MDD. The identification of new biological evidence for MDD etiology holds promise for the development of innovative antidepressant therapies.

Peripheral endocannabinoids in major depressive disorder and alcohol use disorder: a systematic review

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.

Tobacco Quitline Callers Who Use Cannabis and Their Likelihood of Quitting Cigarette Smoking

INTRODUCTION

Cigarette smoking continues to decline in the U.S., but cannabis use is increasing. Many people who smoke cigarettes also use cannabis. This study examines the characteristics of persons who co-use and those who do not co-use and the likelihood of quitting cigarettes for callers to Kick It California, a large state tobacco quitline.

METHODS

Data were examined from Kick It California callers from January 2020 through December 2023 (N=45,151), including those from a subgroup randomly sampled and reached for evaluation at 7 months after quitline enrollment (n=3,545). The rate of cigarette smoking cessation at 7 months after enrollment for people who co-use cannabis was compared with that for people who do not. Analyses started in 2023 and concluded in January 2024.

RESULTS

More than a quarter (27.2%) of Kick It California callers co-used cannabis. They were more likely to be male, to be younger, and to have a mental health condition than those who did not. Those who co-use cannabis and those who do not have similar rates of receiving quitline counseling or using Food and Drug Administration-approved cessation aids. Controlled for effects of personal characteristics and use of smoking-cessation services, people who co-use cannabis were less likely to quit cigarette smoking 7 months after enrollment (23.2% vs 28.9%; p<0.001). Among those who co-use, 42.9% intended to quit using cannabis in the next 30 days.

CONCLUSIONS

A substantial percentage of tobacco quitline callers use cannabis. Those who do co-use quit cigarette smoking at a lower rate than those who do not. Over 40% of people who co-use reported intention to quit cannabis, making tobacco quitlines a rich environment to learn about people who co-use and develop strategies for intervention.

True or false? Alzheimer's disease is type 3 diabetes: Evidences from bench to bedside

Globally, Alzheimer's disease (AD) is the most widespread chronic neurodegenerative disorder, leading to cognitive impairment, such as aphasia and agnosia, as well as mental symptoms, like behavioral abnormalities, that place a heavy psychological and financial burden on the families of the afflicted. Unfortunately, no particular medications exist to treat AD, as the current treatments only impede its progression.The link between AD and type 2 diabetes (T2D) has been increasingly revealed by research; the danger of developing both AD and T2D rises exponentially with age, with T2D being especially prone to AD. This has propelled researchers to investigate the mechanism(s) underlying this connection. A critical review of the relationship between insulin resistance, Aβ, oxidative stress, mitochondrial hypothesis, abnormal phosphorylation of Tau protein, inflammatory response, high blood glucose levels, neurotransmitters and signaling pathways, vascular issues in AD and diabetes, and the similarities between the two diseases, is presented in this review. Grasping the essential mechanisms behind this detrimental interaction may offer chances to devise successful therapeutic strategies.

The role of fatty acid-binding protein 5 and 7 on locomotor, anxiety and social behavior: Interaction with NMDA signaling

The endocannabinoid system has been shown to be a powerful mediator of anxiety, learning and memory, as well as nociception behaviors. Exogenous cannabinoids like delta-9-tetrahydrocannabinol mimic the naturally occurring endogenous cannabinoids found in the mammalian central and peripheral nervous system. The hydrophobic properties of endocannabinoids mean that these psychoactive compounds require help with cellular transport. A family of lipid intracellular carriers called fatty acid-binding proteins (FABPs) can bind to endocannabinoids. Pharmacological inhibition or genetic deletion of FABP subtypes 5 and 7 elevates whole-brain anandamide (AEA) levels, a type of endocannabinoid. This study examined locomotor behavior, anxiety-like behavior, and social behavior in FABP5-/- and FABP7-/- mice. Furthermore, we measured N-methyl-D-aspartate (NMDA) receptor levels in the brain to help identify potential underlying mechanisms related to the behavioral findings. Results showed that both male and female FABP5-/- mice exhibited significantly lower activity when compared with both FABP5/7+/+ (control) and FABP7-/-. For social behavior, male, but not female, FABP5-/- mice spent more time interacting with novel mice compared with controls (FABP5/7+/+) and FABP7-/- mice. No significant difference was found for anxiety-like behavior. Results from the NMDA autoradiography revealed [3H] MK-801 binding to be significantly increased within sub-regions of the striatum in FABP7-/- compared with control. In summary, these results show that FABP5 deficiency plays a significant role in locomotion activity, exploratory behavior, as well as social interaction. Furthermore, FABP7 deficiency is shown to play an important role in NMDA receptor expression, while FABP5 does not.

Examination of the Effect of Dimethyl Trisulfide in Acute Stress Mouse Model with the Potential Involvement of the TRPA1 Ion Channel

Polysulfides are endogenously produced in mammals and generally associated with protective functions. Our aim was to investigate the effect of dimethyl trisulfide (DMTS) in a mouse model of acute stress. DMTS activates transient receptor potential ankyrin 1 (TRPA1) channels and leads to neuropeptide release, potentially that of substance P (SP). We hypothesize that DMTS might inhibit the degrading enzymes of endocannabinoids, so this system was also investigated as another possible pathway for mediating the effects of DMTS. Trpa1 gene wild-type (WT) and knockout (KO) mice were used to confirm the role of the TRPA1 ion channel in mediating the effects of DMTS. C57BL/6J, NK1 gene KO, and Tac1 gene KO mice were used to evaluate the effect of DMTS on the release and expression of SP. Some C57BL/6J animals were treated with AM251, an inhibitor of the cannabinoid CB1 receptor, to elucidate the role of the endocannabinoid system in these processes. Open field test (OFT) and forced swim test (FST) were performed in each mouse strain. A tail suspension test (TST) was performed in Trpa1 WT and KO animals. C-FOS immunohistochemistry was carried out on Trpa1 WT and KO animals. The DMTS treatment increased the number of highly active periods and decreased immobility time in the FST in WT animals, but had no effect on the Trpa1 KO mice. The DMTS administration induced neuronal activation in the Trpa1 WT mice in the stress-related brain areas, such as the locus coeruleus, dorsal raphe nucleus, lateral septum, paraventricular nucleus of the thalamus, and paraventricular nucleus of the hypothalamus. DMTS may have a potential role in the regulation of stress-related processes, and the TRPA1 ion channel may also be involved in mediating the effects of DMTS. DMTS can be an ideal candidate for further study as a potential remedy for stress-related disorders.

Putative Pharmacological Depression and Anxiety-Related Targets of Calcitriol Explored by Network Pharmacology and Molecular Docking

Depression and anxiety disorders, prevalent neuropsychiatric conditions that frequently coexist, limit psychosocial functioning and, consequently, the individual's quality of life. Since the pharmacological treatment of these disorders has several limitations, the search for effective and secure antidepressant and anxiolytic compounds is welcome. Vitamin D has been shown to exhibit neuroprotective, antidepressant, and anxiolytic properties. Therefore, this study aimed to explore new molecular targets of calcitriol, the active form of vitamin D, through integrated bioinformatic analysis. Calcitriol targets were predicted in SwissTargetPrediction server (2019 version). The disease targets were collected by the GeneCards database searching the keywords "depression" and "anxiety". Gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the intersections of targets. Network analyses were carried out using GeneMania server (2023 version) and Cytoscape (V. 3.9.1.) software. Molecular docking predicted the main targets of the network and Ligplot predicted the main intermolecular interactions. Our study showed that calcitriol may interact with multiple targets. The main targets found are the vitamin D receptor (VDR), histamine H3 receptor (H3R), endocannabinoid receptors 1 and 2 (CB1 and CB2), nuclear receptor NR1H3, patched-1 (PTCH1) protein, opioid receptor NOP, and phosphodiesterase enzymes PDE3A and PDE5A. Considering the role of these targets in the pathophysiology of depression and anxiety, our findings suggest novel putative mechanisms of action of vitamin D as well as new promising molecular targets whose role in these disorders deserves further investigation.

Cutaneous Wound Healing and the Effects of Cannabidiol

Cutaneous wounds, both acute and chronic, begin with loss of the integrity, and thus barrier function, of the skin. Surgery and trauma produce acute wounds. There are 22 million surgical procedures per year in the United States alone, based on data from the American College of Surgeons, resulting in a prevalence of 6.67%. Acute traumatic wounds requiring repair total 8 million per year, 2.42% or 24.2 per 1000. The cost of wound care is increasing; it approached USD 100 billion for just Medicare in 2018. This burden for wound care will continue to rise with population aging, the increase in metabolic syndrome, and more elective surgeries. To heal a wound, an orchestrated, evolutionarily conserved, and complex series of events involving cellular and molecular agents at the local and systemic levels are necessary. The principal factors of this important function include elements from the neurological, cardiovascular, immune, nutritional, and endocrine systems. The objectives of this review are to provide clinicians engaged in wound care and basic science researchers interested in wound healing with an updated synopsis from recent publications. We also present data from our primary investigations, testing the hypothesis that cannabidiol can alter cutaneous wound healing and documenting their effects in wild type (C57/BL6) and db/db mice (Type 2 Diabetes Mellitus, T2DM). The focus is on the potential roles of the endocannabinoid system, cannabidiol, and the important immune-regulatory wound cytokine IL-33, a member of the IL-1 family, and connective tissue growth factor, CTGF, due to their roles in both normal and abnormal wound healing. We found an initial delay in the rate of wound closure in B6 mice with CBD, but this difference disappeared with time. CBD decreased IL-33 + cells in B6 by 70% while nearly increasing CTGF + cells in db/db mice by two folds from 18.6% to 38.8% (p < 0.05) using a dorsal wound model. We review the current literature on normal and abnormal wound healing, and document effects of CBD in B6 and db/db dorsal cutaneous wounds. CBD may have some beneficial effects in diabetic wounds. We applied 6-mm circular punch to create standard size full-thickness dorsal wounds in B6 and db/db mice. The experimental group received CBD while the control group got only vehicle. The outcome measures were rate of wound closure, wound cells expressing IL-33 and CTGF, and ILC profiles. In B6, the initial rate of wound closure was slower but there was no delay in the time to final closure, and cells expressing IL-33 was significantly reduced. CTGF + cells were higher in db/bd wounds treated with CBD. These data support the potential use of CBD to improve diabetic cutaneous wound healing.

Potential of CBD Acting on Cannabinoid Receptors CB1 and CB2 in Ischemic Stroke

Stroke is one of the leading causes of death. It not only affects adult people but also many children. It is estimated that, every year, 15 million people suffer a stroke worldwide. Among them, 5 million people die, while 5 million people are left permanently disabled. In this sense, the research to find new treatments should be accompanied with new therapies to combat neuronal death and to avoid developing cognitive impairment and dementia. Phytocannabinoids are among the compounds that have been used by mankind for the longest period of history. Their beneficial effects such as pain regulation or neuroprotection are widely known and make them possible therapeutic agents with high potential. These compounds bind cannabinoid receptors CB1 and CB2. Unfortunately, the psychoactive side effect has displaced them in the vast majority of areas. Thus, progress in the research and development of new compounds that show efficiency as neuroprotectors without this psychoactive effect is essential. On the one hand, these compounds could selectively bind the CB2 receptor that does not show psychoactive effects and, in glia, has opened new avenues in this field of research, shedding new light on the use of cannabinoid receptors as therapeutic targets to combat neurodegenerative diseases such as Alzheimer's, Parkinson's disease, or stroke. On the other hand, a new possibility lies in the formation of heteromers containing cannabinoid receptors. Heteromers are new functional units that show new properties compared to the individual protomers. Thus, they represent a new possibility that may offer the beneficial effects of cannabinoids devoid of the unwanted psychoactive effect. Nowadays, the approval of a mixture of CBD (cannabidiol) and Δ9-THC (tetrahydrocannabinol) to treat the neuropathic pain and spasticity in multiple sclerosis or purified cannabidiol to combat pediatric epilepsy have opened new therapeutic possibilities in the field of cannabinoids and returned these compounds to the front line of research to treat pathologies as relevant as stroke.

In Vitro and In Vivo Anti-Inflammatory and Antidepressant-like Effects of Cannabis sativa L. Extracts

Cannabis sativa L. has been widely used by humans for centuries for various purposes, such as industrial, ceremonial, medicinal, and food. The bioactive components of Cannabis sativa L. can be classified into two main groups: cannabinoids and terpenes. These bioactive components of Cannabis sativa L. leaf and inflorescence extracts were analyzed. Mice were systemically administered 30 mg/kg of Cannabis sativa L. leaf extract 1 h before lipopolysaccharide (LPS) administration, and behavioral tests were performed. We conducted an investigation into the oxygen saturation, oxygen tension, and degranulation of mast cells (MCs) in the deep cervical lymph nodes (DCLNs). To evaluate the anti-inflammatory effect of Cannabis sativa L. extracts in BV2 microglial cells, we assessed nitrite production and the expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. The main bioactive components of the Cannabis sativa L. extracts were THCA (a cannabinoid) and β-caryophyllene (a terpene). Cannabis sativa L. leaf extract reduced the immobility time in the forced swimming test and increased sucrose preference in the LPS model, without affecting the total distance and time in the center in the open field test. Additionally, Cannabis sativa L. leaf extract improved oxygen levels and inhibited the degranulation of MCs in DCLNs. The Cannabis sativa L. extracts inhibited IL-1β, IL-6, TNF-α, nitrite, iNOS, and COX-2 expression in BV2 microglia cells. The efficacy of Cannabis sativa L. extracts was suggested to be due to the entourage effect of various bioactive phytochemicals. Our findings indicate that these extracts have the potential to be used as effective treatments for a variety of diseases associated with acute inflammatory responses.

Cannabinoid Analgesia in Postoperative Pain Management: From Molecular Mechanisms to Clinical Reality

Postoperative pain (POP) is a challenging clinical phenomenon that affects the majority of surgical patients and demands effective management to mitigate adverse outcomes such as persistent pain. The primary goal of POP management is to alleviate suffering and facilitate a seamless return to normal function for the patient. Despite compelling evidence of its drawbacks, opioid analgesia remains the basis of POP treatment. Novel therapeutic approaches rely on multimodal analgesia, integrating different pharmacological strategies to optimize efficacy while minimizing adverse effects. The recognition of the imperative role of the endocannabinoid system in pain regulation has prompted the investigation of cannabinoid compounds as a new therapeutic avenue. Cannabinoids may serve as adjuvants, enhancing the analgesic effects of other drugs and potentially replacing or at least reducing the dependence on other long-term analgesics in pain management. This narrative review succinctly summarizes pertinent information on the molecular mechanisms, clinical therapeutic benefits, and considerations associated with the plausible use of various cannabinoid compounds in treating POP. According to the available evidence, cannabinoid compounds modulate specific molecular mechanisms intimately involved in POP. However, only two of the eleven clinical trials that evaluated the efficacy of different cannabinoid interventions showed positive results.

The Influence of Cannabinoids on Drosophila Behaviors, Longevity, and Traumatic Injury Responses of the Adult Nervous System

Introduction: The legalization of cannabis products has increased their usage in the United States. Among the ∼500 active compounds, this is especially true for cannabidiol (CBD)-based products, which are being used to treat a range of ailments. Research is ongoing regarding the safety, therapeutic potential, and molecular mechanism of cannabinoids. Drosophila (fruit flies) are widely used to model a range of factors that impact neural aging, stress responses, and longevity. Materials and Methods: Adult wild-type Drosophila melanogaster cohorts (w1118/+) were treated with different Δ9-tetrahydrocannabinol (THC) and CBD dosages and examined for neural protective properties using established neural aging and trauma models. The therapeutic potential of each compound was assessed using circadian and locomotor behavioral assays and longevity profiles. Changes to NF-κB pathway activation were assessed by measuring expression levels of downstream targets using quantitative real-time polymerase chain reaction analysis of neural cDNAs. Results: Flies exposed to different CBD or THC dosages showed minimal effects to sleep and circadian-based behaviors or the age-dependent decline in locomotion. The 2-week CBD (3 μM) treatment did significantly enhance longevity. Flies exposed to different CBD and THC dosages were also examined under stress conditions, using the Drosophila mild traumatic brain injury (mTBI) model (10×). Pretreatment with either compound did not alter baseline expression of key inflammatory markers (NF-κB targets), but did reduce neural mRNA profiles at a key 4-h time point following mTBI exposure. Locomotor responses were also significantly improved 1 and 2 weeks following mTBI. After mTBI (10×) exposure, the 48-h mortality rate improved for CBD (3 μM)-treated flies, as were global average longevity profiles for other CBD doses tested. While not significant, THC (0.1 μM)-treated flies show a net positive impact on acute mortality and longevity profiles following mTBI (10×) exposure. Conclusions: This study shows that the CBD and THC dosages examined had at most a modest impact on basal neural function, while demonstrating that CBD treatments had significant neural protective properties for flies following exposure to traumatic injury.

The Impact of Cannabis Use on Cognition in People with HIV: Evidence of Function-Dependent Effects and Mechanisms from Clinical and Preclinical Studies

PURPOSE OF REVIEW

Cannabis may have beneficial anti-inflammatory effects in people with HIV (PWH); however, given this population's high burden of persisting neurocognitive impairment (NCI), clinicians are concerned they may be particularly vulnerable to the deleterious effects of cannabis on cognition. Here, we present a systematic scoping review of clinical and preclinical studies evaluating the effects of cannabinoid exposure on cognition in HIV.

RECENT FINDINGS

Results revealed little evidence to support a harmful impact of cannabis use on cognition in HIV, with few eligible preclinical data existing. Furthermore, the beneficial/harmful effects of cannabis use observed on cognition were function-dependent and confounded by several factors (e.g., age, frequency of use). Results are discussed alongside potential mechanisms of cannabis effects on cognition in HIV (e.g., anti-inflammatory), and considerations are outlined for screening PWH that may benefit from cannabis interventions. We further highlight the value of accelerating research discoveries in this area by utilizing translatable cross-species tasks to facilitate comparisons across human and animal work.

Modulation of Oxidative Stress and Neuroinflammation by Cannabidiol (CBD): Promising Targets for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease and the most common form of dementia globally. Although the direct cause of AD remains under debate, neuroinflammation and oxidative stress are critical components in its pathogenesis and progression. As a result, compounds like cannabidiol (CBD) are being increasingly investigated for their ability to provide antioxidant and anti-inflammatory neuroprotection. CBD is the primary non-psychotropic phytocannabinoid derived from Cannabis sativa. It has been found to provide beneficial outcomes in a variety of medical conditions and is gaining increasing attention for its potential therapeutic application in AD. CBD is not psychoactive and its lipophilic nature allows its rapid distribution throughout the body, including across the blood-brain barrier (BBB). CBD also possesses anti-inflammatory, antioxidant, and neuroprotective properties, making it a viable candidate for AD treatment. This review outlines CBD's mechanism of action, the role of oxidative stress and neuroinflammation in AD, and the effectiveness and limitations of CBD in preclinical models of AD.

Single-Nucleus Transcriptome Profiling from the Hippocampus of a PTSD Mouse Model and CBD-Treated Cohorts

Post-traumatic stress disorder (PTSD) is the most common psychiatric disorder after a catastrophic event; however, the efficacious treatment options remain insufficient. Increasing evidence suggests that cannabidiol (CBD) exhibits optimal therapeutic effects for treating PTSD. To elucidate the cell-type-specific transcriptomic pathology of PTSD and the mechanisms of CBD against this disease, we conducted single-nucleus RNA sequencing (snRNA-seq) in the hippocampus of PTSD-modeled mice and CBD-treated cohorts. We constructed a mouse model by adding electric foot shocks following exposure to single prolonged stress (SPS+S) and tested the freezing time, anxiety-like behavior, and cognitive behavior. CBD was administrated before every behavioral test. The PTSD-modeled mice displayed behaviors resembling those of PTSD in all behavioral tests, and CBD treatment alleviated all of these PTSD-like behaviors (n = 8/group). Three mice with representative behavioral phenotypes were selected from each group for snRNA-seq 15 days after the SPS+S. We primarily focused on the excitatory neurons (ExNs) and inhibitory neurons (InNs), which accounted for 68.4% of the total cell annotations. A total of 88 differentially upregulated genes and 305 differentially downregulated genes were found in the PTSD mice, which were found to exhibit significant alterations in pathways and biological processes associated with fear response, synaptic communication, protein synthesis, oxidative phosphorylation, and oxidative stress response. A total of 63 overlapping genes in InNs were identified as key genes for CBD in the treatment of PTSD. Subsequent Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the anti-PTSD effect of CBD was related to the regulation of protein synthesis, oxidative phosphorylation, oxidative stress response, and fear response. Furthermore, gene set enrichment analysis (GSEA) revealed that CBD also enhanced retrograde endocannabinoid signaling in ExNs, which was found to be suppressed in the PTSD group. Our research may provide a potential explanation for the pathogenesis of PTSD and facilitate the discovery of novel therapeutic targets for drug development. Moreover, it may shed light on the therapeutic mechanisms of CBD.

Cannabinoid treatments in epilepsy and seizure disorders

Cannabis has been used to treat convulsions and other disorders since ancient times. In the last few decades, preclinical animal studies and clinical investigations have established the role of cannabidiol (CBD) in treating epilepsy and seizures and support potential therapeutic benefits for cannabinoids in other neurological and psychiatric disorders. Here, we comprehensively review the role of cannabinoids in epilepsy. We briefly review the diverse physiological processes mediating the central nervous system response to cannabinoids, including Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol, and terpenes. Next, we characterize the anti- and proconvulsive effects of cannabinoids from animal studies of acute seizures and chronic epileptogenesis. We then review the clinical literature on using cannabinoids to treat epilepsy, including anecdotal evidence and case studies as well as the more recent randomized controlled clinical trials that led to US Food and Drug Administration approval of CBD for some types of epilepsy. Overall, we seek to evaluate our current understanding of cannabinoids in epilepsy and focus future research on unanswered questions.