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.

Metabolic models predict fotemustine and the combination of eflornithine/rifamycin and adapalene/cannabidiol for the treatment of gliomas.

Gliomas are the most common type of malignant brain tumors, with glioblastoma multiforme (GBM) having a median survival of 15 months due to drug resistance and relapse. The treatment of gliomas relies on surgery, radiotherapy and chemotherapy. Only 12 anti-brain tumor chemotherapies (AntiBCs), mostly alkylating agents, have been approved so far. Glioma subtype-specific metabolic models were reconstructed to simulate metabolite exchanges, in silico knockouts and the prediction of drug and drug combinations for all three subtypes. The simulations were confronted with literature, high-throughput screenings (HTSs), xenograft and clinical trial data to validate the workflow and further prioritize the drug candidates. The three subtype models accurately displayed different degrees of dependencies toward glutamine and glutamate. Furthermore, 33 single drugs, mainly antimetabolites and TXNRD1-inhibitors, as well as 17 drug combinations were predicted as potential candidates for gliomas. Half of these drug candidates have been previously tested in HTSs. Half of the tested drug candidates reduce proliferation in cell lines and two-thirds in xenografts. Most combinations were predicted to be efficient for all three glioma types. However, eflornithine/rifamycin and cannabidiol/adapalene were predicted specifically for GBM and low-grade glioma, respectively. Most drug candidates had comparable efficiency in preclinical tests, cerebrospinal fluid bioavailability and mode-of-action to AntiBCs. However, fotemustine and valganciclovir alone and eflornithine and celecoxib in combination with AntiBCs improved the survival compared to AntiBCs in two-arms, phase I/II and higher glioma clinical trials. Our work highlights the potential of metabolic modeling in advancing glioma drug discovery, which accurately predicted metabolic vulnerabilities, repurposable drugs and combinations for the glioma subtypes.

Dual-pocket inhibition of Nav channels by the antiepileptic drug lamotrigine.

Voltage-gated sodium (Nav) channels govern membrane excitability, thus setting the foundation for various physiological and neuronal processes. Nav channels serve as the primary targets for several classes of widely used and investigational drugs, including local anesthetics, antiepileptic drugs, antiarrhythmics, and analgesics. In this study, we present cryogenic electron microscopy (cryo-EM) structures of human Nav1.7 bound to two clinical drugs, riluzole (RLZ) and lamotrigine (LTG), at resolutions of 2.9 Å and 2.7 Å, respectively. A 3D EM reconstruction of ligand-free Nav1.7 was also obtained at 2.1 Å resolution. RLZ resides in the central cavity of the pore domain and is coordinated by residues from repeats III and IV. Whereas one LTG molecule also binds to the central cavity, the other is found beneath the intracellular gate, known as site BIG. Therefore, LTG, similar to lacosamide and cannabidiol, blocks Nav channels via a dual-pocket mechanism. These structures, complemented with docking and mutational analyses, also explain the structure-activity relationships of the LTG-related linear 6,6 series that have been developed for improved efficacy and subtype specificity on different Nav channels. Our findings reveal the molecular basis for these drugs' mechanism of action and will aid the development of novel antiepileptic and pain-relieving drugs.

Goods and Bads of the Endocannabinoid System as a Therapeutic Target: Lessons Learned after 30 Years.

The cannabis derivative marijuana is the most widely used recreational drug in the Western world and is consumed by an estimated 83 million individuals (∼3% of the world population). In recent years, there has been a marked transformation in society regarding the risk perception of cannabis, driven by its legalization and medical use in many states in the United States and worldwide. Compelling research evidence and the Food and Drug Administration cannabis-derived cannabidiol approval for severe childhood epilepsy have confirmed the large therapeutic potential of cannabidiol itself, Δ9-tetrahydrocannabinol and other plant-derived cannabinoids (phytocannabinoids). Of note, our body has a complex endocannabinoid system (ECS)-made of receptors, metabolic enzymes, and transporters-that is also regulated by phytocannabinoids. The first endocannabinoid to be discovered 30 years ago was anandamide (N-arachidonoyl-ethanolamine); since then, distinct elements of the ECS have been the target of drug design programs aimed at curing (or at least slowing down) a number of human diseases, both in the central nervous system and at the periphery. Here a critical review of our knowledge of the goods and bads of the ECS as a therapeutic target is presented to define the benefits of ECS-active phytocannabinoids and ECS-oriented synthetic drugs for human health. SIGNIFICANCE STATEMENT: The endocannabinoid system plays important roles virtually everywhere in our body and is either involved in mediating key processes of central and peripheral diseases or represents a therapeutic target for treatment. Therefore, understanding the structure, function, and pharmacology of the components of this complex system, and in particular of key receptors (like cannabinoid receptors 1 and 2) and metabolic enzymes (like fatty acid amide hydrolase and monoacylglycerol lipase), will advance our understanding of endocannabinoid signaling and activity at molecular, cellular, and system levels, providing new opportunities to treat patients.

Cannabidiol protects against acute aortic dissection by inhibiting macrophage infiltration and PMAIP1-induced vascular smooth muscle cell apoptosis.

Acute aortic dissection (AAD) progresses rapidly and is associated with high mortality; therefore, there remains an urgent need for pharmacological agents that can protect against AAD. Herein, we examined the therapeutic effects of cannabidiol (CBD) in AAD by establishing a suitable mouse model. In addition, we performed human AAD single-cell RNA sequencing and mouse AAD bulk RNA sequencing to elucidate the potential underlying mechanism of CBD. Pathological assays and in vitro studies were performed to verify the results of the bioinformatic analysis and explore the pharmacological function of CBD. In a ß-aminopropionitrile (BAPN)-induced AAD mouse model, CBD reduced AAD-associated morbidity and mortality, alleviated abnormal enlargement of the ascending aorta and aortic arch, and suppressed macrophage infiltration and vascular smooth muscle cell (VSMC) apoptosis. Bioinformatic analysis revealed that the pro-apoptotic gene PMAIP1 was highly expressed in human and mouse AAD samples, and CBD could inhibit Pmaip1 expression in AAD mice. Using human aortic VSMCs (HAVSMCs) co-cultured with M1 macrophages, we revealed that CBD alleviated HAVSMCs mitochondrial-dependent apoptosis by suppressing the BAPN-induced overexpression of PMAIP1 in M1 macrophages. PMAIP1 potentially mediates HAVSMCs apoptosis by regulating Bax and Bcl2 expression. Accordingly, CBD reduced AAD-associated morbidity and mortality and mitigated the progression of AAD in a mouse model. The CBD-induced effects were potentially mediated by suppressing macrophage infiltration and PMAIP1 (primarily expressed in macrophages)-induced VSMC apoptosis. Our findings offer novel insights into M1 macrophages and HAVSMCs interaction during AAD progression, highlighting the potential of CBD as a therapeutic candidate for AAD treatment.

Cannabidiol protects C2C12 myotubes against cisplatin-induced atrophy by regulating oxidative stress.

Cancer and chemotherapy induce a severe loss of muscle mass (known as cachexia), which negatively impact cancer treatment and patient survival. The aim of the present study was to investigate whether cannabidiol (CBD) administration may potentially antagonize the effects of cisplatin in inducing muscle atrophy, using a model of myotubes in culture. Cisplatin treatment resulted in a reduction of myotube diameter (15.7 ± 0.3 vs. 22.2 ± 0.5 µm, P < 0.01) that was restored to control level with 5 µM CBD (20.1 ± 0.4 µM, P < 0.01). Protein homeostasis was severely altered with a ≈70% reduction in protein synthesis (P < 0.01) and a twofold increase in proteolysis (P < 0.05) in response to cisplatin. Both parameters were dose dependently restored by CBD cotreatment. Cisplatin treatment was associated with increased thiobarbituric acid reactive substances (TBARS) content (0.21 ± 0.03 to 0.48 ± 0.03 nmol/mg prot, P < 0.05), catalase activity (0.24 ± 0.01 vs. 0.13 ± 0.02 nmol/min/µg prot, P < 0.01), whereas CBD cotreatment normalized TBARS content to control values (0.22 ± 0.01 nmol/mg prot, P < 0.01) and reduced catalase activity (0.17 ± 0.01 nmol/min/µg prot, P < 0.05). These changes were associated with increased mRNA expression of GPX1, SOD1, SOD2, and CAT mRNA expression in response to cisplatin (P < 0.01), which was corrected by CBD cotreatment (P < 0.05). Finally, cisplatin treatment increased the mitochondrial protein content of NDUFB8, UQCRC2, COX4, and VDAC1 (involved in mitochondrial respiration and apoptosis), and CBD cotreatment restored their expression to control values. Altogether, our results demonstrated that CBD antagonize the cisplatin-induced C2C12 myotube atrophy and could be used as an adjuvant in the treatment of cancer cachexia to help maintain muscle mass and improve patient quality of life.NEW & NOTEWORTHY In an in vitro model, cisplatin treatment led to myotube atrophy associated with dysregulation of protein homeostasis and increased oxidative stress, resulting in increased apoptosis. Cotreatment with cannabidiol was able to prevent this phenotype by promoting protein homeostasis and reducing oxidative stress.

Antiviral effect of cannabidiol on K18-hACE2 transgenic mice infected with SARS-CoV-2.

The aim of this study was to determine the antiviral activity of cannabidiol (CBD) against SARS-CoV-2 infection. CBD is the second most studied cannabinoid obtained from Cannabis plants. We investigated the potential use of CBD, which has so far proven to have a positive effect on different diseases, in the SARS-CoV-2 infection. To test this, in vivo studies were carried out using K18-hACE2 transgenic mice. To reveal the potential therapeutic effect of the CBD at the histopathological and molecular level challenge experiments were performed. The study was designed with two groups (n = 10) and in the treatment group animals were infected with SARS-CoV-2 virus strain B.1.1.7 alpha before the administration of CBD. While the disease progressed and resulted in death in the control group that was infected by the virus alone, it was observed that the infection slowed down and the survival rate increased in the mice treated with CBD along with the virus. In this study, K18-hACE2 transgenic mice infected with the wild SARS-CoV-2 virus were used to investigate and prove the antiviral activity of CBD.

A protocol for rapid generation cycling (speed breeding) of hemp (Cannabis sativa) for research and agriculture.

Hemp (Cannabis sativa) is a highly versatile crop with a multitude of applications, from textiles, biofuel and building material to high-value food products for consumer markets. Furthermore, non-hallucinogenic cannabinoids like cannabidiol (CBD), which can be extracted from female hemp flowers, are potentially valuable pharmacological compounds. In addition, hemp has high carbon sequestration potential associated with its rapid growth rate. Therefore, the hemp industry is gaining more traction and breeding hemp cultivars adapted to local climate conditions or bred for specific applications is becoming increasingly important. Here, we present a method for the rapid generation cycling (speed breeding) of hemp. The speed breeding protocol makes use of the photoperiod sensitivity of Cannabis. It encompasses vegetative growth of the plants for 2 weeks under continuous light, followed by 4 weeks under short-day conditions, during which flower induction, pollination and seed development proceed, and finally a seed ripening phase under continuous light and water stress. With the protocol described here, a generation time of under 9 weeks (61 days) from seed to seed can be achieved. Furthermore, our method synchronises the flowering time of different hemp cultivars, thus facilitating crosses between cultivars. The extremely short generation time will enable hemp researchers and breeders to perform crosses in a time-efficient way and generate new hemp cultivars with defined genetic characteristics over a short period of time.

The two synthetic cannabinoid compounds 4'-F-CBD and HU-910 efficiently restrain inflammatory responses of brain microglia and astrocytes.

To study the anti-inflammatory potential of the two synthetic cannabinoids 4'-F-CBD and HU-910, we used post-natal brain cultures of mouse microglial cells and astrocytes activated by reference inflammogens. We found that 4'-F-CBD and HU-910 efficiently curtailed the release of TNF-α, IL-6, and IL-1ß in microglia and astrocytes activated by the bacterial Toll-Like Receptor (TLR)4 ligand LPS. Upon LPS challenge, 4'-F-CBD and HU-910 also prevented the activation of phenotypic activation markers specific to microglia and astrocytes, that is, Iba-1 and GFAP, respectively. In microglial cells, the two test compounds also efficiently restrained LPS-stimulated release of glutamate, a non-cytokine inflammation marker for these cells. The immunosuppressive effects of the two cannabinoid compounds were concentration-dependent and observable between 1 and 10 µM. These effects were not dependent on cannabinoid or cannabinoid-like receptors. Both 4'-F-CBD and HU-910 were also capable of restraining the inflammogenic activity of Pam3CSK4, a lipopeptide that activates TLR2, and of BzATP, a prototypic agonist of P2X7 purinergic receptors, suggesting that these two cannabinoids could exert immunosuppressive effects against a variety of inflammatory stimuli. Using LPS-stimulated microglia and astrocytes, we established that the immunosuppressive action of 4'-F-CBD and HU-910 resulted from the inhibition of ROS produced by NADPH oxidase and subsequent repression of NF-κB-dependent signaling events. Our results suggest that 4'-F-CBD and HU-910 may have therapeutic utility in pathological conditions where neuroinflammatory processes are prominent.

Cannabidiol activates MAPK pathway to induce apoptosis, paraptosis, and autophagy in colorectal cancer cells.

Mitogen-activated protein kinase (MAPK) activation by natural compounds is known to be involved in the induction of apoptosis, paraptosis, and autophagy. Cannabidiol (CBD), a bioactive compound found in Cannabis sativa, is endowed with many pharmacological activities. We investigated the cytotoxic effect of CBD in a panel of colorectal cancer (CRC) cells (HT-29, SW480, HCT-116, and HCT-15). CBD induced significant cytotoxicity as evidenced by the results of MTT  assay, live-dead assay, and flow cytometric analysis. Since CBD displayed cytotoxicity against CRC cells, we examined the effect of CBD on apoptosis, paraptosis, and autophagy. CBD decreased the expression of antiapoptotic proteins and increased the Annexin-V-positive as well as TUNEL-positive cells suggesting that CBD induces apoptosis. CBD increased the expression of ATF4 (activating transcription factor 4) and CHOP (CCAAT/enhancer-binding protein homologous protein), elevated endoplasmic reticulum stress, and enhanced reactive oxygen species levels indicating that CBD also promotes paraptosis. CBD also induced the expression of Atg7, phospho-Beclin-1, and LC3 suggesting that CBD also accelerates autophagy. Since, the MAPK pathway is a common cascade that is involved in the regulation of apoptosis, paraptosis, and autophagy, we investigated the effect of CBD on the activation of JNK, p38, and ERK pathways. CBD activated all the forms of MAPK proteins and pharmacological inhibition of these proteins reverted the observed effects. Our findings implied that CBD could induce CRC cell death by activating apoptosis, paraptosis, and autophagy through the activation of the MAPK pathway.

Prenatal tetrahydrocannabinol and cannabidiol exposure produce sex-specific pathophysiological phenotypes in the adolescent prefrontal cortex and hippocampus.

Clinical and preclinical evidence has demonstrated an increased risk for neuropsychiatric disorders following prenatal cannabinoid exposure. However, given the phytochemical complexity of cannabis, there is a need to understand how specific components of cannabis may contribute to these neurodevelopmental risks later in life. To investigate this, a rat model of prenatal cannabinoid exposure was utilized to examine the impacts of specific cannabis constituents (Δ9-tetrahydrocannabinol [THC]; cannabidiol [CBD]) alone and in combination on future neuropsychiatric liability in male and female offspring. Prenatal THC and CBD exposure were associated with low birth weight. At adolescence, offspring displayed sex-specific behavioural changes in anxiety, temporal order and social cognition, and sensorimotor gating. These phenotypes were associated with sex and treatment-specific neuronal and gene transcriptional alterations in the prefrontal cortex, and ventral hippocampus, regions where the endocannabinoid system is implicated in affective and cognitive development. Electrophysiology and RT-qPCR analysis in these regions implicated dysregulation of the endocannabinoid system and balance of excitatory and inhibitory signalling in the developmental consequences of prenatal cannabinoids. These findings reveal critical insights into how specific cannabinoids can differentially impact the developing fetal brains of males and females to enhance subsequent neuropsychiatric risk.

Cannabidiol attenuates seizure susceptibility and behavioural deficits in adult CDKL5R59X knock-in mice.

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is caused by a loss-of-function mutation in CDKL5 gene, encoding a serine-threonine kinase highly expressed in the brain. CDD manifests with early-onset epilepsy, autism, motor impairment and severe intellectual disability. While there are no known treatments for CDD, the use of cannabidiol has recently been introduced into clinical practice for neurodevelopmental disorders. Given the increased clinical utilization of cannabidiol, we examined its efficacy in the CDKL5R59X knock-in (R59X) mice, a CDD model based on a human mutation that exhibits both lifelong seizure susceptibility and behavioural deficits. We found that cannabidiol pre-treatment rescued the increased seizure susceptibility in response to the chemoconvulsant pentylenetetrazol (PTZ), attenuated working memory and long-term memory impairments, and rescued social deficits in adult R59X mice. To elucidate a potential mechanism, we compared the developmental hippocampal and cortical expression of common endocannabinoid (eCB) targets in R59X mice and their wild-type littermates, including cannabinoid type 1 receptor (CB1R), transient receptor potential vanilloid type 1 (TRPV1) and 2 (TRPV2), G-coupled protein receptor 55 (GPR55) and adenosine receptor 1 (A1R). Many of these eCB targets were developmentally regulated in both R59X and wild-type mice. In addition, adult R59X mice demonstrated significantly decreased expression of CB1R and TRPV1 in the hippocampus, and TRPV2 in the cortex, while TRPV1 was increased in the cortex. These findings support the potential for dysregulation of eCB signalling as a plausible mechanism and therapeutic target in CDD, given the efficacy of cannabidiol to attenuate hyperexcitability and behavioural deficits in this disorder.

Beyond the CB1 Receptor: Is Cannabidiol the Answer for Disorders of Motivation?

The Cannabis sativa plant has been used to treat various physiological and psychiatric conditions for millennia. Current research is focused on isolating potentially therapeutic chemical constituents from the plant for use in the treatment of many central nervous system disorders. Of particular interest is the primary nonpsychoactive constituent cannabidiol (CBD). Unlike Δ(9)-tetrahydrocannabinol (THC), CBD does not act through the cannabinoid type 1 (CB1) receptor but has many other receptor targets that may play a role in psychiatric disorders. Here we review preclinical and clinical data outlining the therapeutic efficacy of CBD for the treatment of motivational disorders such as drug addiction, anxiety, and depression. Across studies, findings suggest promising treatment effects and potentially overlapping mechanisms of action for CBD in these disorders and indicate the need for further systematic investigation of the viability of CBD as a psychiatric pharmacotherapy.

Enhanced brain-targeting and efficacy of cannabidiol via RVG-Exo/CBD nanodelivery system.

This study introduces an innovative brain-targeted drug delivery system, RVG-Exo/CBD, utilizing rabies virus glycoprotein (RVG)-engineered exosomes for encapsulating cannabidiol (CBD). The novel delivery system was meticulously characterized, confirming the maintenance of exosomal integrity, size, and successful drug encapsulation with a high drug loading rate of 83.0 %. Evaluation of the RVG-Exo/CBD's brain-targeting capability demonstrated superior distribution and retention in brain tissue compared to unmodified exosomes, primarily validated through in vivo fluorescence imaging. The efficacy of this delivery system was assessed using a behavioral sensitization model in mice, where RVG-Exo/CBD notably suppressed methamphetamine-induced hyperactivity more effectively than CBD alone, indicating a reduction in effective dose and enhanced bioavailability. Overall, the RVG-Exo/CBD system emerges as a promising strategy for enhancing the therapeutic efficacy and safety of CBD, particularly for neurological applications, highlighting its potential for addressing the limitations associated with traditional CBD administration in clinical settings.

Effects of cannabidiol and Δ9-tetrahydrocannabinol on cytochrome P450 enzymes: a systematic review.

Due to legal, political, and cultural changes, the use of cannabis has rapidly increased in recent years. Research has demonstrated that the cannabinoids cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) inhibit and induce cytochrome P450 (CYP450) enzymes. The objective of this review is to evaluate the effect of CBD and THC on the activity of CYP450 enzymes and the implications for drug-drug interactions (DDIs) with psychotropic agents that are CYP substrates. A systematic search was conducted using PubMed, Scopus, Scientific Electronic Library Online (SciELO) and PsychINFO. Search terms included 'cannabidiol', 'tetrahydrocannabinol', and 'cytochrome P450'. A total of seven studies evaluating the interaction of THC and CBD with CYP450 enzymes and psychotropic drugs were included. Both preclinical and clinical studies were included. Results from the included studies indicate that both CBD and THC inhibit several CYP450 enzymes including, but not limited to, CYP1A2, CYP3C19, and CYP2B6. While there are a few known CYP450 enzymes that are induced by THC and CBD, the induction of CYP450 enzymes is an understudied area of research and lacks clinical data. The inhibitory effects observed by CBD and THC on CYP450 enzymes vary in magnitude and may decrease the metabolism of psychotropic agents, cause changes in plasma levels of psychotropic medications, and increase adverse effects. Our findings clearly present interactions between THC and CBD and several CYP450 enzymes, providing clinicians evidence of a high risk of DDIs for patients who consume both cannabis and psychotropic medication. However, more clinical research is necessary before results are applied to clinical settings.

Tyrosine phosphorylation and palmitoylation of TRPV2 ion channel tune microglial beta-amyloid peptide phagocytosis.

Alzheimer's disease (AD) is the leading form of dementia, characterized by the accumulation and aggregation of amyloid in brain. Transient receptor potential vanilloid 2 (TRPV2) is an ion channel involved in diverse physiopathological processes, including microglial phagocytosis. Previous studies suggested that cannabidiol (CBD), an activator of TRPV2, improves microglial amyloid-ß (Aß) phagocytosis by TRPV2 modulation. However, the molecular mechanism of TRPV2 in microglial Aß phagocytosis remains unknown. In this study, we aimed to investigate the involvement of TRPV2 channel in microglial Aß phagocytosis and the underlying mechanisms. Utilizing human datasets, mouse primary neuron and microglia cultures, and AD model mice, to evaluate TRPV2 expression and microglial Aß phagocytosis in both in vivo and in vitro. TRPV2 was expressed in cortex, hippocampus, and microglia.Cannabidiol (CBD) could activate and sensitize TRPV2 channel. Short-term CBD (1 week) injection intraperitoneally (i.p.) reduced the expression of neuroinflammation and microglial phagocytic receptors, but long-term CBD (3 week) administration (i.p.) induced neuroinflammation and suppressed the expression of microglial phagocytic receptors in APP/PS1 mice. Furthermore, the hyper-sensitivity of TRPV2 channel was mediated by tyrosine phosphorylation at the molecular sites Tyr(338), Tyr(466), and Tyr(520) by protein tyrosine kinase JAK1, and these sites mutation reduced the microglial Aß phagocytosis partially dependence on its localization. While TRPV2 was palmitoylated at Cys 277 site and blocking TRPV2 palmitoylation improved microglial Aß phagocytosis. Moreover, it was demonstrated that TRPV2 palmitoylation was dynamically regulated by ZDHHC21. Overall, our findings elucidated the intricate interplay between TRPV2 channel regulated by tyrosine phosphorylation/dephosphorylation and cysteine palmitoylation/depalmitoylation, which had divergent effects on microglial Aß phagocytosis. These findings provide valuable insights into the underlying mechanisms linking microglial phagocytosis and TRPV2 sensitivity, and offer potential therapeutic strategies for managing AD.

Impact of cannabidiol on brain glucose metabolism of C57Bl/6 male mice previously exposed to cocaine.

Despite evidence of the beneficial effects of cannabidiol (CBD) in animal models of cocaine use disorder (CUD), CBD neuronal mechanisms remain poorly understood. This study investigated the effects of CBD treatment on brain glucose metabolism, in a CUD animal model, using [18F]FDG positron emission tomography (PET). Male C57Bl/6 mice were injected with cocaine (20 mg/kg, i.p.) every other day for 9 days, followed by 8 days of CBD administration (30 mg/kg, i.p.). After 48 h, animals were challenged with cocaine. Control animals received saline/vehicle. [18F]FDG PET was performed at four time points: baseline, last day of sensitization, last day of withdrawal/CBD treatment, and challenge. Subsequently, the animals were euthanized and immunohistochemistry was performed on the hippocampus and amygdala to assess the CB1 receptors, neuronal nuclear protein, microglia (Iba1), and astrocytes (GFAP). Results showed that cocaine administration increased [18F]FDG uptake following sensitization. CBD treatment also increased [18F]FDG uptake in both saline and cocaine groups. However, animals that were sensitized and challenged with cocaine, and those receiving only an acute cocaine injection during the challenge phase, did not exhibit increased [18F]FDG uptake when treated with CBD. Furthermore, CBD induced modifications in the integrated density of NeuN, Iba, GFAP, and CB1R in the hippocampus and amygdala. This is the first study addressing the impact of CBD on brain glucose metabolism in a preclinical model of CUD using PET. Our findings suggest that CBD disrupts cocaine-induced changes in brain energy consumption and activity, which might be correlated with alterations in neuronal and glial function.

Cannabidiol Modulation of Nicotine-Induced Toxicity: Assessing Effects on Behavior, Brain-Derived Neurotrophic Factor, and Oxidative Stress in C57BL/6 Male Mice.

High doses of nicotine administered to rodents serve as a model for studying anxiety and test compounds' potential anxiolytic effects. At these doses, anxiety in rodents is accompanied by disruption of brain-derived neurotrophic factor (BDNF). The endocannabinoids and nicotine modulate several central nervous system processes via their specific receptors, impacting locomotion, anxiety, memory, nociception, and reward. Cannabidiol (CBD), an active ingredient of Cannabis sativa L., is devoid of psychoactive actions and has gained attention for its anxiolytic, antioxidant, and anti-inflammatory properties, among others. This work aims to examine the potential anxiety-reducing properties of CBD in a well-established experimental mouse model of anxiety-like behavior induced by high doses of nicotine on male C57BL/6 mice. In this context, the open-field behavioral test was specially conducted to assess CBD's effects on anxiety-like behavior and locomotion. Brain neuronal plasticity, modulated by BDNF, along with a diverse array of blood's metabolic markers, was examined as a means of evaluating systemic toxicity under various treatments. Finally, oxidative stress was evaluated through the measurement of glutathione (GSH), superoxide dismutase (SOD), and malondialdehyde (MDA), while pro-inflammatory cytokine assessments were conducted to evaluate redox status and immune system function. Our research suggests that CBD shows potential in reducing anxiety-like behaviors induced by high doses of nicotine, by mitigating changes in BDNF protein levels in cerebral hemispheres and cerebellum. At the same time, CBD targets specific liver enzymes, maintains tissue's systemic toxicity (i.e., renal, kidney, and pancreatic), balances redox status (SOD, GSH, and MDA), and regulates the secretion of pro-inflammatory cytokines (TNF-alpha and IL-6).

Assessing Dose- and Sex-Dependent Antinociceptive Effects of Cannabidiol and Amitriptyline, Alone and in Combination, and Exploring Mechanism of Action Involving Serotonin 1A Receptors.

Inflammatory pain is caused by tissue hypersensitization and is a component of rheumatic diseases, frequently causing chronic pain. Current guidelines use a multimodal approach to pain and sociocultural changes have renewed interest in cannabinoid use, particularly cannabidiol (CBD), for pain. The tricyclic antidepressant amitriptyline (AT) is approved for use in pain-related syndromes, alone and within a multimodal approach. Therefore, we investigated sex- and dose-dependent effects of CBD and AT antinociception in the 2.5% formalin inflammatory pain model. Male and female C57BL/6J mice were pretreated with either vehicle, CBD (0.3-100 mg/kg), or AT (0.1-30 mg/kg) prior to formalin testing. In the acute phase, CBD induced antinociception after administration of 30-100 mg/kg in males and 100 mg/kg in females and in the inflammatory phase at doses of 2.5-100 mg/kg in males and 10-100 mg/kg in females. In the acute phase, AT induced antinociception at 10 mg/kg for all mice, and at 0.3 mg/kg in males and 3 mg/kg in female mice in the inflammatory phase. Combining the calculated median effective doses of CBD and AT produced additive effects for all mice in the acute phase and for males only in the inflammatory phase. Use of selective serotonin 1A receptor antagonist N-[2-[4-(2-methoxyphenyl)-1 piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide (WAY-100635) maleate (0.1 mg/kg) before co-administration of CBD and AT reversed antinociception in the acute and partially reversed antinociception in the inflammatory phase. Administration of AT was found to enhance cannabinoid receptor type 1mRNA expression only in female mice. These results suggest a role for serotonin and sex in mediating cannabidiol and amitriptyline-induced antinociception in inflammatory pain. SIGNIFICANCE STATEMENT: Inflammatory pain is an important component of both acute and chronic pain. We have found that cannabidiol (CBD) and amitriptyline (AT) show dose-dependent, and that AT additionally shows sex-dependent, antinociceptive effects in an inflammatory pain model. Additionally, the combination of CBD and AT was found to have enhanced antinociceptive effects that is partially reliant of serotonin 1A receptors and supports the use of CBD within a multimodal approach to pain.

KLS-13019, a Novel Structural Analogue of Cannabidiol and GPR55 Receptor Antagonist, Prevents and Reverses Chemotherapy-Induced Peripheral Neuropathy in Rats.

Neuropathic pain is a form of chronic pain that develops because of damage to the nervous system. Treatment of neuropathic pain is often incompletely effective, and most available therapeutics have only moderate efficacy and present side effects that limit their use. Opioids are commonly prescribed for the management of neuropathic pain despite equivocal results in clinical studies and significant abuse potential. Thus, neuropathic pain represents an area of critical unmet medical need, and novel classes of therapeutics with improved efficacy and safety profiles are urgently needed. The cannabidiol structural analog and novel antagonist of GPR55, KLS-13019, was screened in rat models of neuropathic pain. Tactile sensitivity associated with chemotherapy exposure was induced in rats with once-daily 1-mg/kg paclitaxel injections for 4 days or 5 mg/kg oxaliplatin every third day for 1 week. Rats were then administered KLS-13019 or comparator drugs on day 7 in an acute dosing paradigm or days 7-10 in a chronic dosing paradigm, and mechanical or cold allodynia was assessed. Allodynia was reversed in a dose-dependent manner in the rats treated with KLS-13019, with the highest dose reverting the response to prepaclitaxel injection baseline levels with both intraperitoneal and oral administration after acute dosing. In the chronic dosing paradigm, four consecutive doses of KLS-13019 completely reversed allodynia for the duration of the phenotype in control animals. Additionally, coadministration of KLS-13019 with paclitaxel prevented the allodynic phenotype from developing. Together, these data suggest that KLS-13019 represents a potential new drug for the treatment of neuropathic pain. SIGNIFICANCE STATEMENT: Chemotherapy-induced peripheral neuropathy (CIPN) is a common, debilitating side effect of cancer treatment with no known cure. The GPR55 antagonist KLS-13019 represents a novel class of drug for this condition that is a potent, durable inhibitor of allodynia associated with CIPN in rats in both prevention and reversal-dosing paradigms. This novel therapeutic approach addresses a critical area of unmet medical need.