Cannabinoid Type Research Articles

Maladaptive Peripheral Ketogenesis in Schwann Cells Mediated by CB1R Contributes to Diabetic Neuropathy.

Diabetic peripheral neuropathy (DPN) is the most common complication of diabetes. Although studies have previously investigated metabolic disruptions in the peripheral nervous system (PNS), the exact metabolic mechanisms underlying DPN remain largely unknown. Herein, a specific form of metabolic remodeling involving aberrant ketogenesis within Schwann cells (SCs) in streptozotocin (STZ)-induced type I diabetes mellitus is identified. The PNS adapts poorly to such aberrant ketogenesis, resulting in disrupted energy metabolism, mitochondrial damage, and homeostatic decompensation, ultimately contributing to DPN. Additionally, the maladaptive peripheral ketogenesis is highly dependent on the cannabinoid type-1 receptor (CB1R)-Hmgcs2 axis. Silencing CB1R reprogrammed the metabolism of SCs by blocking maladaptive ketogenesis, resulting in rebalanced energy metabolism, reduced histopathological changes, and improved neuropathic symptoms. Moreover, this metabolic reprogramming can be induced pharmacologically using JD5037, a peripheral CB1R blocker. These findings revealed a new metabolic mechanism underlying DPN, and promoted CB1R as a promising therapeutic target for DPN.

Phytocanabinoids and synthetic cannabinoids: from recreational consumption to potential therapeutic use – a review

Cannabinoids are part of the most popular group of illicit substances in the Western world. The word “cannabinoid” refers to any chemical substance, regardless of structure or origin, that binds to the body’s cannabinoid receptors and that has effects similar to those produced by the Cannabis plant. Regarding their origin, cannabinoids can be classified into endocannabinoids, phytocannabinoids and synthetic cannabinoids. The behavioral and physiological effects of cannabinoids have received particular attention over the last few decades, including sensations of euphoria, relaxation and loss of concentration, with their repeated use being associated with short and long-term side effects, including respiratory and cardiovascular disorders, cognitive changes, psychoses, schizophrenia and mood disorders. On the other hand, recent investigations have proposed a promising therapeutic potential of cannabinoid-based drugs for a wide range of medical situations, including neurological and psychiatric disorders, among other indications. The growing popularity in the use of cannabinoid-based compounds, both for recreational and therapeutic purposes, has been accompanied by an equally continuous and growing evolution of knowledge regarding their potential harmful and beneficial effects. However, there are several open questions and challenges to be answered, which require more and better investigations. This article’s main objectives are: i) to understand the importance of the action of cannabinoids in humans; ii) identify the different types of cannabinoids that exist and understand the differences in their action; iii) distinguish the legislative framework for cannabinoid consumption; iv) identify the possible adverse effects of cannabinoid consumption, as well as their potential benefits; v) know the existing medical-scientific evidence in terms of therapeutic potential, particularly in relation to aspects of safety and efficacy; vi) encourage critical thinking about the recreational consumption and therapeutic use of cannabinoids, based both on currently available evidence and gaps in knowledge.

Cannabinoid-based Pharmacology for the Management of Substance Use Disorders.

In the last two decades, the endocannabinoid system has emerged as a crucial modulator of motivation and emotional processing. Due to its widespread neuroanatomical distribution and characteristic retrograde signaling nature, cannabinoid type I receptors and their endogenous ligands finely orchestrate somatic and axon terminal activity of dopamine neurons. Owing to these unique features, this signaling system is a promising pharmacological target to ameliorate dopamine-mediated drug-seeking behaviors while circumventing the adverse side effects of, for instance, dopaminergic antagonists. Despite considerable preclinical efforts, an agreement on the efficacy of endocannabinoid-targeting compounds for treating drug substance use disorders in humans has not been reached. In the following chapter, we will summarize preclinical and clinical evidence addressing the therapeutic potential of cannabinoids and endocannabinoid-targeting compounds in substance use disorders. To bridge the gap between animal and clinical research, we capitalize on studies evaluating the impact of endocannabinoid-targeting compounds in relevant settings, such as the management of drug relapse. Finally, we discuss the therapeutic potential of novel cannabinoid compounds that hold promise for treating substance use disorders.

Maladaptive changes in the homeostasis of AEA-TRPV1/CB1R induces pain-related hyperactivity of nociceptors after spinal cord injury

BackgroundNeuropathic pain resulting from spinal cord injury (SCI) is associated with persistent hyperactivity of primary nociceptors. Anandamide (AEA) has been reported to modulate neuronal excitability and synaptic transmission through activation of cannabinoid type-1 receptors (CB1Rs) and transient receptor potential vanilloid 1 (TRPV1). However, the role of AEA and these receptors in the hyperactivity of nociceptors after SCI remains unclear.ResultsIn this study, we investigated the effects of AEA and its receptors on the hyperexcitability of mouse dorsal root ganglion (DRG) neurons after SCI. Using a whole-cell patch-clamp technique, we found that the timing of SCI-induced hyperexcitability in nociceptors paralleled an increase in the endocannabinoid AEA content. The expression of TRPV1 and CB1R was also upregulated at different time points after SCI. High-dose extracellular administration of AEA increased the excitability of naive DRG neurons, leading to the transition from a rapidly accommodating (RA) hypoexcitable state to a highly excitable non-accommodating (NA) state. These AEA-induced transitions were facilitated by increased TRPV1 transcription. Pharmacological and Ca2+ imaging experiments revealed that AEA induced hyperexcitability in nociceptors after SCI via the AEA-TRPV1-Ca2+ pathway, whereas activation of CB1Rs reduced SCI-induced hyperexcitability and maintained cytosolic Ca2+ concentration ([Ca2+]cyto) at low levels in the early stages of SCI. As the AEA and TRPV1 levels increased after SCI, adaptive neuroprotection transitioned to a maladaptive hyperactive state, leading to sustained pain.ConclusionsTaken together, this study provides new insights into how endocannabinoids regulate nociceptor activity after SCI, offering potential targets for the treatment of neuropathic pain.

Cannabinoid type-1 receptors in CaMKII neurons drive impulsivity in pathological eating behavior.

Overconsumption of palatable food and energy accumulation are evolutionary mechanisms of survival when food is scarce. This innate mechanism becomes detrimental in obesogenic environment promoting obesity and related comorbidities, including mood disorders. The endocannabinoid system favors energy accumulation and regulates reward circuits. We applied a genetic strategy to reconstitute cannabinoid type-1 receptor (CB1) expression at functional levels specifically in CaMKII+neurons (CaMKII-CB1-RS) and adipocytes (Ati-CB1-RS), respectively, in a CB1 deficient background. Rescued CB1 expression in CaMKII+neurons, but not in adipocytes, promotes feeding behavior, leading to fasting-induced hyperphagia, increased motivation, and impulsivity to palatable food seeking. In a diet-induced obesity model, CB1 re-expression in CaMKII+neurons, but not in adipocytes, compared to complete CB1 deficiency, was sufficient to largely restore weight gain, food intake without any effect on glucose intolerance associated with high-fat diet consumption. In a model of glucocorticoid-mediated metabolic syndrome, CaMKII-CB1-RS mice showed all metabolic alterations linked to the human metabolic syndrome except of glucose intolerance. In a binge-eating model mimicking human pathological feeding, CaMKII-CB1-RS mice showed increased seeking and compulsive behavior to palatable food, suggesting crucial roles in foraging and an enhanced susceptibility to addictive-like eating behaviors. Importantly, other contingent behaviors, including increased cognitive flexibility and reduced anxiety-like behaviors, but not depressive-like behaviors, were also observed. To sum up, CB1 in CaMKII+neurons is instrumental in feeding behavior and energy storage under physiological conditions. The exposure to risk factors (hypercaloric diet, glucocorticoid dysregulation) leads to obesity, metabolic syndrome, binge-eating and food addiction.

Development and evaluation of deuterated [18F]JHU94620 isotopologues for the non-invasive assessment of the cannabinoid type 2 receptor in brain.

The cannabinoid type 2 receptors (CB2R) represent a target of increasing importance in neuroimaging due to its upregulation under various neuropathological conditions. Previous evaluation of [18F]JHU94620 for the non-invasive assessment of the CB2R availability by positron emission tomography (PET) revealed favourable binding properties and brain uptake, however rapid metabolism, and generation of brain-penetrating radiometabolites have been its main limitations. To reduce the bias of CB2R quantification by blood-brain barrier (BBB)-penetrating radiometabolites, we aimed to improve the metabolic stability by developing -d4 and -d8 deuterated isotopologues of [18F]JHU94620. The deuterated [18F]JHU94620 isotopologues showed improved metabolic stability avoiding the accumulation of BBB-penetrating radiometabolites in the brain over time. CB2R-specific binding with KD values in the low nanomolar range was determined across species. Dynamic PET studies revealed a CB2R-specific and reversible uptake of [18F]JHU94620-d8 in the spleen and to a local hCB2R(D80N) protein overexpression in the striatal region in rats. These results support further investigations of [18F]JHU94620-d8 in pathological models and tissues with a CB2R overexpression as a prerequisite for clinical translation.

Differential regulation of pruritic sensation and emotion by cannabinoid type 1 receptors on mPFC glutamatergic and GABAergic neurons.

Itch causes a strong urge to scratch and induces negative emotions, such as aversion and anxiety. Antihistamine medications are key in the clinical management of pruritus, but their therapeutic efficacy in controlling moderate and severe itching remains limited. The neural circuits in the brain that process itching and itch-induced aversion and anxiety remain unclear so far. Human brain imaging suggests that the medial prefrontal cortex (mPFC) is involved in processing the emotional and motivational components of itching. In this study, we investigated the mechanisms by which glutamatergic and GABAergic neurons in mPFC differentially regulated pruritic sensation and emotion through cannabinoid type 1 receptors (CB1Rs). Chloroquinoline (CQ)-induced acute and calcipotriol (MC903)-induced chronic itch models were established. Fiberoptic calcium imaging was used to detect the activity of the two types of neurons in response to itching. The CB1R antagonist AM251 (0.5 mg in 200 nL) was microinjected into the mPFC through the implanted cannula. We showed that chemogenetic activation of glutamatergic neurons and inhibition of GABAergic neurons in the mPFC reduced scratching and chronic itch-induced anxiety. GABAergic, but not glutamatergic, neurons were involved in acute itch-induced aversion. CB1Rs on glutamatergic and GABAergic neurons modulated chronic itch-induced scratching and anxiety in divergent manners. However, CB1Rs did not affect acute itch-induced scratching. CB1Rs on GABAergic, but not glutamatergic, neurons regulated acute itch-induced aversion. These results may guide the development of therapeutic strategies targeting CB1Rs to treat itch-induced sensory and emotional responses.

Therapeutic potential of agents targeting cannabinoid type 2 receptors in organ fibrosis.

The endocannabinoid system has garnered attention as a potential therapeutic target in a range of pathological disorders. Cannabinoid receptors type 2 (CB2) are a class of G protein-coupled receptors responsible for transmitting intracellular signals triggered by both endogenous and exogenous cannabinoids, including those derived from plants (phytocannabinoids) or manufactured synthetically (synthetic cannabinoids). Recent recognition of the role of CB2 receptors in fibrosis has fueled interest in therapeutic targeting of CB2 receptors in fibrosis. Fibrosis is characterized by the alteration of the typical cellular composition within the tissue parenchyma, resulting from exposure to diverse etiological factors. The pivotal function of CB2 agonists has been widely recognized in the regulation of inflammation, fibrogenesis, and various other biological pathologies. The modulation of CB2 receptors, whether by enhancing their expression or activating their function, has the potential to provide benefits in numerous conditions, particularly by avoiding any associated adverse effects on the central nervous system. The sufficient activation of CB2 receptors resulted in the complete suppression of gene expression related to transforming growth factor β1 and its subsequent fibrogenic response. Multiple reports have also indicated the diverse functions that CB2 agonists possess in mitigating chronic inflammation and subsequent fibrosis development in various types of tissues. While currently in the preclinical stage, the advancement of CB2 compounds has garnered significant attention within the realm of drug discovery. This review presents a comprehensive synthesis of various independent experimental studies elucidating the pivotal role of identified natural and synthetic CB2 agonists in the pathophysiology of organ fibrosis, specifically in the cardiac, hepatic, and renal systems.

Chronic cannabidiol administration modulates depressive and cognitive alterations induced by social isolation in male mice.

Cannabidiol (CBD), a non-psychotropic compound derived from Cannabis sativa, is known for its potential therapeutic effects on central nervous system (CNS) disorders. This study investigates the effects of chronic CBD administration on depressive and cognitive alterations induced by social isolation in male C57BL/6 mice. The experimental design involved adult mice subjected to either group housing or 12 weeks of social isolation. Behavioral assessments, including the sucrose preference test, open field test, light/dark box, novel object recognition, and tail suspension test, were performed to evaluate the impact of CBD on emotional and cognitive alterations. Additionally, hippocampal gene expression for cannabinoid type 1 receptors (CB1R), serotonin type 1A receptors (5HT1AR), and brain-derived neurotrophic factor (BDNF) were analyzed. Results indicate that CBD mitigated anhedonia in isolated mice and reduced immobility episodes in the TST. However, CBD did not exert significant anxiolytic effects and unexpectedly induced anxiety-like behavior in group-housed mice. The study also revealed that social isolation impaired recognition memory and reduced BDNF expression, while CBD treatment protected memory in isolated mice. These findings suggest that CBD has potential antidepressant and neuroprotective effects in social isolation-induced depressive models, although its anxiogenic effects in non-stressed mice warrant further investigation.

Unraveling GPCRs Allosteric Modulation. Cannabinoid 1 Receptor as a Case Study.

G-protein-coupled receptors (GPCRs) constitute one of the most prominent families of integral membrane receptor proteins that mediate most transmembrane signaling processes. Malfunction of these signal transduction processes is one of the underlying causes of many human pathologies (Parkinson's, Huntington's, heart diseases, etc), provoking that GPCRs are the largest family of druggable proteins. However, these receptors have been targeted traditionally by orthosteric ligands, which usually causes side effects due to the simultaneous targeting of homologous receptor subtypes. Allosteric modulation offers a promising alternative approach to circumvent this problematic and, thus, comprehending its details is a most important task. Here we use the Cannabinoid type-1 receptor (CB1R) in trying to shed light on this issue, focusing on positive allosteric modulation. This is done by using the protein-dipole Langevin-dipole (PDLD) within the linear response approximation (LRA) framework (PDLD/S-2000) along with our coarse-grained (CG) model of membrane proteins to evaluate the dissociation constants (KBs) and cooperativity factors (αs) for a diverse series of CB1R positive allosteric modulators belonging to the 2-phenylindole structural class, considering CP55940 as an agonist. The agreement with the experimental data evinces that significantly populated allosteric modulator:CB1R and allosteric modulator:CP55940:CB1R complexes have been identified and characterized successfully. Analyzing them, it has been determined that CB1R positive allosteric modulation lies in an outwards displacement of transmembrane α helix (TM) 4 extracellular end and in the regulation of the range of motion of a compound TM7 movement for binary and ternary complexes, respectively. In this respect, we achieved a better comprehension of the molecular architecture of CB1R positive allosteric site, identifying Lys1923.28 and Gly1943.30 as key residues regarding electrostatic interactions inside this cavity, and to rationalize (at both structural and molecular level) the exhibited stereoselectivity in relation to positive allosteric modulation activity by considered CB1R allosteric modulators. Additionally, putative/postulated allosteric binding sites have been screened successfully, identifying the real CB1R positive allosteric site, and most structure-activity relationship (SAR) studies of CB1R 2-phenylindole allosteric modulators have been rationalized. All these findings point out towards the predictive value of the methodology used in the current work, which can be applied to other biophysical systems of interest. The results presented in this study contribute significantly to understand GPCRs allosteric modulation and, hopefully, will encourage a more thorough exploration of the topic.

Fatty acid-binding protein 7 gene deletion promotes decreases in brain cannabinoid type 1 receptor binding

Fatty acid-binding protein 7 (FABP7) aids in the intracellular transport of endogenous cannabinoids and is involved in regulating the stress response system. This study examined the role of FABP7 in chronic stress exposure through the binding of CB1 receptors. Adult male FABP7+/+ and FABP7-/- mice were treated with the unpredictable chronic mild stress (UCMS) procedure. After 28 days of treatment, mice were euthanized, and CB1 was measured with in vitro autoradiography using [3H] SR141716A. FABP7-/- mice, irrespective of stress treatment, showed reduced [3H] SR141716A binding in the amygdala, secondary somatosensory cortex, and ventral caudate putamen compared with the FABP7+/+ mice. Additionally, FABP7-/- mice treated with UCMS exhibited a reduction in CB1 binding in the globus pallidus and ventral caudate putamen compared with UCMS-treated FABP7+/+ mice. Genetic deletion of FABP7 can decrease CB1 expression in various brain regions; however, the underlying mechanism remains unclear.

Hippocampal cannabinoid type 2 receptor alleviates chronic neuropathic pain-induced cognitive impairment via microglial DUSP6 pathway in rats.

Approximately 50% of patients with chronic neuropathic pain experience cognitive impairment, which negatively impacts their quality of life. The cannabinoid type 2 receptor (CB2R) may be involved in hippocampal cognitive processes. However, its role in chronic neuropathic pain-induced cognitive impairment remains elusive. Spared nerve injury (SNI) was used to induce chronic neuropathic pain in rats, while the novel-object recognition test and the Y-maze test were employed to assess cognitive function. Immunofluorescence, western blotting, and stereotaxic hippocampal microinjection were utilized to elucidate the potential mechanisms. We observed a reduction in mechanical pain threshold and cognitive impairment in SNI rats. This was accompanied by a tendency for hippocampal microglia to adopt pro-inflammatory functions. Notably, no changes were detected in CB2R expression. However, downregulation of the endogenous ligands AEA and 2-AG was evident. Hippocampal microinjection of a CB2R agonist mitigated cognitive impairment in SNI rats, which correlated with a tendency for microglia to adopt anti-inflammatory functions. Additionally, SNI-induced activation of the p-ERK/NFκB pathway in the hippocampus. Activation of CB2R reversed this process by upregulating DUSP6 expression in microglia. The effects elicited by CB2R activation could be inhibited through the downregulation of microglial DUSP6 via hippocampal adeno-associated virus (AAV) microinjection. Conversely, overexpression of hippocampal DUSP6 using AAV ameliorated the cognitive deficits observed in SNI rats, which remained unaffected by the administration of a CB2R antagonist. Our findings demonstrate that activation of hippocampal CB2R can mitigate chronic neuropathic pain-induced cognitive impairment through the modulation of the DUSP6/ERK/NFκB pathway.

Cannabinoid Type 1 Receptor Antagonist Impaired Spatial Memory and Increased the Tau Gene Expression in Animal Model of the Alzheimer's disease

Alzheimer's disease is a neurodegenerative disease characterized by the accumulation of two different proteins, β-amyloid and tau. The present study aimed to scrutinize the effects of bilateral administration of the cannabinoid receptor antagonist (AM251) in the hippocampus on spatial memory and tau gene expression in an Alzheimer's disease model. β-amyloid toxin was injected bilaterally into the hippocampus of Wistar male rats to induce Alzheimer's disease, and the rats were then categorized into the control group (receiving distilled water as β-amyloid toxin solvent), lesion group (receiving β-amyloid toxin), β-amyloid + DMSO group (as antagonist solvent of AM251), and AM251 antagonist receiving groups (5, 25, and 100 ng). During the training course of the Morris water maze test, the antagonist of the cannabinoid 1 receptor AM251 was injected bilaterally into the hippocampus for four days at doses of 5, 25, and 100 ng. To assess the spatial memory of the animals, the parameters of the distance traveled by the animals, latency time to reach the hidden platform, velocity of the animals, and tau gene expression in real time were analyzed. The spatial memory indices were impaired after injection of β-amyloid and AM251 cannabinoid antagonist. The mRNA expression of tau protein increased following the injection of β-amyloid toxin, but there was no significant difference between the cannabinoid antagonist and β-amyloid groups. These results indicate the destructive effect of beta-amyloid toxin on spatial memory, as well as the positive role of the cannabinoid system in memory formation and consolidation, although further studies are warranted in this regard.

Impact of cannabinoids on synapse markers in an SH-SY5Y cell culture model

Patients suffering from schizophrenic psychosis show reduced synaptic connectivity compared to healthy individuals, and often, the use of cannabis precedes the onset of schizophrenic psychosis. Therefore, we investigated if different types of cannabinoids impact methylation patterns and expression of schizophrenia candidate genes concerned with the development and preservation of synapses and synaptic function in a SH-SY5Y cell culture model. For this purpose, SH-SY5Y cells were differentiated into a neuron-like cell type as previously described. Effects of the cannabinoids delta-9-THC, HU-210, and Anandamide were investigated by analysis of cell morphology and measurement of neurite/dendrite lengths as well as determination of methylation pattern, expression (real time-qPCR, western blot) and localization (immunocytochemistry) of different target molecules concerned with the formation of synapses. Regarding the global impression of morphology, cells, and neurites appeared to be a bit more blunted/roundish and to have more structures that could be described a bit boldly as resembling transport vesicles under the application of the three cannabinoids in comparison to a sole application of retinoic acid (RA). However, there were no obvious differences between the three cannabinoids. Concerning dendrites or branch lengths, there was a significant difference with longer dendrites and branches in RA-treated cells than in undifferentiated control cells (as shown previously), but there were no differences between cannabinoid treatment and exclusive RA application. Methylation rates in the promoter regions of synapse candidate genes in cannabinoid-treated cells were in between those of differentiated cells and untreated controls, even though findings were significant only in some of the investigated genes. In other targets, the methylation rates of cannabinoid-treated cells did not only approach those of undifferentiated cells but were also valued even beyond. mRNA levels also showed the same tendency of values approaching those of undifferentiated controls under the application of the three cannabinoids for most investigated targets except for the structural molecules (NEFH, MAPT). Likewise, the quantification of expression via western blot analysis revealed a higher expression of targets in RA-treated cells compared to undifferentiated controls and, again, lower expression under the additional application of THC in trend. In line with our earlier findings, the application of RA led to higher fluorescence intensity and/or a differential signal distribution in the cell in most of the investigated targets in ICC. Under treatment with THC, fluorescence intensity decreased, or the signal distribution became similar to the dispersion in the undifferentiated control condition. Our findings point to a decline of neuronal differentiation markers in our in vitro cell-culture system under the application of cannabinoids.

Cannabis-Derived Product Types, Flavors, and Compound Types From an E-Commerce Website

Cannabis-derived products (CDPs) are widely available and diverse. A classification of product and flavor types is necessary to establish a foundation for comparative research, although research aiming to classify cannabis in its variety of products, flavors, and cannabinoid compounds based on public online e-commerce data is lacking. To analyze data from a large cannabis e-commerce marketplace to identify and characterize cannabis product types, flavors, and compound types. This qualitative study was conducted in 2 phases: (1) data mining of the cannabis e-commerce website Weedmaps for product listings in the US between September 1 and November 30, 2023 and (2) grouping CDPs into product, flavor, and cannabinoid compound categories. Cannabis product listings. Product listings and descriptions were extracted from the platform. Coding was performed for specific product characteristics, routes of administration (ROAs), and characterization of flavors. A total of 573 854 unique US CDP sales listings from the platform were collected; after removing 72 842 nonconsumable items, 501 012 were analyzed. Product ROAs included multisystem (205 637 [41.04%]), respiratory (185 296 [36.98%]), digestive (98 941 [19.75%]), epidermal (9487 [1.89%]), and oral (1651 [0.33%]). Nearly half (210 575 [42.03%]) of all product listings included at least 1 flavor, with 247 762 instances of flavors. The 3 most common flavors were lemon (22 106 [8.92%]), cake (19 463 [7.86%]), and strawberry (13 961 [5.63%]). The most common cannabinoid compound type was Δ9-tetrahydrocannabinol (54 699 [63.30%]). This qualitative study categorized more than half a million CDPs for product and flavor types. Results are needed for comparative studies on product and market availability and can help in assessing concerns about appealing characteristics. The results can also inform future market surveillance efforts aimed at identifying new and emerging products as cannabis policy continues to move toward greater legalization.

Assessment of pharmacological effects and abuse potential of 5F-EDMB-PICA, CUMYL-PEGACLONE, and NM-2201 in mice.

The newly emerging synthetic cannabinoids (SCs) 5F-EDMB-PICA, CUMYL-PEGACLONE, and NM-2201 have been observed to produce effects by activating cannabinoid type 1 (CB1) receptors. Nevertheless, the pharmacological effects and potential for abuse of these three substances remain to be studied. These substances have yet to be regulated in many countries. We investigated the safety, pharmacological effects, rewarding effects, and cannabinoid withdrawal of 5F-EDMB-PICA, CUMYL-PEGACLONE, and NM-2201. This study evaluated the drug safety and the cannabinoid-specific pharmacological effects of the three substances through acute toxicity experiments (in which the LD50 of each substance was obtained) and tetrad experiments (comprising assessments of hypothermia, analgesia, locomotion inhibition, and catalepsy). Furthermore, the conditioned place preference (CPP) experiments and withdrawal experiments were conducted to evaluate the rewarding effect and cannabinoid withdrawal potential of the substances in question. The results demonstrated that all three drugs exhibited certain acute toxic effects and could potentially induce tetrad effects. The data were analyzed using non-linear regression, and the corresponding ED50 values and 95% confidence intervals (CI) were obtained. The rank order of potency was determined to be CUMYL-PEGACLONE > 5F-EDMB-PICA > NM-2201. In the CPP experiments, it was demonstrated that 5F-EDMB-PICA significantly induced an increase in CPP score at a dose of 0.3mg/kg, while NM-2201 caused an increase in CPP score and a significant aversion effect at a dose of 2 and 3mg/kg, respectively. It is noteworthy that all three types of SCs were observed to produce a significant biphasic effect, indicating that CPP scores were biphasic for all compounds. Following the administration of the CB1 receptor antagonist rimonabant, a notable increase in head twitches and paw tremors was observed, indicating that these three SCs induce cannabinoid withdrawal through the mediation of CB1 receptors. The results of this study indicated that these SCs possess cannabinoid-specific pharmacological effects and abuse potential, which provides substantial experimental data to support the future regulation of these substances.

Lack of Cannabinoid Type 2 Promoter Activity in Normal or Injured Kidneys Using a Cnr2-GFP Reporter Mouse.

Introduction: Although cannabinoid type 2 (CB2) receptor activity is known to promote diverse biological functions in the kidney, published data regarding CB2 receptor protein levels and cellular distribution within the kidney is inconsistent. The goal of the present study was to investigate the changes of CB2 in the kidney obtained from mice exposed to various forms of kidney injury using a genetic mouse model expressing green fluorescent protein (GFP) driven by the endogenous cannabinoid receptor 2 (Cnr2) promoter. Materials and Methods: Kidney injury was established in a genetic mouse model expressing green fluorescent protein (GFP) driven by the endogenous Cnr2 promoter. Kidney injury was initiated by either treatment with different chemicals [cisplatin or lipopolysaccharide (LPS)] or by unilateral ureteral obstruction (UUO). Changes in the detection of GFP were used as a proxy for CB2 levels and localization. Histological changes due to the injury stimuli were observed by time-related, morphological changes in kidney cytoarchitecture and blood parameters, such as serum creatinine levels. Cnr2 mRNA levels were detected by reverse transcription coupled to polymerase chain reaction (RT-PCR) while protein changes in the tissue lysates were measured by Western blot analysis. Cellular localization of GFP was detected by fluorescent microscopy. Results: Our data demonstrated that there was no band or a minimally detectable band for GFP using kidney lysates from vehicle- or cisplatin-treated mice. A similar lack of GFP was detected in the UUO kidney versus the contralateral control kidney. This is consistent with the low, albeit detectable levels of Cnr2 mRNA in the kidney samples from control or cisplatin treatment. In frozen kidney sections from vehicle and cisplatin-treated mice, GFP fluorescence was not detectable in tubular epithelia, glomeruli or blood vessels in the cortex. Instead, GFP was detected in rare cells within the interstitial space. A second chemical injury model using LPS found a similar lack of GFP protein levels and an absence of legitimate GFP fluorescence in the main cell types within the kidney. Conclusion: These findings suggest that Cnr2 promoter activity is minimally active in normal or injured kidneys, and that pharmacological manipulation of CB2 receptors may be associated with receptors being expressed in cells recruited to the kidney.

New peripherally-restricted CB1 receptor antagonists, PMG-505–010 and −013 ameliorate obesity-associated NAFLD and fibrosis

The endocannabinoid system plays a crucial role in metabolic regulation, prompting the investigation of cannabinoid type 1 receptor (CB1R) antagonists for obesity and its complications like non-alcoholic fatty liver disease (NAFLD). Concerns over psychiatric side effects led to the development of peripheral CB1R antagonists that circumvent the blood-brain barrier (BBB). In this study, we synthesized PMG-505–010 and PMG-505–013 as peripherally restricted CB1 receptor antagonists by modifying rimonabant to minimize BBB penetration. Physicochemical analysis confirmed their reduced lipophilicity and increased polarity compared to rimonabant, indicating limited brain exposure. Molecular docking studies revealed similar binding modes to rimonabant at CB1R, characterized by robust hydrophobic interactions. Functionally, they acted as CB1R antagonists and inverse agonists, effectively reversing CP55,940-induced cAMP inhibition. In a murine model of obesity-related NAFLD, PMG-505–010 and −013 improved metabolic profiles, including fasting blood glucose levels and dyslipidemia. They also ameliorated hepatic injury, steatosis, and inflammation, evidenced by reduced liver enzymes, lipid peroxidation, hepatic lipid levels, and inflammatory cytokine levels. Notably, these compounds inhibited hepatic fibrosis by reducing extracellular matrix (ECM) deposition and altering fibrosis-related gene and protein expressions. In conclusion, PMG-505–010 and PMG-505–013 hold promise for treating obesity-related liver diseases, including NAFLD and fibrosis, through selective peripheral CB1R targeting, potentially avoiding CNS-related side effects seen with earlier CB1R antagonists.

Understanding Medical Cannabis: A Simple Guide to CBD and THC

There is an ongoing debate in the literature about the place of cannabinoid therapy in everyday clinical practice. The overview examined systematic reviews and meta-analyses on the use of medical marijuana (MM) in specific or diseases, such as epilepsy, multiple sclerosis, pain, nausea and vomiting during chemotherapy, cachexia, and sleep disorders. We analyzed different cannabinoids like CBD, THC, dronabinol, nabilone, and THC:CBD combinations (Nabiximol) to understand their effects on various medical conditions, dose effectiveness, and side effects. CBD showed promise epilepsy, Nabilone showed a significant reduction in pain and insomnia, Nabiximol has been effective in reducing spasticity, pain, and sleep disturbance in multiple sclerosis patients. Nabilone and dronabinol improve nausea and vomiting due to chemotherapy, but the evidence is low. The results on the effectiveness of MM in the treatment of cachexia and cancer pain are inconclusive. Outcomes suggest that side effects typically were mild to moderate in severity. The type of cannabinoid (including CBD and THC content) and amount of dose, were found to potentially influence the results obtained in the trials, affecting both the effectiveness and the side effects experienced by patients. Young people, elderly, and children are particularly vulnerable and, despite ongoing research in these age groups, we still know too little about whether and in which clinical conditions the use of medical cannabis is justified. The analyzed studies faced limitations due to heterogeneity in methodology, dosages, and outcome measures and highlighting potential controversies in interpreting the results, so further research is needed.

Abnormal developmental of hippocampal subfields and amygdalar subnuclei volumes in young adults with heavy cannabis use: A three-year longitudinal study

BackgroundDifferences in the volumes of the hippocampus and amygdala have consistently been observed between young adults with heavy cannabis use relative to their non-using counterparts. However, it remains unclear whether the subfields of these functionally and structurally heterogenous regions exhibit similar patterns of change in young adults with long-term heavy cannabis use disorder (CUD). ObjectivesThis study aims to investigate the effects of long-term heavy cannabis use in young adults on the subregional structures of the hippocampus and amygdala, as well as their longitudinal alterations. MethodsThe study sample comprised 20 young adults with heavy cannabis use and 22 matched non-cannabis using healthy volunteers. All participants completed the Cannabis Use Disorder Identification Test (CUDIT) and underwent two T1-structural magnetic resonance imaging (MRI) scans, one at baseline and another at follow-up 3 years later. The amygdala, hippocampus, and their subregions were segmented on T1-weighted anatomical MRI scans, using a previously validated procedure. ResultsAt baseline, young adults with heavy CUD exhibited significantly larger volumes in several hippocampal (bilateral presubiculum, subiculum, Cornu Ammonis (CA) regions CA1, CA2-CA3, and right CA4-Dentate Gyrus (DG)) and amygdala (bilateral paralaminar nuclei, right medial nucleus, and right lateral nucleus) subregions compared to healthy controls, but these differences were attenuated at follow-up. Longitudinal analysis revealed an accelerated volumetric decrease in these subregions in young adults with heavy CUD relative to controls. Particularly, compared to healthy controls, significant accelerated volume decreases were observed in the right hippocampal subfields of the parasubiculum, subiculum, and CA4-DG. In the amygdala, similar trends of accelerated volumetric decreases were observed in the left central nucleus, right paralaminar nucleus, right basal nucleus, and right accessory basal nucleus. ConclusionsThe current findings suggest that long-term heavy cannabis use impacts maturational process of the amygdala and hippocampus, especially in subregions with high concentrations of cannabinoid type 1 receptors (CB1Rs) and involvement in adult neurogenesis.