Category Archives: Endocannabinoid System

Yin and yang of cannabinoid CB1 receptor: CB1 deletion in immune cells causes exacerbation while deletion in non-immune cells attenuates obesity

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“While blockade of cannabinoid receptor 1 (CB1) has been shown to attenuate diet-induced obesity (DIO), its relative role in different cell types has not been tested. The current study investigated the role of CB1 in immune vs non-immune cells during DIO by generating radiation-induced bone marrow chimeric mice that expressed functional CB1 in all cells except the immune cells or expressed CB1 only in immune cells. CB1-/- recipient hosts were resistant to DIO, indicating that CB1 in non-immune cells is necessary for induction of DIO. Interestingly, chimeras with CB1-/- in immune cells showed exacerbation in DIO combined with infiltration of bone-marrow-derived macrophages to the brain and visceral adipose tissue, elevated food intake, and increased glucose intolerance. These results demonstrate the opposing role of CB1 in hematopoietic versus non-hematopoietic cells during DIO and suggests that targeting immune CB1 receptors provides a new pathway to ameliorate obesity and related metabolic disorders.”

https://pubmed.ncbi.nlm.nih.gov/36093055/

https://www.cell.com/iscience/fulltext/S2589-0042(22)01266-4?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2589004222012664%3Fshowall%3Dtrue

Peripheral CB1 receptor blockade acts as a memory enhancer through a noradrenergic mechanism

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Neuropsychopharmacology

“Peripheral inputs continuously shape brain function and can influence memory acquisition, but the underlying mechanisms have not been fully understood. Cannabinoid type-1 receptor (CB1R) is a well-recognized player in memory performance, and its systemic modulation significantly influences memory function. By assessing low arousal/non-emotional recognition memory in mice, we found a relevant role of peripheral CB1R in memory persistence. Indeed, the peripherally-restricted CB1R specific antagonist AM6545 showed significant mnemonic effects that were occluded in adrenalectomized mice, and after peripheral adrenergic blockade. AM6545 also transiently impaired contextual fear memory extinction. Vagus nerve chemogenetic inhibition reduced AM6545-induced mnemonic effect. Genetic CB1R deletion in dopamine β-hydroxylase-expressing cells enhanced recognition memory persistence. These observations support a role of peripheral CB1R modulating adrenergic tone relevant for cognition. Furthermore, AM6545 acutely improved brain connectivity and enhanced extracellular hippocampal norepinephrine. In agreement, intra-hippocampal β-adrenergic blockade prevented AM6545 mnemonic effects. Altogether, we disclose a novel CB1R-dependent peripheral mechanism with implications relevant for lengthening the duration of non-emotional memory.”

https://pubmed.ncbi.nlm.nih.gov/36088492/

https://www.nature.com/articles/s41386-022-01436-9

Endocannabinoid System and the Otolaryngologist

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Otolaryngologic Clinics of North America

“The endocannabinoid system is located throughout the central and peripheral nervous systems, endocrine system, gastrointestinal system, and within inflammatory cells. The use of medical cannabinoids has been gaining traction as a viable treatment option for varying illnesses in recent years. Research is ongoing looking at the effect of cannabinoids for treatment of common otolaryngologic pathologies. This article identifies common otolaryngologic pathologies where cannabinoids may have benefit, discusses potential drawbacks to cannabinoid use, and suggests future directions for research in the application of medical cannabinoids.”

https://pubmed.ncbi.nlm.nih.gov/36088164/

https://www.sciencedirect.com/science/article/abs/pii/S0030666522000767?via%3Dihub

Phytocannabinoids regulate inflammation in IL-1β-stimulated human gingival fibroblasts

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Journal of Periodontal Research

“Objectives: Billions of individuals worldwide suffer from periodontal disease, an inflammatory disease that results in hard-tissue and soft-tissue destruction. A viable therapeutic option to treat periodontal disease may be via cannabinoids that exert immunomodulatory effects, and the endocannabinoid system (ECS) is readily present in periodontal tissues that exhibit cannabinoid type 1 and 2 receptors (CB1R and CB2R). Phytocannabinoids (pCBs), which are a part of a heterogeneous group of molecules acting on cannabinoid receptors (CBR) derived from the cannabis plants, have been attributed to a wide variety of effects including anti-inflammatory activity and some pro-inflammatory effects depending on the cell type. Thus, this study aims to examine the effects of pCBs on primary human gingival fibroblasts (HGFs) in IL-1β stimulated (simulated periodontal disease) HGFs.

Results: Cannabidivarin (CBVN or CBDV) (EC50 = 12 nM) and cannabigerol (CBG) (EC50 = 30 nM) exhibited agonist activity on CB2R with intermediate efficacy. Cannabidiol (CBD) did not exhibit activation of the CB2R, and the CB1R activation was not observed with any of the pCBs. Cytotoxicity results showed that concentrations of 2.50 μg/ml or greater for the pCBs were toxic except for CBVN. Lower concentrations of CBD and CBG (0.1-0.75 μg/ml), and CBVN at 2.50 μg/ml exhibited significant effects on HGF proliferation. In IL-1β-stimulated HGFs, prostaglandin E2 (PGE2) production was significantly suppressed only by CBG and CBVN. CBD and CBG treatment alone did, however, elevate PGE2 production significantly compared to control. IL-1β stimulation resulted in a robust increase in the production of all cytokines tested. Treatment of IL-β-stimulated HGF with the three pCBs (1 μg/ml) significantly reduced INF-ɣ, TNF-α, and IL-2. The significant suppression of IL-4 was seen with CBD and CBVN, while only CBVN exerted suppression of IL-13. The three pCBs significantly increased IL-6, IL-10, and IL-12 levels, while none of the pCBs reduced the expression of IL-8 in IL-1β-stimulated HGF.

Conclusion: The effective inhibition of IL-1β-stimulated production of PGE2 and cytokines by the pCB in HGFs suggests that targeting the endocannabinoid system may lead to the development of therapeutic strategies for periodontal therapy. However, each pCB has its unique anti-inflammatory profile, in which certain pro-inflammatory activities are also exhibited. The pCBs alone or in combination may benefit and aid in improving public oral health.”

https://pubmed.ncbi.nlm.nih.gov/36070347/

https://onlinelibrary.wiley.com/doi/10.1111/jre.13050

Cannabidiol impairs fear memory reconsolidation in female rats through dorsal hippocampus CB1 but not CB2 receptor interaction

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European Neuropsychopharmacology

“Women present increased susceptibility to anxiety- and stress-related disorders compared to men. A potentially promising pharmacological-based strategy to regulate abnormal aversive memories disrupts their reconsolidation stage after reactivation and destabilization.

Male rodent findings indicate that cannabidiol (CBD), a relatively safe and effective treatment for several mental health conditions, can impair the reconsolidation of aversive memories. However, whether and how CBD influences it in females is still unknown.

The present study addressed this question in contextually fear-conditioned female rats.

We report that systemically administered CBD impaired their reconsolidation, reducing freezing expression for over a week. This action was restricted to a time when the reconsolidation presumably lasted (< six hours post-retrieval) and depended on memory reactivation/destabilization. Moreover, the impairing effects of CBD on memory reconsolidation relied on the activation of cannabinoid type-1 but not type-2 receptors located in the CA1 subregion of the dorsal hippocampus.

CBD applied directly to this brain area was sufficient to reproduce the effects of systemic CBD treatment. Contextual fear memories attenuated by CBD did not show reinstatement, an extinction-related feature. By demonstrating that destabilized fear memories are sensitive to CBD and how it hinders mechanisms in the DH CA1 that may restabilize them in female rats, the present findings concur that reconsolidation blockers are viable and could be effective in disrupting abnormally persistent and distressing aversive memories such as those related to posttraumatic stress disorder.”

https://pubmed.ncbi.nlm.nih.gov/36049316/

https://www.sciencedirect.com/science/article/abs/pii/S0924977X22008367?via%3Dihub

Cross-talk between neurosteroid and endocannabinoid systems in cannabis addiction

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“Steroids and endocannabinoids are part of two modulatory systems and some evidence has shown their interconnections in several functions.

Homeostasis is a common steady-state described in the body, which is settled by regulatory systems to counterbalance deregulated or allostatic set points towards an equilibrium. This regulation is of primary significance in the central nervous system for maintaining neuronal plasticity and preventing brain-related disorders.

In this context, the recent discovery of the shutdown of the endocannabinoid system (ECS) overload by the neurosteroid pregnenolone has highlighted new endogenous mechanisms of ECS regulation related to cannabis-induced intoxication.

These mechanisms involve a regulatory loop mediated by overactivation of the central type-1 cannabinoid receptor (CB1R), which triggers the production of its own regulator, pregnenolone. Therefore, this highlights a new process of regulation of steroidogenesis in the brain.

Pregnenolone, long considered an inactive precursor of neurosteroids, can then act as an endogenous negative allosteric modulator of CB1R. The present review aims to shed light on a new framework for the role of ECS in the addictive characteristics of cannabis with the novel endogenous mechanism of ECS involving the neurosteroid pregnenolone.

In addition, this new endogenous regulatory loop could provide a relevant therapeutic model in the current context of increasing recreational and medical use of cannabis.”

https://pubmed.ncbi.nlm.nih.gov/36043319/

https://onlinelibrary.wiley.com/doi/10.1111/jne.13191

“Pregnenolone blocks cannabinoid-induced acute psychotic-like states in mice”

https://pubmed.ncbi.nlm.nih.gov/28220044/

“Pregnenolone Can Protect the Brain from Cannabis Intoxication”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4057431/

Cannabinoids receptors in Covid-19: Perpetrators and victims

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“COVID-19 is caused by SARS-CoV-2 and leads to acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and extrapulmonary manifestations in severely affected cases. However, most of the affected cases are mild or asymptomatic.

Cannabinoids (CBs) such as tetrahydrocannabinol (THC) and cannabidiol (CBD), which act on G-protein-coupled receptors called CB1 and CB2, have anti-inflammatory effects. Many published studies show that CBs are effective in various inflammatory disorders, viral infections, and attenuation of ALI and ARDS.

Therefore, the aim of the present narrative review was to summarize the possible immunological role of CBs in COVID-19. The effects of CBs are controversial, although they have beneficial effects via CB2 receptors and adverse effects via CB1 receptors against ALI, ARDS, and hyperinflammation, which are hallmarks of COVID-19.

The present narrative review has shown that CBs effectively manage ALI and ARDS by suppressing pro-inflammatory cytokines, which are common in COVID-19. Therefore, CBs may be used to manage COVID-19 because of their potent anti-inflammatory effects with suppression of pro-inflammatory cytokines and inhibition of inflammatory signaling pathways.”

https://pubmed.ncbi.nlm.nih.gov/36043749/

https://www.eurekaselect.com/article/125986

Analysis of Potential Anti-Cancer Effects of Cannabinol and Cannabidiol using HCC1806 and HEK293 Cell Lines

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URSCA 2018

“Humans produce endocannabinoids that act as neuromodulators in the endocannabinoid system. They bind to Gαi protein-coupled cannabinoid receptors to control the release of many neurotransmitters. Cannabinoids receptor 1 (CB1) mediates psychoactive effects through its location mostly in the central nervous system while Cannabinoid receptor 2 (CB2) regulates various immune responses through its location in peripheral tissues.

The endocannabinoid system has been used as a molecular target by research to treat diseases such as multiple sclerosis, cardiovascular disorders, obesity and inflammatory pain. Thus, the endocannabinoid system is a potential molecular target to treat cancer. With the proposed legalization of recreational marijuana and with growing number of patients using cannabis for medicinal purpose, there is an urgent need to provide data on potential medicinal value of cannabis and cannabinoids.

The Cannabis Sativa plant naturally synthesizes numerous different cannabinoids of which (CBN) and cannabidiol (CBD) have promising properties in cancer treatment. CBD is a phytocannabinoid known for its anticonvulsant and anti-nausea properties. Previous research suggests that CBD can target breast cancer cells while preserving normal cells. CBN is another phyotocannabinoid with anti-inflammatory properties that can potentially aid to reduce inflammation resulting from cancer.

This study aims to determine if CBN and CBD have an effect on cancer cells and normal cells. We hypothesize that we may observe an increase in apoptosis of cancer cells treated with the two compounds but no effect or perhaps even a slight increase in normal cell growth. Preliminary data in lab suggests that these compounds have anti-cancer properties and we want to solidify this evidence through repetition of the experiment.”

https://journals.macewan.ca/ursca/article/view/1582

Cannabinoids and Chronic Liver Diseases

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ijms-logo

“Nonalcoholic fatty liver disease (NAFLD), alcohol-induced liver disease (ALD), and viral hepatitis are the main causes of morbidity and mortality related to chronic liver diseases (CLDs) worldwide. New therapeutic approaches to prevent or reverse these liver disorders are thus emerging.

Although their etiologies differ, these CLDs all have in common a significant dysregulation of liver metabolism that is closely linked to the perturbation of the hepatic endocannabinoid system (eCBS) and inflammatory pathways. Therefore, targeting the hepatic eCBS might have promising therapeutic potential to overcome CLDs.

Experimental models of CLDs and observational studies in humans suggest that cannabis and its derivatives may exert hepatoprotective effects against CLDs through diverse pathways. However, these promising therapeutic benefits are not yet fully validated, as the few completed clinical trials on phytocannabinoids, which are thought to hold the most promising therapeutic potential (cannabidiol or tetrahydrocannabivarin), remained inconclusive. Therefore, expanding research on less studied phytocannabinoids and their derivatives, with a focus on their mode of action on liver metabolism, might provide promising advances in the development of new and original therapeutics for the management of CLDs, such as NAFLD, ALD, or even hepatitis C-induced liver disorders.”

https://pubmed.ncbi.nlm.nih.gov/36012687/

“Given the significant contribution of the hepatic eCBS and its downstream pathways in the regulation of liver metabolism and the setting of liver abnormalities, pharmacologically targeting peripheral CBRs may have promising potential therapeutic benefits for the treatment of CLDs. Besides this, the use of cannabis by people at risk of developing chronic liver disorders has also suggested hepatoprotective effects by reducing the frequency of NAFLD, ALD, or HCV-induced liver disorders, which would suggest that cannabinoid-based medicine may be effective in treating CLDs.”

https://www.mdpi.com/1422-0067/23/16/9423/htm

Cannabinoids and PPAR Ligands: The Future in Treatment of Polycystic Ovary Syndrome Women with Obesity and Reduced Fertility

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“Cannabinoids (CBs) are used to treat chronic pain, chemotherapy-induced nausea and vomiting, and multiple sclerosis spasticity. Recently, the medicinal use of CBs has attracted increasing interest as a new therapeutic in many diseases.

Data indicate a correlation between CBs and PPARs via diverse mechanisms. Both the endocannabinoid system (ECS) and peroxisome proliferator-activated receptors (PPARs) may play a significant role in PCOS and PCOS related disorders, especially in disturbances of glucose-lipid metabolism as well as in obesity and fertility. Taking into consideration the ubiquity of PCOS in the human population, it seems indispensable to search for new potential therapeutic targets for this condition.

The aim of this review is to examine the relationship between metabolic disturbances and obesity in PCOS pathology. We discuss current and future therapeutic interventions for PCOS and related disorders, with emphasis on the metabolic pathways related to PCOS pathophysiology. The link between the ECS and PPARs is a promising new target for PCOS, and we examine this relationship in depth.”

https://pubmed.ncbi.nlm.nih.gov/36010645/

“There is a great potential to use CBs and their metabolites and non-cannabinoid dual CBRs/PPAR agonists as novel interventions for PCOS and related disorders. PCOS pathophysiology is complex and poorly understood. We demonstrate that the ECS and PPARs play an important role in the pathogenesis of PCOS (including mtCB1R). The complexity of the ECS and the PPARs will allow the development of diverse therapeutic modalities targeting these interrelated systems. Further, these interventions can be used to develop personalized approaches to treatment based on individual patient characteristics.”

https://www.mdpi.com/2073-4409/11/16/2569/htm