Category Archives: Endocannabinoid System

Turning Down the Thermostat: Modulating the Endocannabinoid System in Ocular Inflammation and Pain.

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“The endocannabinoid system (ECS) has emerged as an important regulator of both physiological and pathological processes. Notably, this endogenous system plays a key role in the modulation of pain and inflammation in a number of tissues.

The components of the ECS, including endocannabinoids, their cognate enzymes and cannabinoid receptors, are localized in the eye, and evidence indicates that ECS modulation plays a role in ocular disease states.

Of these diseases, ocular inflammation presents a significant medical problem, given that current clinical treatments can be ineffective or are associated with intolerable side-effects. Furthermore, a prominent comorbidity of ocular inflammation is pain, including neuropathic pain, for which therapeutic options remain limited.

Recent evidence supports the use of drugs targeting the ECS for the treatment of ocular inflammation and pain in animal models; however, the potential for therapeutic use of cannabinoid drugs in the eye has not been thoroughly investigated at this time.

This review will highlight evidence from experimental studies identifying components of the ocular ECS and discuss the functional role of the ECS during different ocular inflammatory disease states, including uveitis and corneal keratitis.

Candidate ECS targeted therapies will be discussed, drawing on experimental results obtained from both ocular and non-ocular tissue(s), together with their potential application for the treatment of ocular inflammation and pain.”

https://www.ncbi.nlm.nih.gov/pubmed/27695415

β-caryophyllene and β-caryophyllene oxide-natural compounds of anticancer and analgesic properties.

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Cancer Biology & Medicine

“Natural bicyclic sesquiterpenes, β-caryophyllene (BCP) and β-caryophyllene oxide (BCPO), are present in a large number of plants worldwide.

Both BCP and BCPO (BCP(O)) possess significant anticancer activities, affecting growth and proliferation of numerous cancer cells.

In addition, both compounds potentiate the classical drug efficacy by augmenting their concentrations inside the cells.

BCP is a phytocannabinoid with strong affinity to cannabinoid receptor type 2 (CB2 ), but not cannabinoid receptor type 1 (CB1 ). In opposite, BCP oxidation derivative, BCPO, does not exhibit CB1/2 binding, thus the mechanism of its action is not related to endocannabinoid system (ECS) machinery.

It is known that BCPO alters several key pathways for cancer development, such as mitogen-activated protein kinase (MAPK), PI3K/AKT/mTOR/S6K1 and STAT3 pathways. In addition, treatment with this compound reduces the expression of procancer genes/proteins, while increases the levels of those with proapoptotic properties.

The selective activation of CB2 may be considered a novel strategy in pain treatment, devoid of psychoactive side effects associated with CB1 stimulation. Thus, BCP as selective CB2 activator may be taken into account as potential natural analgesic drug.

Moreover, due to the fact that chronic pain is often an element of cancer disease, the double activity of BCP, anticancer and analgesic, as well as its beneficial influence on the efficacy of classical chemotherapeutics, is particularly valuable in oncology.

This review is focused on anticancer and analgesic activities of BCP and BCPO, the mechanisms of their actions, and potential therapeutic utility.”

https://www.ncbi.nlm.nih.gov/pubmed/27696789

“β-caryophyllene (BCP) is a common constitute of the essential oils of numerous spice, food plants and major component in Cannabis.”  http://www.ncbi.nlm.nih.gov/pubmed/23138934

Anandamide Suppresses Proinflammatory T Cell Responses In Vitro through Type-1 Cannabinoid Receptor-Mediated mTOR Inhibition in Human Keratinocytes.

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“The endocannabinoid system comprises cannabinoid receptors 1 and 2 (CB1 and CB2), their endogenous ligands, anandamide (AEA) and 2-arachidonoylglycerol, and metabolic enzymes of these ligands.

The endocannabinoid system has recently been implicated in the regulation of various pathophysiological processes of the skin that include immune competence and/or tolerance of keratinocytes, the disruption of which might promote the development of skin diseases.

Recent evidence showed that CB1 in keratinocytes limits the secretion of proinflammatory chemokines, suggesting that this receptor might also regulate T cell dependent inflammatory diseases of the skin.

In this article, we sought to investigate the cytokine profile of IFN-γ-activated keratinocytes, and found that CB1 activation by AEA suppressed production and release of signature TH1- and TH17-polarizing cytokines, IL-12 and IL-23, respectively. We also set up cocultures between a conditioned medium of treated keratinocytes and naive T cells to disclose the molecular details that regulate the activation of highly proinflammatory TH1 and TH17 cells.

AEA-treated keratinocytes showed reduced an induction of IFN-γ-producing TH1 and IL-17-producing TH17 cells, and these effects were reverted by pharmacological inhibition of CB1.

Further analyses identified mammalian target of rapamycin as a proinflammatory signaling pathway regulated by CB1, able to promote either IL-12 and IL-23 release from keratinocytes or TH1 and TH17 polarization.

Taken together, these findings demonstrate that AEA suppresses highly pathogenic T cell subsets through CB1-mediated mammalian target of rapamycin inhibition in human keratinocytes.

Thus, it can be speculated that the latter pathway might be beneficial to the physiological function of the skin, and can be targeted toward inflammation-related skin diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/27694494

Targeting Cannabinoid CB2 Receptors in the Central Nervous System. Medicinal Chemistry Approaches with Focus on Neurodegenerative Disorders.

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“Endocannabinoids activate two types of specific G-protein-coupled receptors (GPCRs), namely cannabinoid CB1 and CB2. Contrary to the psychotropic actions of agonists of CB1 receptors, and serious side effects of the selective antagonists of this receptor, drugs acting on CB2 receptors appear as promising drugs to combat CNS diseases (Parkinson’s disease, Huntington’s chorea, cerebellar ataxia, amyotrohic lateral sclerosis). Differential localization of CB2 receptors in neural cell types and upregulation in neuroinflammation are keys to understand the therapeutic potential in inter alia diseases that imply progressive neurodegeneration. Medicinal chemistry approaches are now engaged to develop imaging tools to map receptors in the living human brain, to develop more efficacious agonists, and to investigate the possibility to develop allosteric modulators.”

 https://www.ncbi.nlm.nih.gov/pubmed/27679556

THC (Δ9-Tetrahydrocannabinol) Exerts Neuroprotective Effect in Glutamate-affected Murine Primary Mesencephalic Cultures Through Restoring Mitochondrial Membrane Potential and Anti-apoptosis Involving CB1 Receptor-dependent Mechanism.

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Phytotherapy Research

“Aging-related neurodegenerative diseases, such as Parkinson’s disease (PD) or related disorders, are an increasing societal and economic burden worldwide.

Δ9-Tetrahydrocannabinol (THC) is discussed as a neuroprotective agent in several in vitro and in vivo models of brain injury. However, the mechanisms by which THC exhibits neuroprotective properties are not completely understood.

In the present study, we investigated neuroprotective mechanisms of THC in glutamate-induced neurotoxicity in primary murine mesencephalic cultures, as a culture model for PD.

THC protected dopaminergic neurons and other cell types of primary dissociated cultures from glutamate-induced neurotoxicity.

Moreover, THC significantly counteracted the glutamate-induced mitochondrial membrane depolarization and apoptosis.

In conclusion, THC exerts anti-apoptotic and restores mitochondrial membrane potential via a mechanism dependent on CB1 receptor.

It strengthens the fact that THC has a benefit on degenerative cellular processes occurring, among others, in PD and other neurodegenerative diseases by slowing down the progression of neuronal cell death.”

https://www.ncbi.nlm.nih.gov/pubmed/27654887

http://onlinelibrary.wiley.com/wol1/doi/10.1002/ptr.5712/full

Targeting anandamide metabolism rescues core and associated autistic-like symptoms in rats prenatally exposed to valproic acid.

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“Autism spectrum disorders (ASD) are characterized by altered sociability, compromised communication and stereotyped/repetitive behaviors, for which no specific treatments are currently available. Prenatal exposure to valproic acid (VPA) is a known, although still underestimated, environmental risk factor for ASD.

Altered endocannabinoid activity has been observed in autistic patients, and endocannabinoids are known to modulate behavioral traits that are typically affected in ASD. On this basis, we tested the hypothesis that changes in the endocannabinoid tone contribute to the altered phenotype induced by prenatal VPA exposure in rats, with focus on behavioral features that resemble the core and associated symptoms of ASD.

In the course of development, VPA-exposed rats showed early deficits in social communication and discrimination, compromised sociability and social play behavior, stereotypies and increased anxiety, thus providing preclinical proof of the long-lasting deleterious effects induced by prenatal VPA exposure. At the neurochemical level, VPA-exposed rats displayed altered phosphorylation of CB1 cannabinoidreceptors in different brain areas, associated with changes in anandamide metabolism from infancy to adulthood.

Interestingly, enhancing anandamide signaling through inhibition of its degradation rescued the behavioral deficits displayed by VPA-exposed rats at infancy, adolescence and adulthood.

This study therefore shows that abnormalities in anandamide activity may underlie the deleterious impact of environmental risk factors on ASD-relevant behaviors and that the endocannabinoid system may represent a therapeutic target for the core and associated symptoms displayed by autistic patients.”

 https://www.ncbi.nlm.nih.gov/pubmed/27676443

Tetrahydropyrazolo[4,3-c]pyridine derivatives as potent and peripherally selective cannabinoid-1 (CB1) receptor inverse agonists.

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“Peripherally restricted CB1 receptor inverse agonists hold potential as useful therapeutics to treat obesity and related metabolic diseases without causing undesired CNS-mediated adverse effects. We identified a series of tetrahydropyrazolo[4,3-c]pyridine derivatives as potent and highly peripherally selective CB1 receptor inverse agonists. This discovery was achieved by introducing polar functional groups into the molecule, which increase the topological polar surface area and reduce its brain-penetrating ability.”

https://www.ncbi.nlm.nih.gov/pubmed/27671499

“Tetrahydroindazole derivatives as potent and peripherally selective cannabinoid-1 (CB1) receptor inverse agonists. A series of potent and receptor-selective cannabinoid-1 (CB1) receptor inverse agonists has been discovered. Peripheral selectivity of the compounds was assessed by a mouse tissue distribution study, in which the concentrations of a test compound in both plasma and brain were measured. A number of peripherally selective compounds have been identified through this process. Compound 2p was further evaluated in a 3-week efficacy study in the diet-induced obesity (DIO) mouse model. Beneficial effects on plasma glucose were observed from the compound-treated mice.”  https://www.ncbi.nlm.nih.gov/pubmed/27671496

The Effect of Chronic Activation of the Novel Endocannabinoid Receptor GPR18 on Myocardial Function and Blood Pressure in Conscious Rats.

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“While acute activation of the novel endocannabinoid receptor GPR18 causes hypotension, there are no reports on GPR18 expression in the heart or its chronic modulation of cardiovascular function. In this study, after demonstrating GPR18 expression in the heart, we show that chronic (2 weeks) GPR18 activation with its agonist abnormal cannabidiol (abn-cbd; 100 µg/kg/day; i.p) produced hypotension, suppressed the cardiac sympathetic dominance, and improved left ventricular (LV) function (increased the contractility index dp/dtmax, and reduced LV end diastolic pressure, LVEDP) in conscious rats. Ex vivo studies revealed increased: (i) cardiac and plasma adiponectin (ADN) levels; (ii) vascular (aortic) endothelial nitric oxide synthase (eNOS) expression, (iii) vascular and serum nitric oxide (NO) levels; (iv) myocardial and plasma cyclic guanosine monophosphate (cGMP) levels; (v) phosphorylation of myocardial protein kinase B (Akt) and extracellular signal regulated kinase 1/2 (ERK1/2) along with reduced myocardial reactive oxygen species (ROS) in abn-cbd treated rats. These biochemical responses contributed to the hemodynamic responses and were GPR18-mediated because concurrent treatment with the competitive GPR18 antagonist (O-1918) abrogated the abn-cbd evoked hemodynamic and biochemical responses. The current findings present new evidence for a salutary cardiovascular role for GPR18, mediated, at least partly, via elevation in the levels of ADN.”

 https://www.ncbi.nlm.nih.gov/pubmed/27676325

Endocannabinoid signaling in social functioning: an RDoC perspective.

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“Core deficits in social functioning are associated with various neuropsychiatric and neurodevelopmental disorders, yet biomarker identification and the development of effective pharmacological interventions has been limited.

Recent data suggest the intriguing possibility that endogenous cannabinoids, a class of lipid neuromodulators generally implicated in the regulation of neurotransmitter release, may contribute to species-typical social functioning.

Systematic study of the endogenous cannabinoid signaling could, therefore, yield novel approaches to understand the neurobiological underpinnings of atypical social functioning.

This article provides a critical review of the major components of the endogenous cannabinoid system (for example, primary receptors and effectors-Δ9-tetrahydrocannabinol, cannabidiol, anandamide and 2-arachidonoylglycerol) and the contributions of cannabinoid signaling to social functioning.

Data are evaluated in the context of Research Domain Criteria constructs (for example, anxiety, chronic stress, reward learning, motivation, declarative and working memory, affiliation and attachment, and social communication) to enable interrogation of endogenous cannabinoid signaling in social functioning across diagnostic categories.

The empirical evidence reviewed strongly supports the role for dysregulated cannabinoid signaling in the pathophysiology of social functioning deficits observed in brain disorders, such as autism spectrum disorder, schizophrenia, major depressive disorder, posttraumatic stress disorder and bipolar disorder.

Moreover, these findings indicate that the endogenous cannabinoid system holds exceptional promise as a biological marker of, and potential treatment target for, neuropsychiatric and neurodevelopmental disorders characterized by impairments in social functioning.”

https://www.ncbi.nlm.nih.gov/pubmed/27676446

Cannabidiol, among Other Cannabinoid Drugs, Modulates Prepulse Inhibition of Startle in the SHR Animal Model: Implications for Schizophrenia Pharmacotherapy.

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“Schizophrenia is a severe psychiatric disorder that involves positive, negative and cognitive symptoms. Prepulse inhibition of startle reflex (PPI) is a paradigm that assesses the sensorimotor gating functioning and is impaired in schizophrenia patients as well as in animal models of this disorder. Recent data point to the participation of the endocannabinoid system in the pathophysiology and pharmacotherapy of schizophrenia. Here, we focus on the effects of cannabinoid drugs on the PPI deficit of animal models of schizophrenia, with greater focus on the SHR (Spontaneously Hypertensive Rats) strain, and on the future prospects resulting from these findings.”

 https://www.ncbi.nlm.nih.gov/pubmed/27667973