Tag Archives: endocannabinoid system

High Times for Painful Blues: The Endocannabinoid System in Pain-Depression Comorbidity.

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“Depression and pain are two of the most debilitating disorders worldwide and have an estimated cooccurrence of up to 80%. Comorbidity of these disorders is more difficult to treat, associated with significant disability and impaired health-related quality of life than either condition alone, resulting in enormous social and economic cost.

Several neural substrates have been identified as potential mediators in the association between depression and pain, including neuroanatomical reorganization, monoamine and neurotrophin depletion, dysregulation of the hypothalamo-pituitary-adrenal axis, and neuroinflammation.

However, the past decade has seen mounting evidence supporting a role for the endogenous cannabinoid (endocannabinoid) system in affective and nociceptive processing, and thus, alterations in this system may play a key role in reciprocal interactions between depression and pain.

This review will provide an overview of the preclinical evidence supporting an interaction between depression and pain and the evidence supporting a role for the endocannabinoid system in this interaction.”

http://www.ncbi.nlm.nih.gov/pubmed/26342110

“The plant Cannabis sativa has been used as a medicine throughout the world for several thousand years, with reports of its use in treating painful symptoms appearing as early as 2600 BC. The principal psychoactive ingredient of Cannabis sativa, delta-9-tetrahydrocannabinol (Δ9-THC), was first identified in 1964, and subsequent studies to understand its mechanism of action led to the discovery of the endogenous cannabinoid (endocannabinoid) system… Because of the distribution of the endocannabinoid system throughout spinal and supraspinal regions, it is in a prime position to regulate neurophysiological activities such as affective and nociceptive processing… evidence suggests a prominent role for the endocannabinoid system in the interaction between depression and pain,” http://ijnp.oxfordjournals.org/content/early/2015/09/04/ijnp.pyv095.long

G protein-coupled receptor 18: A potential role for endocannabinoid signalling in metabolic dysfunction.

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“Endocannabinoids are products of dietary fatty acids that are modulated by an alteration in food intake levels.

Overweight and obese individuals have substantially higher circulating levels of the arachidonic acid-derived endocannabinoids, anandamide and 2-arachidonoyl glycerol, and show an altered pattern of cannabinoid receptor expression.

These cannabinoid receptors are part of a large family of G protein-coupled receptors (GPCRs).

GPCRs are major therapeutic targets for various diseases within the cardiovascular, neurological, gastrointestinal and endocrine systems, as well as metabolic disorders such as obesity and type 2 diabetes mellitus.

Obesity is considered a state of chronic low grade inflammation elicited by an immunological response.

Interestingly, the newly deorphanised G protein-coupled receptor GPR18, which is considered to be a putative cannabinoid receptor, is proposed to have an immunological function.

In this review, the current scientific knowledge on GPR18 is explored including its localisation, signalling pathways and pharmacology.

Importantly, the involvement of nutritional factors and potential dietary regulation of GPR18 and its (patho)physiological roles are described.

Further research on this receptor and its regulation will enable a better understanding of the complex mechanisms of GPR18 and its potential as a novel therapeutic target for treating metabolic disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26337420

Fatty acids, endocannabinoids and inflammation.

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“From their phylogenetic and pharmacological classification it might be inferred that cannabinoid receptors and their endogenous ligands constitute a rather specialised and biologically distinct signalling system.

However, the opposite is true and accumulating data underline how much the endocannabinoid system is intertwined with other lipid and non-lipid signalling systems.

Endocannabinoids per se have many structural congeners, and these molecules exist in dynamic equilibria with different other lipid-derived mediators, including eicosanoids and prostamides.

With multiple crossroads and shared targets, this creates a versatile system involved in fine-tuning different physiological and metabolic processes, including inflammation.

A key feature of this ‘expanded’ endocannabinoid system, or ‘endocannabinoidome’, is its subtle orchestration based on interactions between a relatively small number of receptors and multiple ligands with different but partly overlapping activities.

Following an update on the role of the ‘endocannabinoidome’ in inflammatory processes, this review continues with possible targets for intervention at the level of receptors or enzymes involved in formation or breakdown of endocannabinoids and their congeners.

Although its pleiotropic character poses scientific challenges, the ‘expanded’ endocannabinoid system offers several opportunities for prevention and therapy of chronic diseases.

In this respect, successes are more likely to come from ‘multiple-target’ than from ‘single-target’ strategies.”

http://www.ncbi.nlm.nih.gov/pubmed/26325095

Endocannabinoid System Contributes to Liver Injury and Inflammation by Activation of Bone Marrow-Derived Monocytes/Macrophages in a CB1-Dependent Manner.

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“Hepatic injury undergoes significant increases in endocannabinoids and infiltrations of macrophages, yet the concrete mechanisms of changes in endocannabinoids and the functions of macrophage-expressed cannabinoid receptors (CBs) are unclear…

In the chimeric murine model, we found that blockade of CB1 by administration of a CB1 antagonist inhibited the recruitment of Bone marrow-derived monocytes/macrophages (BMM) into injured liver using immunofluorescence staining and FACS, but it did not have effects on migration of T cells and dendritic cells without CB1 expression. Furthermore, activation of CB1 enhanced cytokine expression of BMM. In vivo, inhibition of CB1 attenuated the inflammatory cytokine level through real-time RT-PCR and cytometric bead array, ameliorating hepatic inflammation and fibrosis.

In this study, we identify inactivation of BMM-expressed CB1 as a therapeutic strategy for reducing hepatic inflammation and fibrosis.”

http://www.ncbi.nlm.nih.gov/pubmed/26320250

Increasing levels of the endocannabinoid 2-AG is neuroprotective in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson’s disease.

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“Parkinson’s disease (PD) is a common chronic neurodegenerative disorder, usually of idiopathic origin. Symptoms including tremor, bradykinesia, rigidity and postural instability are caused by the progressive loss of dopaminergic neurons in the nigrostriatal region of the brain.

Symptomatic therapies are available but no treatment slows or prevents the loss of neurons.

Neuroinflammation has been implicated in its pathogenesis.

To this end, the present study utilises the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin to reproduce the pattern of cell death evident in PD patients.

Herein, the role of a potential regulator of an immune response, the endocannabinoid system (ECS), is investigated.

The most prevalent endocannabinoid, 2-arachidonoylglycerol (2-AG) (3 and 5mg/kg), was added exogenously and its enzymatic degradation inhibited to provide protection against MPTP-induced cell death.

Furthermore, the addition of DFU (25mg/kg), a selective inhibitor of inflammatory mediator cyclooxygenase-2 (COX-2), potentiated these effects.

Levels of 2-AG were shown to be upregulated in a time- and region-specific manner following MPTP administration, indicating that the ECS represents a natural defence mechanism against inflammation, potentiation of which could provide therapeutic benefits.

The results expand the current understanding of the role that this signalling system has and its potential influence in PD.”

Age-related changes in the endocannabinoid system in the mouse hippocampus.

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“Previous studies have demonstrated that the endocannabinoid system significantly influences the progression of brain ageing, and the hippocampus is one of the brain regions most vulnerable to ageing and neurodegeneration.

We have further examined age-related changes in the hippocampalendocannabinoid system by measuring the levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in young and old mice from two different mouse strains.

We found a decrease in 2-AG but not AEA levels in aged mice.

In order to identify the cause for 2-AG level changes, we investigated the levels of several enzymes that contribute to synthesis and degradation of 2-AG in the hippocampus.

We found a selective decrease in DAGLα mRNA and protein levels as well as an elevated MAGL activity during ageing.

We hypothesize that the observed decrease of 2-AG levels is probably caused by changes in DAGLα expression and MAGL activity.

This finding can contribute to the existing knowledge about the processes underlying selective vulnerability of the hippocampus to ageing and age-related neurodegeneration.”

http://www.ncbi.nlm.nih.gov/pubmed/26278494

Effect of anandamide on endometrial adenocarcinoma (Ishikawa) cell numbers: implications for endometrial cancer therapy.

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“We have previously shown that patients with endometrial carcinoma express elevated concentrations of the endocannabinoid, anandamide (AEA), in both their plasma and their endometrial tissue and that the endometrial carcinoma cell line, Ishikawa, contains the receptors to which AEA binds.

Several studies have reported that human and rodent cancer cell lines die in response to high AEA concentrations.

The incidence of endometrial carcinoma continues to escalate and, although surgical treatment has improved, morbidity and mortality rates have not. A move towards a novel non-surgical therapeutic option is thus required, and the endocannabinoid system provides a good candidate target.

We aimed to investigate the effects of AEA on the survival and proliferation of an endometrial carcinoma cell model.

Our results show that AEA induces a decrease in Ishikawa cell number probably through inhibition of cell proliferation rather than cell death.

These data suggest that the increased plasma and tissue AEA concentrations observed in patients with endometrial cancer is a counter mechanism against further cancer growth and points to the endocannabinoid system as a potentially new therapeutic target.”

http://www.ncbi.nlm.nih.gov/pubmed/26312842

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(15)60335-X/fulltext

Cannabinoids and Schizophrenia: Risks and Therapeutic Potential.

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“The endocannabinoid system has been implicated in psychosis both related and unrelated to cannabis exposure, and studying this system holds potential to increase understanding of the pathophysiology of schizophrenia.

Anandamide signaling in the central nervous system may be particularly important.

Δ9-Tetrahydrocannabinol in cannabis can cause symptoms of schizophrenia when acutely administered, and cannabidiol (CBD), another compound in cannabis, can counter many of these effects.

CBD may have therapeutic potential for the treatment of psychosis following cannabis use, as well as schizophrenia, possibly with better tolerability than current antipsychotic treatments. CBD may also have anti-inflammatory and neuroprotective properties.

Establishing the role of CBD and other CBD-based compounds in treating psychotic disorders will require further human research.”

http://www.ncbi.nlm.nih.gov/pubmed/26311150

http://www.thctotalhealthcare.com/category/schizophrenia/

Pro-inflammatory obesity in aged cannabinoid-2 receptor deficient mice.

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“Cannabinoid-1 receptor signaling increases the rewarding effects of food intake and promotes the growth of adipocytes, whereas CB2 possibly opposes these pro-obesity effects by silencing the activated immune cells that are key drivers of the metabolic syndrome.

Pro- and anti-orexigenic cannabimimetic signaling may become unbalanced with age because of alterations of the immune and endocannabinoid system…

CB2 agonists may fortify CB2-mediated anti-obesity signaling without the risk of anti-CB1 mediated depression that caused the failure of rimonabant.”

http://www.ncbi.nlm.nih.gov/pubmed/26303348

[Neuroprotective mechanisms of cannabinoids in brain ischemia and neurodegenerative disorders].

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“One of the most important causes of morbidity and mortality is neurologic dysfunction; its high incidence has led to an intense research of the mechanisms that protect the central nervous system from hypoxia and ischemia. The mayor challenge is to block the biochemical events leading to neuronal death.

This may be achieved by neuroprotective mechanisms that avoid the metabolic and immunologic cascades that follow a neurological damage. When it occurs, several pathophysiological events develop including cytokine release, oxidative stress and excitotoxicity.

Neuroprotective effects of cannabinoids to all those mechanisms have been reported in animal models of brain ischemia, excitotoxicity, brain trauma and neurodegenerative disorders.

Some endocannabinoid analogs are being tested in clinical studies (I-III phase) for acute disorders involving neuronal death (brain trauma and ischemia).

The study of the cannabinoid system may allow the discovery of effective neuroprotective drugs for the treatment of neurological disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26299059