Enhanced endocannabinoid tone as a potential target of pharmacotherapy.

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“The endocannabinoid system is up-regulated in numerous pathophysiological states such as inflammatory, neurodegenerative, gastrointestinal, metabolic and cardiovascular diseases, pain, and cancer. It has been suggested that this phenomenon primarily serves an autoprotective role in inhibiting disease progression and/or diminishing signs and symptoms.

Accordingly, enhancement of endogenous endocannabinoid tone by inhibition of endocannabinoid degradation represents a promising therapeutic approach for the treatment of many diseases. Importantly, this allows for the avoidance of unwanted psychotropic side effects that accompany exogenously administered cannabinoids.

The effects of endocannabinoid metabolic pathway modulation are complex, as endocannabinoids can exert their actions directly or via numerous metabolites. The two main strategies for blocking endocannabinoid degradation are inhibition of endocannabinoid-degrading enzymes and inhibition of endocannabinoid cellular uptake.

To date, the most investigated compounds are inhibitors of fatty acid amide hydrolase (FAAH), an enzyme that degrades the endocannabinoid anandamide. However, application of FAAH inhibitors (and consequently other endocannabinoid degradation inhibitors) in medicine became questionable due to a lack of therapeutic efficacy in clinical trials and serious adverse effects evoked by one specific compound.

In this paper, we discuss multiple pathways of endocannabinoid metabolism, changes in endocannabinoid levels across numerous human diseases and corresponding experimental models, pharmacological strategies for enhancing endocannabinoid tone and potential therapeutic applications including multi-target drugs with additional targets outside of the endocannabinoid system (cyclooxygenase-2, cholinesterase, TRPV1, and PGF-EA receptors), and currently used medicines or medicinal herbs that additionally enhance endocannabinoid levels.

Ultimately, further clinical and preclinical studies are warranted to develop medicines for enhancing endocannabinoid tone.”

https://www.ncbi.nlm.nih.gov/pubmed/29729263

https://www.sciencedirect.com/science/article/pii/S0024320518302352

Molecular and cellular basis of cannabinoid and opioid interactions.

 Pharmacology Biochemistry and Behavior

“Cannabinoids and opioids have been shown to possess several similar pharmacological effects, including analgesia and stimulation of brain circuitry that are believed to underlie drug addiction and reward. In recent years, these phenomena have supported the possible existence of functional links in the mechanisms of action of both types of drugs.

The present review addresses the recent advances in the study of biochemical and molecular mechanisms underlying opioid and cannabinoid interaction. Several hypothesis have been formulated to explain this cross-modulation including the release of opioid peptides by cannabinoids or endocannabinoids by opioids and interaction at the level of receptor and/or their signal transduction mechanisms.

Moreover it is important to consider that the nature of cannabinoid and opioid interaction might differ in the brain circuits mediating reward and in those mediating other pharmacological properties, such as antinociception.

Further studies are needed since a better knowledge of the opioid-cannabinoid interaction may lead to exciting therapeutic possibilities.”

https://www.ncbi.nlm.nih.gov/pubmed/15927245

https://www.sciencedirect.com/science/article/pii/S0091305705001450?via%3Dihub

Synergistic interactions of endogenous opioids and cannabinoid systems.

 Brain Research

“Cannabinoids and opioids are distinct drug classes historically used in combination to treat pain. Delta(9)-THC, an active constituent in marijuana, releases endogenous dynorphin A and leucine enkephalin in the production of analgesia.

The endocannabinoid, anandamide (AEA), fails to release dynorphin A. The synthetic cannabinoid, CP55,940, releases dynorphin B. Neither AEA nor CP55,940 enhances morphine analgesia. The CB1 antagonist, SR141716A, differentially blocks Delta(9)-THC versus AEA. Tolerance to Delta(9)-THC, but not AEA, involves a decrease in the release of dynorphin A.

Our preclinical studies indicate that Delta(9)-THC and morphine can be useful in low dose combination as an analgesic. Such is not observed with AEA or CP55,940.

We hypothesize the existence of a new CB receptor differentially linked to endogenous opioid systems based upon data showing the stereoselectivity of endogenous opioid release. Such a receptor, due to the release of endogenous opioids, may have significant impact upon the clinical development of cannabinoid/opioid combinations for the treatment of a variety of types of pain in humans.”

https://www.ncbi.nlm.nih.gov/pubmed/10612710

https://www.sciencedirect.com/science/article/pii/S0006899399019083?via%3Dihub

The role of cannabinoid signaling in acute and chronic kidney diseases.

 Image result for Kidney Int. “The endogenous cannabinoids anandamide and 2-arachidonoylglycerol bind to the cannabinoid receptors of type 1 and 2. These receptors are also the binding sites for exogenous, both natural and synthetic, cannabinoids that are used for recreation purposes.

Until recently, cannabinoids and cannabinoid receptors have attracted little interest among nephrologists; however, a full endocannabinoid system (ECS) is present in the kidney and it has recently emerged as an important player in the pathogenesis of diabetic nephropathy, drug nephrotoxicity, and progressive chronic kidney disease.

This newly established role of the ECS in the kidney might have therapeutic relevance, as pharmacological modulation of the ECS has renoprotective effects in experimental animals, raising hope for future potential applications in humans.

In addition, over the last years, there has been a number of reported cases of acute kidney injury (AKI) associated with the use of synthetic cannabinoids that appear to have higher potency and rate of toxicity than natural Cannabis. This poorly recognized cause of renal injury should be considered in the differential diagnosis of AKI, particularly in young people.

In this review we provide an overview of preclinical evidence indicating a role of the ECS in renal disease and discuss potential future therapeutic applications.”

https://www.ncbi.nlm.nih.gov/pubmed/29706358

Adolescent chronic mild stress alters hippocampal CB1 receptor-mediated excitatory neurotransmission and plasticity

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“Endocannabinoids (eCBS) are involved in the stress response and alterations in eCB signaling may contribute to the etiology of mood disorders.

Exposure to chronic mild stress (CMS), a model of depression, produces downregulation of the CB1 receptor (CB1) in the hippocampus of male rats.

These results effectively demonstrate that CMS significantly alters hippocampal eCB-mediated neurotransmission and synaptic plasticity.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3827785/

Deficiency in endocannabinoid signaling in the nucleus accumbens induced by chronic unpredictable stress.

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“The nucleus accumbens (NAc) is a critical component of the reward circuitry, and dysfunction of the NAc may account for anhedonia and other symptoms of depression.

The endocannabinoid (eCB) system regulates mood, emotion, motivation, appetite, body weight, and cognition.

Here, we investigated whether alterations in endocannabinoid (eCB) signaling in the NAc contribute to depression-like behaviors induced by chronic unpredictable stress (CUS) in mice.

These results suggest that downregulation of eCB signaling in the NAc occurs after CUS and contributes to the pathophysiology of depression.”

Cannabidiol inhibits endocannabinoid signaling in autaptic hippocampal neurons.

Molecular Pharmacology

“Δ9-THC and cannabidiol (CBD) are two main cannabinoid constituents of marijuana and hashish. The pharmacology of Δ9-THC has been extensively studied, while our understanding of the pharmacology of CBD has remained limited, despite excitement in CBD’s potential role in treating certain pediatric epilepsies and its reputation for attenuating some Δ9-THC-induced effects.

It was established early on that CBD binds poorly to the orthosteric site of CB1 or CB2 cannabinoid receptors and its actions were commonly attributed to other non-cannabinoid receptor mechanisms. However, recent evidence suggests that CBD does indeed act at cannabinoid CB1 receptors as a negative allosteric modulator (NAM) of CB1 signaling. By altering the orthosteric signaling of a GPCR, allosteric modulators greatly increase the richness of GPCR pharmacology.

We have recently surveyed candidate CB1 NAMs in autaptic hippocampal neurons, a well-characterized neuronal model of endogenous cannabinoid signaling, and have now tested CBD in this model. We find that while CBD has no direct effect on excitatory transmission it does inhibit two forms of endogenous cannabinoid-mediated retrograde synaptic plasticity: depolarization-induced suppression of excitation (DSE) and metabotropic suppression of excitation (MSE), while not affecting signaling via GABA-B receptors.

These results are consistent with the recently described NAM activity of CBD and suggest interesting possible mechanisms for CBD’s therapeutic actions.”

Endocannabinoid system in systemic lupus erythematosus: first evidence for a deranged 2-arachidonoylglycerol metabolism.

The International Journal of Biochemistry & Cell Biology

“The endocannabinoid (eCB) system plays a key role in many physiological and pathological conditions and its dysregulation has been described in several rheumatological and autoimmune diseases. Yet, its possible alteration in systemic lupus erythematosus (SLE) has never been investigated.

Here, we aimed filling this gap in plasma and peripheral blood mononuclear cells (PBMCs) of patients with SLE and age- and sex- matched healthy subjects (HS).

In conclusion, our results demonstrate, for the first time, an alteration of eCB system in SLE patients. They represents the first step toward the understanding of the role of eCB system in SLE that likely suggest DAGL and 2-AG as potential biomarkers of SLE in easily accessible blood samples.

Our data provides proof-of-concept to the development of cannabis-based medicine as immune-modulating agents.”

https://www.ncbi.nlm.nih.gov/pubmed/29655919

Therapeutic cannabinoids in multiple sclerosis: immunomodulation revisited.

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Cannabinoids are compounds with pleiotropic properties that act on the cannabinoid receptors, CB1 and CB2, and are divided into endocannabinoids, the endogenous ligands of these receptors, synthetic cannabinoids and phytocannabinoids.

The latter are derived from the plant Cannabis sativa. The therapeutic and psychoactive properties of this plant have been observed and used for centuries.

Of the over 60 compounds that are unique to Cannabis sativa, the substances that have been attributed the greatest therapeutic potential are Δ9 – tetrahydrocannabinol (THC) and cannabidiol (CBD), both of which, used alone or combined with each other, have become approved drugs.”

https://www.ncbi.nlm.nih.gov/pubmed/29633480

https://onlinelibrary.wiley.com/doi/abs/10.1111/ene.13658

Endocannabinoid System and Migraine Pain: An Update.

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“The trigeminovascular system (TS) activation and the vasoactive release from trigeminal endings, in proximity of the meningeal vessels, are considered two of the main effector mechanisms of migraine attacks. Several other structures and mediators are involved, however, both upstream and alongside the TS.

Among these, the endocannabinoid system (ES) has recently attracted considerable attention. Experimental and clinical data suggest indeed a link between dysregulation of this signaling complex and migraine headache.

Clinical observations, in particular, show that the levels of anandamide (AEA)-one of the two primary endocannabinoid lipids-are reduced in cerebrospinal fluid and plasma of patients with chronic migraine (CM), and that this reduction is associated with pain facilitation in the spinal cord.

AEA is produced on demand during inflammatory conditions and exerts most of its effects by acting on cannabinoid (CB) receptors. AEA is rapidly degraded by fatty acid amide hydrolase (FAAH) enzyme and its levels can be modulated in the peripheral and central nervous system (CNS) by FAAH inhibitors.

Inhibition of AEA degradation via FAAH is a promising therapeutic target for migraine pain, since it is presumably associated to an increased availability of the endocannabinoid, specifically at the site where its formation is stimulated (e.g., trigeminal ganglion and/or meninges), thus prolonging its action.”

https://www.ncbi.nlm.nih.gov/pubmed/29615860

https://www.frontiersin.org/articles/10.3389/fnins.2018.00172/full