Category Archives: Endocannabinoid System

Towards A Molecular Understanding of The Cannabinoid Related Orphan Receptor GPR18: A Focus on Its Constitutive Activity.

Posted on by
Reply

ijms-logo

“The orphan G-protein coupled receptor (GPCR), GPR18, has been recently proposed as a potential member of the cannabinoid family as it recognizes several endogenous, phytogenic, and synthetic cannabinoids. Potential therapeutic applications for GPR18 include intraocular pressure, metabolic disorders, and cancer. GPR18 has been reported to have high constitutive activity, i.e., activation/signaling occurs in the absence of an agonist. This activity can be reduced significantly by the A3.39N mutation. At the intracellular (IC) ends of (transmembrane helices) TMH3 and TMH6 in GPCRs, typically, a pair of oppositely charged amino acids form a salt bridge called the “ionic lock”. Breaking of this salt bridge creates an IC opening for coupling with G protein. The GPR18 “ionic lock” residues (R3.50/S6.33) can form only a hydrogen bond. In this paper, we test the hypothesis that the high constitutive activity of GPR18 is due to the weakness of its “ionic lock” and that the A3.39N mutation strengthens this lock. To this end, we report molecular dynamics simulations of wild-type (WT) GPR18 and the A3.39N mutant in fully hydrated (POPC) phophatidylcholine lipid bilayers. Results suggest that in the A3.39N mutant, TMH6 rotates and brings R3.50 and S6.33 closer together, thus strengthening the GPR18 “ionic lock”.”

https://www.ncbi.nlm.nih.gov/pubmed/31075933

https://www.mdpi.com/1422-0067/20/9/2300

Endocannabinoid System in Spinocerebellar Ataxia Type-3 and Other Autosomal-Dominant Cerebellar Ataxias: Potential Role in Pathogenesis and Expected Relevance as Neuroprotective Targets.

Posted on by
Reply
Image result for frontiers in molecular neuroscience
“Spinocerebellar ataxias (SCAs) are a group of hereditary and progressive neurological disorders characterized by a loss of balance and motor coordination. SCAs have no cure and effective symptom-alleviating and disease-modifying therapies are not currently available. However, based on results obtained in studies conducted in murine models and information derived from analyses in post-mortem tissue samples from patients, which show notably higher levels of CB1 receptors found in different cerebellar neuronal subpopulations, the blockade of these receptors has been proposed for acutely modulating motor incoordination in cerebellar ataxias, whereas their chronic activation has been proposed for preserving specific neuronal losses. Additional studies in post-mortem tissues from SCA patients have also demonstrated elevated levels of CB2 receptors in Purkinje neurons as well as in glial elements in the granular layer and in the cerebellar white matter, with a similar profile found for endocannabinoid hydrolyzing enzymes, then suggesting that activating CB2 receptors and/or inhibiting these enzymes may also serve to develop cannabinoid-based neuroprotective therapies.”
https://www.ncbi.nlm.nih.gov/pubmed/31068788
“Dysregulation of the endocannabinoid signaling system in the cerebellum and brainstem in a transgenic mouse model of spinocerebellar ataxia type-3.” https://www.ncbi.nlm.nih.gov/pubmed/27717809

Endocannabinoid contributions to alcohol habits and motivation: Relevance to treatment.

Posted on by
Reply

Addiction Biology banner“Individuals with alcohol use disorder exhibit compulsive habitual behaviors that are thought to be, in part, a consequence of chronic and persistent use of alcohol.

The endocannabinoid system plays a critical role in habit learning and in ethanol self-administration, but the role of this neuromodulatory system in the expression of habitual alcohol seeking is unknown.

Here, we investigated the role of the endocannabinoid system in established alcohol habits using contingency degradation in male C57BL/6 mice.

These results demonstrate an important role for endocannabinoid signaling in the motivation to seek ethanol, in ethanol-motivated habits, and suggest that pharmacological manipulations of endocannabinoid signaling could be effective therapeutics for treating alcohol use disorder.”

https://www.ncbi.nlm.nih.gov/pubmed/31056846

https://onlinelibrary.wiley.com/doi/abs/10.1111/adb.12768

Using Cannabis to Treat Cancer-Related Pain.

Posted on by
Reply

Seminars in Oncology Nursing

“OBJECTIVE: To describe which cannabinoids and terpenes are effective for treating pain.

CONCLUSION: Cannabis and cannabinoid medicines, as modulators of the endocannabinoid system, offer novel therapeutic options for the treatment of cancer-related pain, not only for patients who do not respond to conventional therapies, but also for patients who prefer to try cannabis as a first treatment option.

IMPLICATIONS FOR NURSING PRACTICE: Understanding the endocannabinoid system, cannabinoids, terpenes, routes of administration, potential drug interactions, clinical implications, and potential side effects ensures nurses can better assist patients who use cannabis for the treatment of cancer pain.”

https://www.ncbi.nlm.nih.gov/pubmed/31053395

https://www.sciencedirect.com/science/article/pii/S0749208119300609?via%3Dihub

Marijuana for Parkinson’s Disease?

Posted on by
Reply

 Image result for innov clin neurosci

“Marijuana is popular in the United States and is being widely legalized for recreational and medicinal purposes. It remains a Schedule 1 substance without fully proven risks and benefits; yet, it is increasingly available in many US states and territories.

Cannabis might have medicinal efficacy in Parkinson’s disease as a form of medical marijuana. Endocannabinoid receptors exist throughout the nervous system and are documented to influence receptors affecting a wide variety of areas. Neuroprotective aspects might be induced by cannabis exposure that might yield benefit against the nigrostriatal degeneration of patients with Parkinson’s disease.

Animal investigations support suggestions of improvement in bradykinesia and/or tremors, but this is unsubstantiated in human studies. However, some patient surveys and anecdotal or case reports indicate that marijuana attenuates some motor manifestations of parkinsonism and also of non-motor, mood and/or cognitive symptoms. Medical marijuana might benefit motor and nonmotor aspects of Parkinson’s disease patients. Currently, these assertions are not substantiated in human investigations and cannabis can also induce side effects. Until studies clarify the safety and efficacy of pharmacotherapy with cannabis products, medical marijuana remains largely without scientific endorsement. Research has yet to document the full benefits, risks, and clinical applications of marijuana as a treatment for patients with Parkinson’s disease.”

https://www.ncbi.nlm.nih.gov/pubmed/31037227

Emerging evidence for the antidepressant effect of cannabidiol and the underlying molecular mechanisms.

Posted on by
Reply

Journal of Chemical Neuroanatomy

“Significant limitations with the currently available antidepressant treatment strategies have inspired research on finding new and more efficient drugs to treat depression. Cannabidiol (CBD) is a non-psychotomimetic component of Cannabis sativa, and emerges in this regard as a promising compound. In 2010, we were the first laboratory to demonstrate that CBD is effective in animal models of predictive of antidepressant effect, a finding now confirmed by several other groups. Recent evidence suggests that CBD promotes both a rapid and a sustained antidepressant effect in animal models. CBD has a complex pharmacology, with the ability to interact with multiple neurotransmitter systems involved in depression, including the serotonergic, glutamatergic, and endocannabinoid systems. Moreover, CBD induces cellular and molecular changes in brain regions related to depression neurobiology, such as increased Brain Derived Neurotrophic Factor (BDNF) levels and synaptogenesis in the medial prefrontal cortex, as well as it increases neurogenesis in the hippocampus. This review presents a comprehensive critical overview of the current literature related to the antidepressant effects of CBD, with focus at the possible mechanisms. Finally, challenges and perspectives for future research are discussed.”

https://www.ncbi.nlm.nih.gov/pubmed/31039391

https://www.sciencedirect.com/science/article/pii/S0891061818302114?via%3Dihub

Role of Cannabinoid Receptor Type 1 in Insulin Resistance and Its Biological Implications.

Posted on by
Reply

ijms-logo “Endogenous cannabinoids (ECs) are lipid-signaling molecules that specifically bind to cannabinoid receptor types 1 and 2 (CB1R and CB2R) and are highly expressed in central and many peripheral tissues under pathological conditions. Activation of hepatic CB1R is associated with obesity, insulin resistance, and impaired metabolic function, owing to increased energy intake and storage, impaired glucose and lipid metabolism, and enhanced oxidative stress and inflammatory responses. Additionally, blocking peripheral CB1R improves insulin sensitivity and glucose metabolism and also reduces hepatic steatosis and body weight in obese mice. Thus, targeting EC receptors, especially CB1R, may provide a potential therapeutic strategy against obesity and insulin resistance. There are many CB1R antagonists, including inverse agonists and natural compounds that target CB1R and can reduce body weight, adiposity, and hepatic steatosis, and those that improve insulin sensitivity and reverse leptin resistance. Recently, the use of CB1R antagonists was suspended due to adverse central effects, and this caused a major setback in the development of CB1R antagonists. Recent studies, however, have focused on development of antagonists lacking adverse effects. In this review, we detail the important role of CB1R in hepatic insulin resistance and the possible underlying mechanisms, and the therapeutic potential of CB1R targeting is also discussed.”

https://www.ncbi.nlm.nih.gov/pubmed/31035653

https://www.mdpi.com/1422-0067/20/9/2109

Aging circadian rhythms and cannabinoids.

Posted on by
Reply

Neurobiology of Aging

“Numerous aspects of mammalian physiology exhibit cyclic daily patterns known as circadian rhythms. However, studies in aged humans and animals indicate that these physiological rhythms are not consistent throughout the life span. The simultaneous development of disrupted circadian rhythms and age-related impairments suggests a shared mechanism, which may be amenable to therapeutic intervention.

Recently, the endocannabinoid system has emerged as a complex signaling network, which regulates numerous aspects of circadian physiology relevant to the neurobiology of aging.

Agonists of cannabinoid receptor-1 (CB1) have consistently been shown to decrease neuronal activity, core body temperature, locomotion, and cognitive function. Paradoxically, several lines of evidence now suggest that very low doses of cannabinoids are beneficial in advanced age.

One potential explanation for this phenomenon is that these drugs exhibit hormesis-a biphasic dose-response wherein low doses produce the opposite effects of higher doses. Therefore, it is important to determine the dose-, age-, and time-dependent effects of these substances on the regulation of circadian rhythms and other processes dysregulated in aging.

This review highlights 3 fields-biological aging, circadian rhythms, and endocannabinoid signaling-to critically assess the therapeutic potential of endocannabinoid modulation in aged individuals. If the hormetic properties of exogenous cannabinoids are confirmed, we conclude that precise administration of these compounds may bidirectionally entrain central and peripheral circadian clocks and benefit multiple aspects of aging physiology.”

https://www.ncbi.nlm.nih.gov/pubmed/31035036

https://www.sciencedirect.com/science/article/pii/S0197458019300867?via%3Dihub

The Endocannabinoid System Is Present in Rod Outer Segments from Retina and Is Modulated by Light.

Posted on by
Reply

“The aim of the present research was to evaluate if the endocannabinoid system (enzymes and receptors) could be modulated by light in rod outer segment (ROS) from bovine retina. First, we analyzed endocannabinoid 2-arachidonoylglycerol (2-AG) metabolism in purified ROS obtained from dark-adapted (DROS) or light-adapted (LROS) retinas. To this end, diacylglycerol lipase (DAGL), monoacylglycerol lipase (MAGL), and lysophosphatidate phosphohydrolase (LPAP) enzymatic activities were analyzed using radioactive substrates. The protein content of these enzymes and of the receptors to which cannabinoids bind was determined by immunoblotting under light stimulus. Our results indicate that whereas DAGL and MAGL activities were stimulated in retinas exposed to light, no changes were observed in LPAP activity. Interestingly, the protein content of the main enzymes involved in 2-AG metabolism, phospholipase C β1 (PLCβ1), and DAGLα (synthesis), and MAGL (hydrolysis), was also modified by light. PLCβ1 content was increased, while that of lipases was decreased. On the other hand, light produced an increase in the cannabinoid receptors CB1 and CB2 and a decrease in GPR55 protein levels. Taken together, our results indicate that the endocannabinoid system (enzymes and receptors) depends on the illumination state of the retina, suggesting that proteins related to phototransduction phenomena could be involved in the effects observed.”

https://www.ncbi.nlm.nih.gov/pubmed/31016476

https://link.springer.com/article/10.1007%2Fs12035-019-1603-5

Structural Insights into CB1 Receptor Biased Signaling.

Posted on by
Reply

ijms-logo

“The endocannabinoid system has emerged as a promising target for the treatment of numerous diseases, including cancer, neurodegenerative disorders, and metabolic syndromes. Thus far, two cannabinoid receptors, CB1 and CB2, have been discovered, which are found predominantly in the central nervous system (CB1) or the immune system (CB2), among other organs and tissues. CB1 receptor ligands have been shown to induce a complex pattern of intracellular effects. The binding of a ligand induces distinct conformational changes in the receptor, which will eventually translate into distinct intracellular signaling pathways through coupling to specific intracellular effector proteins. These proteins can mediate receptor desensitization, trafficking, or signaling. Ligand specificity and selectivity, complex cellular components, and the concomitant expression of other proteins (which either regulate the CB1 receptor or are regulated by the CB1 receptor) will affect the therapeutic outcome of its targeting. With an increased interest in G protein-coupled receptors (GPCR) research, in-depth studies using mutations, biological assays, and spectroscopic techniques (such as NMR, EPR, MS, FRET, and X-ray crystallography), as well as computational modelling, have begun to reveal a set of concerted structural features in Class A GPCRs which relate to signaling pathways and the mechanisms of ligand-induced activation, deactivation, or activity modulation. This review will focus on the structural features of the CB1 receptor, mutations known to bias its signaling, and reported studies of CB1 receptor ligands to control its specific signaling.”

https://www.ncbi.nlm.nih.gov/pubmed/31013934

https://www.mdpi.com/1422-0067/20/8/1837