Tag Archives: antagonists

The effect of five day dosing with THCV on THC-induced cognitive, psychological and physiological effects in healthy male human volunteers: A placebo-controlled, double-blind, crossover pilot trial.

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“Cannabis is mostly grown under illegal and unregulated circumstances, which seems to favour a product increasingly high in its main cannabinoid ∆-9-tetrahydrocannabinol (THC). ∆-9-tetrahydrocannabivarin (THCV) is a relatively untested cannabinoid which is said to be a cannabinoid receptor neutral antagonist, and may inhibit the effects of THC.

In this first study of THC and THCV, THCV inhibited some of the well-known effects of THC, while potentiating others.”

http://www.ncbi.nlm.nih.gov/pubmed/26577065

 

The cannabinoid system in the retrosplenial cortex modulates fear memory consolidation, reconsolidation, and extinction.

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“Despite the fact that the cannabinoid receptor type 1 (CB1R) plays a pivotal role in emotional memory processing in different regions of the brain, its function in the retrosplenial cortex (RSC) remains unknown. Here, using contextual fear conditioning in rats, we showed that a post-training intra-RSC infusion of the CB1R antagonist AM251 impaired, and the agonist CP55940 improved, long-term memory consolidation. Additionally, a post-reactivation infusion of AM251 enhanced memory reconsolidation, while CP55940 had the opposite effect. Finally, AM251 blocked extinction, whereas CP55940 facilitated it and maintained memory extinguished over time. Altogether, our data strongly suggest that the cannabinoid system of the RSC modulates emotional memory.”

http://www.ncbi.nlm.nih.gov/pubmed/26572648

Controlled downregulation of the cannabinoid CB1 receptor provides a promising approach for the treatment of obesity and obesity-derived type 2 diabetes.

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“Increased activity of the endocannabinoid system has emerged as a pathogenic factor in visceral obesity, which is a risk factor for type 2 diabetes mellitus (T2DM).

The endocannabinoid system is composed of at least two G-protein-coupled receptors (GPCRs), the cannabinoid receptor type 1 (CB1), and the cannabinoid receptor type 2 (CB2).

Downregulation of CB1 activity in rodents and humans has proven efficacious to reduce food intake, abdominal adiposity, fasting glucose levels, and cardiometabolic risk factors.

Unfortunately, downregulation of CB1 activity by universally active CB1 inverse agonists has been found to elicit psychiatric side effects, which led to the termination of using globally active CB1 inverse agonists to treat diet-induced obesity.

Interestingly, preclinical studies have shown that downregulation of CB1 activity by CB1 neutral antagonists or peripherally restricted CB1 inverse agonists provided similar anorectic effects and metabolic benefits without psychiatric side effects seen in globally active CB1 inverse agonists.

Furthermore, downregulation of CB1 activity may ease endoplasmic reticulum and mitochondrial stress which are contributors to obesity-induced insulin resistance and type 2 diabetes.

This suggests new approaches for cannabinoid-based therapy in the management of obesity and obesity-related metabolic disorders including type 2 diabetes.”

http://www.ncbi.nlm.nih.gov/pubmed/26498013

GPR55 promotes migration and adhesion of colon cancer cells indicating a role in metastasis.

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“Tumor cell migration and adhesion constitute essential features of metastasis. G protein-coupled receptor 55 (GPR55), a lysophospholipid receptor, has been shown to play an important role in carcinogenesis. Here, we investigated the involvement of GPR55 in migration and metastasis of colon cancer cells.

GPR55 antagonist CID16020046, cannabidiol, a putative GPR55 antagonist, and GPR55 siRNA were used to block GPR55 activity in HCT116 colon cancer cells.

In a mouse model of metastasis, the arrest of HCT116 cancer cells in the liver was reduced after treatment with CID16020046 or cannabidiol.

CONCLUSIONS AND IMPLICATIONS:

GPR55 is involved in the migratory behavior of colon carcinoma cells and may serve as a pharmacological target for the prevention of metastasis.”

http://www.ncbi.nlm.nih.gov/pubmed/26436760

“Pharmacological Characterization of GPR55, A Putative Cannabinoid Receptor”  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2874616/ 

Protection from Radiation-Induced Pulmonary Fibrosis by Peripheral Targeting of Cannabinoid Receptor-1.

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“Radiation-induced pulmonary fibrosis (RIF) is a severe complication of thoracic radiotherapy that limits its dose, intensity, and duration. The contribution of the endocannabinoid signaling system in pulmonary fibrogenesis is not known. Using a well-established mouse model of RIF, we assessed the involvement of cannabinoid receptor-1 (CB1) in the onset and progression of pulmonary fibrosis.

Our results show that CB1 signaling plays a key pathological role in the development of radiation-induced pulmonary inflammation and fibrosis, and peripherally restricted CB1 antagonists may represent a novel therapeutic approach against this devastating complication of radiotherapy/irradiation.”

http://www.ncbi.nlm.nih.gov/pubmed/26426981

“We report for the first time the involvement of cannabinoid receptor 1 (CB1)-mediated signaling in the onset and progression of radiation-induced pulmonary fibrosis (RIF). We were able to delay the onset of RIF by genetic targeting of CB1 receptors as well as by its pharmacological inhibition. Thus, pharmacological targeting of CB1 receptors with peripherally restricted CB1 antagonists void of central nervous system complications may represent a novel strategy to prevent the development of RIF.

In summary, we provide the first evidence on the key pathological role of CB1 signaling in radiation-induced pulmonary fibrogenesis and show that peripherally restricted CB1 antagonists may represent a novel therapeutic approach against this devastating and untreatable complication of radiotherapy/irradiation. Our results also suggest that targeting CB1 may provide benefits in other lung diseases associated with inflammation and fibrosis.”

http://www.atsjournals.org/doi/10.1165/rcmb.2014-0331OC

The Endocannabinoid System: Pivotal Orchestrator of Obesity and Metabolic Disease.

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“The endocannabinoid system (ECS) functions to adjust behavior and metabolism according to environmental changes in food availability.

Its actions range from the regulation of sensory responses to the development of preference for the consumption of calorically-rich food and control of its metabolic handling.

ECS activity is beneficial when access to food is scarce or unpredictable.

However, when food is plentiful, the ECS favors obesity and metabolic disease.

We review recent advances in understanding the roles of the ECS in energy balance, and discuss newly identified mechanisms of action that, after the withdrawal of first generation cannabinoid type 1 (CB1) receptor antagonists for the treatment of obesity, have made the ECS once again an attractive target for therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/26412154

https://www.cell.com/trends/endocrinology-metabolism/fulltext/S1043-2760(15)00140-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS104327601500140X%3Fshowall%3Dtrue

Endocannabinoids and the Cardiovascular System in Health and Disease.

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“The endocannabinoid system is widely distributed throughout the cardiovascular system.

Endocannabinoids play a minimal role in the regulation of cardiovascular function in normal conditions, but are altered in most cardiovascular disorders.

In shock, endocannabinoids released within blood mediate the associated hypotension through CB1 activation. In hypertension, there is evidence for changes in the expression of CB1, and CB1 antagonism reduces blood pressure in obese hypertensive and diabetic patients.

The endocannabinoid system is also upregulated in cardiac pathologies.

This is likely to be cardioprotective, via CB2 and CB1 (lesser extent).

In the vasculature, endocannabinoids cause vasorelaxation through activation of multiple target sites, inhibition of calcium channels, activation of potassium channels, NO production and the release of vasoactive substances. Changes in the expression or function of any of these pathways alter the vascular effect of endocannabinoids.

Endocannabinoids have positive (CB2) and negative effects (CB1) on the progression of atherosclerosis. However, any negative effects of CB1 may not be consequential, as chronic CB1 antagonism in large scale human trials was not associated with significant reductions in atheroma.

In neurovascular disorders such as stroke, endocannabinoids are upregulated and protective, involving activation of CB1, CB2, TRPV1 and PPARα.

Although most of this evidence is from preclinical studies, it seems likely that cannabinoid-based therapies could be beneficial in a range of cardiovascular disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26408169

Endocannabinoids and Metabolic Disorders.

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“The endocannabinoid system (ECS) is known to exert regulatory control on essentially every aspect related to the search for, and the intake, metabolism and storage of calories, and consequently it represents a potential pharmacotherapeutic target for obesity, diabetes and eating disorders.

While the clinical use of the first generation of cannabinoid type 1 (CB1) receptor blockers has been halted due to the psychiatric side effects that their use occasioned, recent research in animals and humans has provided new knowledge on the mechanisms of actions of the ECS in the regulation of eating behavior, energy balance, and metabolism.

In this review, we discuss these recent advances and how they may allow targeting the ECS in a more specific and selective manner for the future development of therapies against obesity, metabolic syndrome, and eating disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26408168

Endocannabinoids and Their Pharmacological Actions.

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“The endocannabinoid system consists of G protein-coupled cannabinoid CB1 and CB2 receptors, of endogenous compounds known as endocannabinoids that can target these receptors, of enzymes that catalyse endocannabinoid biosynthesis and metabolism, and of processes responsible for the cellular uptake of some endocannabinoids.

This review presents in vitro evidence that most or all of the following 13 compounds are probably orthosteric endocannabinoids since they have all been detected in mammalian tissues in one or more investigation, and all been found to bind to cannabinoid receptors, probably to an orthosteric site: anandamide, 2-arachidonoylglycerol, noladin ether, dihomo-γ-linolenoylethanolamide, virodhamine, oleamide, docosahexaenoylethanolamide, eicosapentaenoylethanolamide, sphingosine, docosatetraenoylethanolamide, N-arachidonoyldopamine, N-oleoyldopamine and haemopressin.

In addition, this review describes in vitro findings that suggest that the first eight of these compounds can activate CB1 and sometimes also CB2 receptors and that another two of these compounds are CB1 receptor antagonists (sphingosine) or antagonists/inverse agonists (haemopressin).

Evidence for the existence of at least three allosteric endocannabinoids is also presented. These endogenous compounds appear to target allosteric sites on cannabinoid receptors in vitro, either as negative allosteric modulators of the CB1 receptor (pepcan-12 and pregnenolone) or as positive allosteric modulators of this receptor (lipoxin A4) or of the CB2 receptor (pepcan-12).

Also discussed are current in vitro data that indicate the extent to which some established or putative orthosteric endocannabinoids seem to target non-cannabinoid receptors and ion channels, particularly at concentrations at which they have been found to interact with CB1 or CB2 receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/26408156

The effects of endocannabinoid receptor agonist anandamide and antagonist rimonabant on opioid analgesia and tolerance in rats.

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“The role of the cannabinoid (CB) system in the tolerance to analgesic effect of opioid remains obscure. The aim of the present study was to evaluate the effects of the endocannabinoid nonselective receptor agonist anandamide (AEA) and CB1 receptor antagonist rimonabant (SR141716) on morphine analgesia and tolerance in rats.

The findings suggested that AEA in combination with morphine produced a significant increase in expression of analgesic tolerance to morphine.

Conversely, cannabinoid receptor antagonist SR141716 attenuated morphine analgesic tolerance.

In addition, administration of AEA with morphine increased morphine analgesia.

In conclusion, we observed that the cannabinoid receptor agonist anandamide and CB1 receptor antagonist SR141716 plays a significant role in the opioid analgesia and tolerance.”

http://www.ncbi.nlm.nih.gov/pubmed/26374993