Tag Archives: CB1

The Pharmacological Inhibition of Fatty Acid Amide Hydrolase Prevents Excitotoxic Damage in the Rat Striatum: Possible Involvement of CB1 Receptors Regulation.

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Molecular Neurobiology

“The endocannabinoid system (ECS) actively participates in several physiological processes within the central nervous system.

Among such, its involvement in the downregulation of the N-methyl-D-aspartate receptor (NMDAr) through a modulatory input at the cannabinoid receptors (CBr) has been established. After its production via the kynurenine pathway (KP), quinolinic acid (QUIN) can act as an excitotoxin through the selective overactivation of NMDAr, thus participating in the onset and development of neurological disorders.

In this work, we evaluated whether the pharmacological inhibition of fatty acid amide hydrolase (FAAH) by URB597, and the consequent increase in the endogenous levels of anandamide, can prevent the excitotoxic damage induced by QUIN. URB597 (0.3 mg/kg/day × 7 days, administered before, during and after the striatal lesion) exerted protective effects on the QUIN-induced motor (asymmetric behavior) and biochemical (lipid peroxidation and protein carbonylation) alterations in rats.

URB597 also preserved the structural integrity of the striatum and prevented the neuronal loss (assessed as microtubule-associated protein-2 and glutamate decarboxylase localization) induced by QUIN (1 μL intrastriatal, 240 nmol/μL), while modified the early localization patterns of CBr1 (CB1) and NMDAr subunit 1 (NR1).

Altogether, these findings support the concept that the pharmacological manipulation of the endocannabinoid system plays a neuroprotective role against excitotoxic insults in the central nervous system.”

 https://www.ncbi.nlm.nih.gov/pubmed/29802570
https://link.springer.com/article/10.1007%2Fs12035-018-1129-2

Computational investigation on the binding modes of Rimonabant analogues with CB1 and CB2.

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“The human cannabinoid G protein coupled receptor 1 (CB1) is highly expressed in central nervous system. CB1-selective antagonists show therapeutic promise in a wide range of disorders, such as obesity-related metabolic disorders, dyslipidemia, drug abuse and type 2 diabetes.

Rimonabant (SR141716A), MJ08 and MJ15 are selective CB1 antagonists with selectivity >1000 folds over CB2 despite of 42% sequence identity between CB1 and CB2. The integration of homology modeling, automated molecular docking and molecular dynamics simulation were used to investigate the binding modes of these selective inverse agonists/antagonists with CB1 and CB2 and their selectivity.

Our analyses showed that the hydrophobic interactions between ligands and hydrophobic pockets of CB1 account for the main binding affinity. In addition, instead of interacting with ligands directly as previously reported, the Lys1923.28in CB1 was engaged in indirect interactions with ligands to keep inactive-state CB1 stable by forming the salt bridge with Asp1762.63 . Lastly, our analyses indicated that the selectivity of these antagonists came from the difference in geometry shapes of binding pockets of CB1 and CB2.

The present study could guide future experimental works on these receptors and has the guiding significance for the design of functionally selective drugs targeting CB1 or CB2 receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/29797785

https://onlinelibrary.wiley.com/doi/abs/10.1111/cbdd.13337

Endocannabinoid system and pathophysiology of adipogenesis: current management of obesity.

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“The endocannabinoids are now known as novel and important regulators of energy metabolism and homeostasis.

The endocrine functions of white adipose are chiefly involved in the control of whole-body metabolism, insulin sensitivity and food intake. Adipocytes produce hormones, such as leptin and adiponectin, that can improve insulin resistance or peptides, such as TNF-α, that elicit insulin resistance. Adipocytes express specific receptors, such as peroxisome proliferator-activated receptor (PPAR)-γ, which serve as adipocyte targets for insulin sensitizers such as thiazolidinediones.

Recently, endocannabinoids and related compounds were identified in human fat cells.

The endocannabinoid system consists primarily of two receptors, cannabinoid (CB)1 and CB2, their endogenous ligands termed endocannabinoids and the enzymes responsible for ligand biosynthesis and degradation.

The endocannabinoids 2-arachidonylglycerol and anandamide or N-arachidonoylethanolamine increase food intake and promote weight gain in animals. Rimonabant, a selective CB1 blocker, reduces food intake and body weight in animals and humans.”

 https://www.ncbi.nlm.nih.gov/pubmed/29788669
https://www.futuremedicine.com/doi/10.2217/17410541.4.3.307

Synthesis of 13 C6 -labeled, dual-target inhibitor of Cannabinoid-1 receptor (CB1 R) and inducible nitric oxide synthase (iNOS).

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“Cannabinoid-1 receptor (CB1 R) antagonists/inverse agonists have great potential in the treatment of metabolic disorders like dyslipidemia, type 2 diabetes and non-alcoholic steatohepatitis (NASH).

CB1 R inverse agonists have also been reported to be effective in mitigating fibrotic disorders in murine models.

Inducible nitric oxide synthase is another promising target implicated in fibrotic and inflammatory disorders.

We have disclosed MRI-1867 as a potent and selective, peripherally acting dual-target inhibitor of the cannabinoid receptor (CB1 R) and inducible nitric oxide synthase (iNOS).

Herein, we report the synthesis of [13 C6 ]-MRI-1867 as a racemate from commercially available chlorobenzene-13 C6 as the starting, stable-isotope label reagent. The racemic [13 C6 ]-MRI-1867 was further processed to the stable-isotope labeled enantiopure compounds utilizing chiral chromatography. Both racemic [13 C6]-MRI-1867 and S-13 C6 -MRI-1867 will be used to quantitate unlabeled S-MRI-1867 during clinical DMPK studies and will be used as an LC-MS/MS bioanalytical standard.”

https://www.ncbi.nlm.nih.gov/pubmed/29790591

https://onlinelibrary.wiley.com/doi/abs/10.1002/jlcr.3639

Anandamide Revisited: How Cholesterol and Ceramides Control Receptor-Dependent and Receptor-Independent Signal Transmission Pathways of a Lipid Neurotransmitter.

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“Anandamide is a lipid neurotransmitter derived from arachidonic acid, a polyunsaturated fatty acid.

The chemical differences between anandamide and arachidonic acid result in a slightly enhanced solubility in water and absence of an ionisable group for the neurotransmitter compared with the fatty acid. In this review, we first analyze the conformational flexibility of anandamide in aqueous and membrane phases. We next study the interaction of the neurotransmitter with membrane lipids and discuss the molecular basis of the unexpected selectivity of anandamide for cholesterol and ceramide from among other membrane lipids.

We show that cholesterol behaves as a binding partner for anandamide, and that following an initial interaction mediated by the establishment of a hydrogen bond, anandamide is attracted towards the membrane interior, where it forms a molecular complex with cholesterol after a functional conformation adaptation to the apolar membrane milieu.

The complex is then directed to the anandamide cannabinoid receptor (CB1) which displays a high affinity binding pocket for anandamide. We propose that cholesterol may regulate the entry and exit of anandamide in and out of CB1 by interacting with low affinity cholesterol recognition sites (CARC and CRAC) located in transmembrane helices.

The mirror topology of cholesterol binding sites in the seventh transmembrane domain is consistent with the delivery, extraction and flip-flop of anandamide through a coordinated cholesterol-dependent mechanism. The binding of anandamide to ceramide illustrates another key function of membrane lipids which may occur independently of protein receptors.

Interestingly, ceramide forms a tight complex with anandamide which blocks the degradation pathway of both lipids and could be exploited for anti-cancer therapies.”

https://www.ncbi.nlm.nih.gov/pubmed/29789479
http://www.mdpi.com/2218-273X/8/2/31

“The endogenous cannabinoid anandamide inhibits human breast cancer cell proliferation” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC20983/

“The endogenous cannabinoid, anandamide, induces cell death in colorectal carcinoma cells: a possible role for cyclooxygenase 2”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1774787/

Pharmacological properties of cannabidiol in the treatment of psychiatric disorders: a critical overview.

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“Cannabidiol (CBD) represents a new promising drug due to a wide spectrum of pharmacological actions. In order to relate CBD clinical efficacy to its pharmacological mechanisms of action, we performed a bibliographic search on PUBMED about all clinical studies investigating the use of CBD as a treatment of psychiatric symptoms.

Findings to date suggest that (a) CBD may exert antipsychotic effects in schizophrenia mainly through facilitation of endocannabinoid signalling and cannabinoid receptor type 1 antagonism; (b) CBD administration may exhibit acute anxiolytic effects in patients with generalised social anxiety disorder through modification of cerebral blood flow in specific brain sites and serotonin 1A receptor agonism; (c) CBD may reduce withdrawal symptoms and cannabis/tobacco dependence through modulation of endocannabinoid, serotoninergic and glutamatergic systems; (d) the preclinical pro-cognitive effects of CBD still lack significant results in psychiatric disorders.

In conclusion, current evidences suggest that CBD has the ability to reduce psychotic, anxiety and withdrawal symptoms by means of several hypothesised pharmacological properties. However, further studies should include larger randomised controlled samples and investigate the impact of CBD on biological measures in order to correlate CBD’s clinical effects to potential modifications of neurotransmitters signalling and structural and functional cerebral changes.”

https://www.ncbi.nlm.nih.gov/pubmed/29789034

https://www.cambridge.org/core/journals/epidemiology-and-psychiatric-sciences/article/pharmacological-properties-of-cannabidiol-in-the-treatment-of-psychiatric-disorders-a-critical-overview/D7FD68F40CF30CBB48A1025C66873F26

Controlled-Deactivation CB1 Receptor Ligands as a Novel Strategy to Lower Intraocular Pressure.

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“Nearly half a century has passed since the demonstration that cannabis and its chief psychoactive component Δ⁸-THC lowers intraocular pressure (IOP).

Elevated IOP remains the chief hallmark and therapeutic target for glaucoma, a condition that places millions at risk of blindness. It is likely that Δ⁸-THC exerts much of its IOP-lowering effects via the activation of CB1 cannabinoid receptors.

However, the initial promise of CB1 as a target for treating glaucoma has not thus far translated into a credible therapeutic strategy. We have recently shown that blocking monoacylglycerol lipase (MAGL), an enzyme that breaks the endocannabinoid 2-arachidonoyl glycerol (2-AG), substantially lowers IOP.

Another strategy is to develop cannabinoid CB1 receptor agonists that are optimized for topical application to the eye. Recently we have reported on a controlled-deactivation approach where the “soft” drug concept of enzymatic deactivation was combined with a “depot effect” that is commonly observed with Δ⁸-THC and other lipophilic cannabinoids.

This approach allowed us to develop novel cannabinoids with a predictable duration of action and is particularly attractive for the design of CB1 activators for ophthalmic use with limited or no psychoactive effects.

We have tested a novel class of compounds using a combination of electrophysiology in autaptic hippocampal neurons, a well-characterized model of endogenous cannabinoid signaling, and measurements of IOP in a mouse model.

We now report that AM7410 is a reasonably potent and efficacious agonist at CB1 in neurons and that it substantially (30%) lowers IOP for as long as 5 h after a single topical treatment. This effect is absent in CB1 knockout mice.

Our results indicate that the direct targeting of CB1 receptors with controlled-deactivation ligands is a viable approach to lower IOP in a murine model and merits further study in other model systems.”

https://www.ncbi.nlm.nih.gov/pubmed/29786643

http://www.mdpi.com/1424-8247/11/2/50

A peripherally restricted cannabinoid 1 receptor agonist as a novel analgesic in cancer-induced bone pain.

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“Many malignant cancers, including breast cancer, have a propensity to invade bones, leading to excruciating bone pain.

Opioids are the primary analgesics used to alleviate this cancer-induced bone pain (CIBP) but are associated with numerous severe side effects, including enhanced bone degradation, which significantly impairs patients’ quality of life.

In contrast, agonists activating only peripheral CB1 receptors (CB1Rs) have been shown to effectively alleviate multiple chronic pain conditions with limited side effects, yet no studies have evaluated their role(s) in CIBP.

Here, we demonstrate for the first time that a peripherally selective CB1R agonist can effectively suppress CIBP.

Overall, our studies demonstrate that CIBP can be effectively managed by using a peripherally restricted CB1R agonist, PrNMI, without inducing dose-limiting central side effects.

Thus, targeting peripheral CB1Rs could be an alternative therapeutic strategy for the treatment of CIBP.”

 https://www.ncbi.nlm.nih.gov/pubmed/29781960
https://insights.ovid.com/crossref?an=00006396-900000000-98957

The endocannabinoid-alcohol crosstalk: recent advances on a bi-faceted target.

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“Increasing evidence focuses on the endocannabinoid system as a relevant player in the induction of aberrant synaptic plasticity and related addictive phenotype following chronic excessive alcohol drinking.

Besides, the endocannabinoid system is implicated in the pathogenesis of alcoholic liver disease.

Interestingly, whereas the involvement of CB1 cannabinoid receptors in alcohol rewarding properties is established, the central and peripheral action of CB2 cannabinoid signalling is still to be elucidated.

This review aims at giving the input to deepen knowledge on the role of the endocannabinoid system, highlighting the advancing evidence that suggests that CB1 and CB2 receptors may play opposite roles in the regulation of both the reinforcing properties of alcohol in the brain and the mechanisms responsible for cell injury and inflammation in the hepatic tissue.

The manipulation of the endocannabinoid system could represent a bi-faceted strategy to counteract alcohol-related dysfunction in central transmission and liver structural and functional disarrangement.”

https://www.ncbi.nlm.nih.gov/pubmed/29770478

https://onlinelibrary.wiley.com/doi/abs/10.1111/1440-1681.12967

Cannabinoid 1 receptors are expressed in nociceptive primary sensory neurons.

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 Neuroscience

“Expression of cannabinoid 1 (CB1) and vanilloid 1 (VR1) receptor proteins was studied in adult, cultured rat dorsal root ganglion neurons. Immunostaining of CB1 receptors alone produced labelling in 57+/-2% of the cultured dorsal root ganglion neurons (n=3 cultures). The area of the labelled cells was between 200 and 800 microm(2) with an average of 527+/-68 microm(2). VR1 immunolabelling revealed immunopositivity in 42+/-6% of the total population of dorsal root ganglion neurons. Cells showing VR1-like immunopositivity had an area between 200 and 600 microm(2). The mean area of the VR1-like immunopositive neurons was 376+/-61 microm(2). Double immunostaining with antisera raised against the CB1 and VR1 receptor proteins, showed a high degree of co-expression between CB1 and VR1 receptors. An average of 82+/-3% of the CB1-like immunopositive cells also showed VR1-like immunoreactivity (n=3 cultures) while 98+/-2% of the VR1-like immunolabelled neurons showed CB1 receptor-like immunostaining (n=3 cultures). Our data suggests that nociceptive primary sensory neurons co-express CB1 and VR1 receptors to a very high degree. We propose that this may provide an anatomical basis for a powerful combination of VR1 mediated excitation and CB1-mediated inhibition of nociceptive responses at central and peripheral terminals of nociceptive primary afferents.”

https://www.ncbi.nlm.nih.gov/pubmed/11036202

https://www.sciencedirect.com/science/article/abs/pii/S0306452200003894