Tag Archives: CB(1) and CB(2) receptors

Expression analysis of cannabinoid receptors 1 and 2 in B cells during pregnancy and their role on cytokine production.

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“The endocannabinoid system consists in a family of lipids that binds to and activates cannabinoid receptors. There are two receptors so far described, the cannabinoid receptor 1 (CB1) and 2 (CB2).

In the context of pregnancy, the endocannabinoid system was shown participates in different key aspects of reproductive events. B-lymphocytes are pleiotropic cells belonging to the adaptive arm of the immune system. Besides immunoglobulin production, B-lymphocytes were recently shown to be actively involved in antigen presentation as well as cytokine production, thus playing a central role in immunity.

In this study we first aimed to characterize the expression of CB1 and CB2 receptors in B cells during pregnancy and then analyze the impact of their activation in term of cytokine production by B cells from pregnant and non-pregnant mice.

We observed that the expression of CB1 and CB2 receptors in B-lymphocytes is differentially regulated during pregnancy. While CB2 expression is down regulated CB1 is augmented in B-lymphocytes of pregnant mice.

Additionally, the treatment of activated B-lymphocytes with specific CB1 and CB2 agonists, showed a different response in term of cytokine production. Particularly, CB1 against boosted the production of the anti-inflammatory cytokine IL-10 by activated B-lymphocytes from pregnant mice.”

http://www.ncbi.nlm.nih.gov/pubmed/27163857

Modulation of breast cancer cell viability by a cannabinoid receptor 2 agonist, JWH-015, is calcium dependent

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“Cannabinoid compounds, both nonspecific as well as agonists selective for either cannabinoid receptor 1 (CB1) or cannabinoid receptor 2 (CB2), have been shown to modulate the tumor microenvironment by inducing apoptosis in tumor cells in several model systems.

The mechanism of this modulation remains only partially delineated, and activity induced via the CB1 and CB2 receptors may be distinct despite significant sequence homology and structural similarity of ligands.

The results of this work characterize the actions of a CB2-selective agonist on breast cancer cells in a syngeneic murine model representing how a clinical presentation of cancer progression and metastasis may be significantly modulated by a G-protein-coupled receptor.”

https://www.dovepress.com/modulation-of-breast-cancer-cell-viability-by-a-cannabinoid-receptor-2-peer-reviewed-article-BCTT

Mustard vesicants alter expression of the endocannabinoid system in mouse skin.

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“Vesicants including sulfur mustard (SM) and nitrogen mustard (NM) are bifunctional alkylating agents that cause skin inflammation, edema and blistering. This is associated with alterations in keratinocyte growth and differentiation.

Endogenous cannabinoids, including N-arachidonoylethanolamine (anandamide, AEA) and 2-arachidonoyl glycerol (2-AG), are important in regulating inflammation, keratinocyte proliferation and wound healing.

Their activity is mediated by binding to cannabinoid receptors 1 and 2 (CB1 and CB2), as well as peroxisome proliferator-activated receptor alpha (PPARα). Levels of endocannabinoids are regulated by fatty acid amide hydrolase (FAAH).

We found that CB1, CB2, PPARα and FAAH were all constitutively expressed in mouse epidermis and dermal appendages. Topical administration of NM or SM, at concentrations that induce tissue injury, resulted in upregulation of FAAH, CB1, CB2 and PPARα, a response that persisted throughout the wound healing process.

Inhibitors of FAAH including a novel class of vanillyl alcohol carbamates were found to be highly effective in suppressing vesicant-induced inflammation in mouse skin.

Taken together, these data indicate that the endocannabinoid system is important in regulating skin homeostasis and that inhibitors of FAAH may be useful as medical counter measures against vesicants.”

http://www.ncbi.nlm.nih.gov/pubmed/27125198

WHERE’s MY ENTOURAGE? THE CURIOUS CASE OF 2-oleoylglycerol, 2-linolenoylglycerol, and 2-palmitoylglycerol.

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“2-arachidonoylglycerol (2-AG) is the most abundant endogenous cannabinoid in the brain and an agonist at two cannabinoid receptors (CB1 and CB2). The synthesis, degradation and signaling of 2-AG have been investigated in detail but its relationship to other endogenous monoacylglycerols has not been fully explored.

Three congeners that have been isolated from the CNS are 2-linoleoylglycerol (2-LG), 2-oleoylglycerol (2-OG), and 2-palmitoylglycerol (2-PG). These lipids do not orthosterically bind to cannabinoid receptors but are reported to potentiate the activity of 2-AG, possibly through inhibition of 2-AG degradation. This phenomenon has been dubbed the ‘entourage effect’ and has been proposed to regulate synaptic activity of 2-AG. To clarify the activity of these congeners of 2-AG we tested them in neuronal and cell-based signaling assays.

The signaling profile for these compounds is inconsistent with an entourage effect. None of the compounds inhibited neurotransmission via CB1 in autaptic neurons. Interestingly, each failed to potentiate 2-AG-mediated depolarization-induced suppression of excitation (DSE), behaving instead as antagonists. Examining other signaling pathways we found that 2-OG interferes with agonist-induced CB1 internalization while 2-PG modestly internalizes CB1 receptors. However in tests of pERK, cAMP and arrestin recruitment, none of the acylglycerols altered CB1 signaling.

Our results suggest 1) that these compounds do not serve as entourage compounds under the conditions examined, and 2) that they may instead serve as functional antagonists. Our results suggest that the relationship between 2-AG and its congeners is more nuanced than previously appreciated.”

http://www.ncbi.nlm.nih.gov/pubmed/27117667

Cannabimovone, a Cannabinoid with a Rearranged Terpenoid Skeleton from Hemp

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“An investigation of the polar fractions from a nonpsychotropic variety of hemp (Cannabis sativa L.) afforded cannabimovone, a polar cannabinoid with a rearranged 2(34) abeo-terpenoid skeleton, biogenetically originating from the intramolecular aldolization of a 2′,3′-seco-menthanyl precursor.

The structure of cannabimovone was elucidated by spectroscopic analysis, whereas attempts to mimic its biogenetic derivation from cannabidiol gave only anhydrocannabimovone, the intramolecular oxy-Michael adduct of the crotonized version of the elusive natural products.

Biological evaluation of cannabimovone against metabotropic (CB1, CB2) and ionotropic (TRPs) cannabinoid receptors showed a significant activity only for ionotropic receptors, especially TRPV1, whereas anhydrocannabimovone exhibited strong activity at both ionotropic and metabotropic cannabinoid receptors.

Overall, the biological profile of anhydrocannabimovone was somewhat similar to that of THC, suggesting a remarkable tolerance to constitutional and configurational changes.”

http://onlinelibrary.wiley.com/doi/10.1002/ejoc.200901464/abstract

The Endocannabinoid System: An Osteopathic Perspective

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“A person is the product of dynamic interaction between body, mind, and spirit—This holistic principle is exemplified by cannabinoid receptors, which span the field of psychoneuroimmunology. Taken together, CB1, CB2, and their endocannabinoid ligands represent a microcosm of mind-body medicine. The primary purpose of the current article is to review the expanding endocannabinoid literature beginning with exogenous compounds—Cannabis and plant cannabinoids—and then shift to the endogenous system, highlighting embryology and development, neuroprotection, autonomics and immunity, inflammation, apoptosis, hunger and feeding, and nociception and pain.” http://jaoa.org/article.aspx?articleid=2093607

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

An update on peroxisome proliferator-activated receptor (PPAR) activation by cannabinoids.

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“Some cannabinoids activate the different isoforms of peroxisome proliferator-activated receptors (PPARs; α, β and γ), as shown through the use of reporter gene assays, binding studies, selective antagonists and knockout studies.

Activation of all isoforms, but primarily PPARα and γ, mediate some (but not all) of the analgesic, neuroprotective, neuronal function modulation, anti-inflammatory, metabolic, anti-tumoral, gastrointestinal and cardiovascular effects of some cannabinoids, often in conjunction with activation of the more traditional target sites of action such as CB1 , CB2 and TRPV1.

PPARs also mediate some of the effects of inhibitors of endocannabinoid degradation or transport. Cannabinoids may be chaperoned to the PPARs by fatty acid binding proteins (FABPs).

The aim of this review is to update the evidence supporting PPAR activation by cannabinoids, and review the physiological responses to cannabinoids that are mediated, and not mediated, by PPAR activation.”

http://www.ncbi.nlm.nih.gov/pubmed/27077495

Cannabinoid Receptors CB1 and CB2 Modulate the Electroretinographic Waves in Vervet Monkeys.

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“The expression patterns of the cannabinoid receptor type 1 (CB1R) and the cannabinoid receptor type 2 (CB2R) are well documented in rodents and primates.

In vervet monkeys, CB1R is present in the retinal neurons (photoreceptors, horizontal cells, bipolar cells, amacrine cells, and ganglion cells) and CB2R is exclusively found in the retinal glia (Müller cells). However, the role of these cannabinoid receptors in normal primate retinal function remains elusive.

Using full-field electroretinography in adult vervet monkeys, we recorded changes in neural activity following the blockade of CB1R and CB2R by the intravitreal administration of their antagonists (AM251 and AM630, resp.) in photopic and scotopic conditions.

Our results show that AM251 increases the photopic a-wave amplitude at high flash intensities, whereas AM630 increases the amplitude of both the photopic a- and b-waves.In scotopic conditions, both blockers increased the b-wave amplitude but did not change the a-wave amplitude.

These findings suggest an important role of CB1R and CB2R in primate retinal function.”

http://www.ncbi.nlm.nih.gov/pubmed/27069692

Distinctive effects of eicosapentaenoic and docosahexaenoic acids in regulating neural stem cell fate are mediated via endocannabinoid signalling pathways.

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“Emerging evidence suggests a complex interplay between the endocannabinoid system, omega-3 fatty acids and the immune system in the promotion of brain self-repair.

However, it is unknown if all omega-3 fatty acids elicit similar effects on adult neurogenesis and if such effects are mediated or regulated by interactions with the endocannabinoid system. This study investigated the effects of DHA and EPA on neural stem cell (NSC) fate and the role of the endocannabinoid signalling pathways in these effects.

EPA, but not DHA, significantly increased proliferation of NSCs compared to controls, an effect associated with enhanced levels of the endocannabinoid 2-arachidonylglycerol (2-AG) and p-p38 MAPK, effects attenuated by pre-treatment with CB1 (AM251) or CB2 (AM630) receptor antagonists.

Furthermore, in NSCs derived from IL-1β deficient mice, EPA significantly decreased proliferation and p-p38 MAPK levels compared to controls, suggesting a key role for IL-1β signalling in the effects observed. Although DHA similarly increased 2-AG levels in wild-type NSCs, there was no concomitant increase in proliferation or p-p38 MAPK activity. In addition, in NSCs from IL-1β deficient mice, DHA significantly increased proliferation without effects on p-P38 MAPK, suggesting effects of DHA are mediated via alternative signalling pathways.

These results provide crucial new insights into the divergent effects of EPA and DHA in regulating NSC proliferation and the pathways involved, and highlight the therapeutic potential of their interplay with endocannabinoid signalling in brain repair.”

http://www.ncbi.nlm.nih.gov/pubmed/27044662