The therapeutic role of cannabinoid receptors and its agonists or antagonists in Parkinson’s disease.

Progress in Neuro-Psychopharmacology and Biological Psychiatry“Parkinson’s disease (PD) is a neurodegenerative disease and its characteristic is the progressive degeneration of dopaminergic neurons within the substantia nigra (SN) of the midbrain. There is hardly any clinically proven efficient therapeutics for its cure in several recent preclinical advances proposed to treat PD.

Recent studies have found that the endocannabinoid signaling system in particular the comprised two receptors, CB1 and CB2 receptors, has a significant regulatory function in basal ganglia and is involved in the pathogenesis of PD. Therefore, adding new insights into the biochemical interactions between cannabinoids and other signaling pathways may help develop new pharmacological strategies.

Factors of the endocannabinoid system (ECS) are abundantly expressed in the neural circuits of basal ganglia, where they interact interactively with glutamatergic, γ-aminobutyric acid-ergic (GABAergic), and dopaminergic signaling systems. Although preclinical studies on PD are promising, the use of cannabinoids at the clinical level has not been thoroughly studied.

In this review, we evaluated the available evidence and reviewed the involvement of ECS in etiologies, symptoms and treatments related to PD. Since CB1 and CB2 receptors are the two main receptors of endocannabinoids, we primarily put the focus on the therapeutic role of CB1 and CB2 receptors in PD. We will try to determine future research clues that will help understand the potential therapeutic benefits of the ECS in the treatment of PD, aiming to open up new strategies and ideas for the treatment of PD.”

https://www.ncbi.nlm.nih.gov/pubmed/31442553

https://www.sciencedirect.com/science/article/pii/S0278584619302210?via%3Dihub

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Prediction and Experimental Confirmation of Novel Peripheral Cannabinoid-1 Receptor Antagonists.

Go to Volume 0, Issue ja “Small molecules targeting peripheral CB1 receptors have therapeutic potential in a variety of disorders including obesity-related, hormonal and metabolic abnormalities, while avoiding the psychoactive effects in the CNS.

We applied our in house algorithm, Iterative Stochastic Elimination, to produce a ligand-based model that distinguishes between CB1R antagonists and random molecules, by physico-chemical properties only. We screened ~2 million commercially available molecules, and found that about 500 of them are potential candidates to antagonize CB1R. We applied a few criteria for peripheral activity and narrowed that set down to 30 molecules, out of which 15 could be purchased. Ten out of those 15 showed good affinity to CB1R and two of them with nanomolar affinities (Ki of ~400 nM). The eight molecules with top affinities were tested for activity: two compounds are pure antagonists, and five others are inverse agonists.

These molecules are now being examined in vivo for their peripheral vs. central distribution, and subsequently will be tested for their effects on obesity in small animals.”

https://www.ncbi.nlm.nih.gov/pubmed/31433190

https://pubs.acs.org/doi/10.1021/acs.jcim.9b00577

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Cannabidiol and the Remainder of the Plant Extract Modulate the Effects of Δ9-Tetrahydrocannabinol on Fear Memory Reconsolidation.

Image result for frontiers in behavioral neuroscience “Δ9-Tetrahydrocannabinol (THC, a CB1 receptor agonist) and Cannabidiol (CBD, a non-competitive antagonist of endogenous CB1 and CB2 ligands) are two primary components of Cannabis species, and may modulate fear learning in mammals.

The CB1 receptor is widely distributed throughout the cortex and some limbic regions typically associated with fear learning. Humans with posttraumatic disorder (PTSD) have widespread upregulation of CB1 receptor density and reduced availability of endogenous cannabinoid anandamide, suggesting a role for the endocannabinoid system in PTSD.

Pharmacological blockade of memory reconsolidation following recall of a conditioned response modulates the expression of learned fear and may represent a viable target for the development of new treatments for PTSD.

In this study, we focused on assessing the impact of the key compounds of the marijuana plant both singly and, more importantly, in concert on attenuation of learned fear. Specifically, we assessed the impact of THC, CBD, and/or the remaining plant materials (post-extraction; background material), on reconsolidation of learned fear.

Results: CBD alone, but not THC alone, significantly attenuated fear memory reconsolidation when administered immediately after recall. The effect persisted for at least 7 days. A combination of CBD and THC also attenuated the fear response. Plant BM also significantly attenuated reconsolidation of learned fear both on its own and in combination with THC and CBD. Finally, THC attenuated reconsolidation of learned fear only when co-administered with CBD or plant BM.

Conclusion: CBD may provide a novel treatment strategy for targeting fear-memories. Furthermore, plant BM also significantly attenuated the fear response. However, whereas THC alone had no significant effects, its effects were modulated by the addition of other compounds. Future research should investigate some of the other components present in the plant BM (such as terpenes) for their effects alone, or in combination with isolated pure cannabinoids, on fear learning.”

https://www.ncbi.nlm.nih.gov/pubmed/31417379

https://www.frontiersin.org/articles/10.3389/fnbeh.2019.00174/full

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Cannabinoid receptor-1 antagonism: a new perspective on treating a murine schistosomal liver fibrosis model.

 SciELO - Scientific Electronic Library Online“Formation of schistosomal granulomata surrounding the ova can result in schistosomiasis-associated liver fibrosis (SSLF). The current standard of treatment is praziquantel (PZQ), which cannot effectively reverse SSLF.

The role of the cannabinoid (CB) receptor family in liver fibrosis has recently been highlighted.

This study aimed to assess the therapeutic effect of CB1 receptor antagonism in reversing SSLF in a murine model of Schistosoma mansoni infection.

MAIN CONCLUSIONS:

Combining PZQ with CB1 receptor antagonists yielded the best results in reversing SSLF. To our knowledge, this is the first study to test this regimen in S. mansoni infection.”

https://www.ncbi.nlm.nih.gov/pubmed/31389521

http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02762019000100338&tlng=en

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Targeting Cannabinoid Signaling in the Immune System: “High”-ly Exciting Questions, Possibilities, and Challenges

Image result for frontiers in immunology“It is well known that certain active ingredients of the plants of Cannabis genus, i.e., the “phytocannabinoids” [pCBs; e.g., (−)-trans9-tetrahydrocannabinol (THC), (−)-cannabidiol, etc.] can influence a wide array of biological processes, and the human body is able to produce endogenous analogs of these substances [“endocannabinoids” (eCB), e.g., arachidonoylethanolamine (anandamide, AEA), 2-arachidonoylglycerol (2-AG), etc.]. These ligands, together with multiple receptors (e.g., CB1 and CB2 cannabinoid receptors, etc.), and a complex enzyme and transporter apparatus involved in the synthesis and degradation of the ligands constitute the endocannabinoid system (ECS), a recently emerging regulator of several physiological processes. The ECS is widely expressed in the human body, including several members of the innate and adaptive immune system, where eCBs, as well as several pCBs were shown to deeply influence immune functions thereby regulating inflammation, autoimmunity, antitumor, as well as antipathogen immune responses, etc. Based on this knowledge, many in vitro and in vivo studies aimed at exploiting the putative therapeutic potential of cannabinoid signaling in inflammation-accompanied diseases (e.g., multiple sclerosis) or in organ transplantation, and to dissect the complex immunological effects of medical and “recreational” marijuana consumption. Thus, the objective of the current article is (i) to summarize the most recent findings of the field; (ii) to highlight the putative therapeutic potential of targeting cannabinoid signaling; (iii) to identify open questions and key challenges; and (iv) to suggest promising future directions for cannabinoid-based drug development.

Active Components of Cannabis sativa (Hemp)—Phytocannabinoids (pCBs) and Beyond

It is known since ancient times that consumption of different parts of the plant Cannabis sativa can lead to psychotropic effects. Moreover, mostly, but not exclusively because of its potent analgesic actions, it was considered to be beneficial in the management of several diseases. Nowadays it is a common knowledge that these effects were mediated by the complex mixture of biologically active substances produced by the plant. So far, at least 545 active compounds have been identified in it, among which, the best-studied ones are the so-called pCBs. It is also noteworthy that besides these compounds, ca. 140 different terpenes [including the potent and selective CB2 agonist sesquiterpene β-caryophyllene (BCP)], multiple flavonoids, alkanes, sugars, non-cannabinoid phenols, phenylpropanoids, steroids, fatty acids, and various nitrogenous compounds can be found in the plant, individual biological actions of which are mostly still nebulous. Among the so far identified > 100 pCBs, the psychotropic (−)-trans9-tetrahydrocannabinol (THC) and the non-psychotropic (−)-cannabidiol (CBD) are the best-studied ones, exerting a wide-variety of biological actions [including but not exclusively: anticonvulsive, analgesic, antiemetic, and anti inflammatory effects]. Of great importance, pCBs have been shown to modulate the activity of a plethora of cellular targets, extending their impact far beyond the “classical” (see above) cannabinoid signaling. Indeed, besides being agonists [or in some cases even antagonists of CB1 and CB2 cannabinoid receptors, some pCBs were shown to differentially modulate the activity of certain TRP channels, PPARs, serotonin, α adrenergic, adenosine or opioid receptors, and to inhibit COX and lipoxygenase enzymes, FAAH, EMT, etc.. Moreover, from a clinical point-of-view, it should also be noted that pCBs can indirectly modify pharmacokinetics of multiple drugs (e.g., cyclosporine A) by interacting with several cytochrome P 450 (CYP) enzymes. Taken together, pCBs can be considered as multitarget polypharmacons, each of them having unique “molecular fingerprints” created by the characteristic activation/inhibition pattern of its locally available cellular targets.

Concluding Remarks—Lessons to Learn from Cannabis

Research efforts of the past few decades have unambiguously evidenced that ECS is one of the central orchestrators of both innate and adaptive immune systems, and that pure pCBs as well as complex cannabis-derivatives can also deeply influence immune responses. Although, many open questions await to be answered, pharmacological modulation of the (endo)cannabinoid signaling, and restoration of the homeostatic eCB tone of the tissues augur to be very promising future directions in the management of several pathological inflammation-accompanied diseases. Moreover, in depth analysis of the (quite complex) mechanism-of-action of the most promising pCBs is likely to shed light to previously unknown immune regulatory mechanisms and can therefore pave new “high”-ways toward developing completely novel classes of therapeutic agents to manage a wide-variety of diseases.”

https://www.frontiersin.org/articles/10.3389/fimmu.2017.01487/full

www.frontiersin.org

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Pharmacology of Medical Cannabis.

 “The Cannabis plant has been used for many of years as a medicinal agent in the relief of pain and seizures. It contains approximately 540 natural compounds including more than 100 that have been identified as phytocannabinoids due to their shared chemical structure. The predominant psychotropic component is Δ9-tetrahydrocannabinol (Δ9-THC), while the major non-psychoactive ingredient is cannabidiol (CBD). These compounds have been shown to be partial agonists or antagonists at the prototypical cannabinoid receptors, CB1 and CB2. The therapeutic actions of Δ9-THC and CBD include an ability to act as analgesics, anti-emetics, anti-inflammatory agents, anti-seizure compounds and as protective agents in neurodegeneration. However, there is a lack of well-controlled, double blind, randomized clinical trials to provide clarity on the efficacy of either Δ9-THC or CBD as therapeutics. Moreover, the safety concerns regarding the unwanted side effects of Δ9-THC as a psychoactive agent preclude its widespread use in the clinic. The legalization of cannabis for medicinal purposes and for recreational use in some regions will allow for much needed research on the pharmacokinetics and pharmocology of medical cannabis. This brief review focuses on the use of cannabis as a medicinal agent in the treatment of pain, epilepsy and neurodegenerative diseases. Despite the paucity of information, attention is paid to the mechanisms by which medical cannabis may act to relieve pain and seizures.”

https://www.ncbi.nlm.nih.gov/pubmed/31332738

https://link.springer.com/chapter/10.1007%2F978-3-030-21737-2_8

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Endocannabinoids and endocannabinoid-like compounds modulate hypoxia-induced permeability in CaCo-2 cells via CB1, TRPV1, and PPARα.

Biochemical Pharmacology“We have previously reported that endocannabinoids modulate permeability in Caco-2 cells under inflammatory conditions and hypothesised in the present study that endocannabinoids could also modulate permeability in ischemia/reperfusion.

CONCLUSIONS AND IMPLICATIONS:

A variety of endocannabinoids and endocannabinoid-like compounds modulate Caco-2 permeability in hypoxia/reoxygenation, which involves multiple targets, depending on whether the compounds are applied to the basolateral or apical membrane. CB1 antagonism and TRPV1 or PPARα agonism may represent novel therapeutic targets against several intestinal disorders associated with increased permeability.”

https://www.ncbi.nlm.nih.gov/pubmed/31325449

https://www.sciencedirect.com/science/article/abs/pii/S0006295219302722?via%3Dihub

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Overcoming the psychiatric side effects of the cannabinoid CB1 receptor antagonists: Current approaches for therapeutics development.

“The cannabinoid receptor 1 (CBR1) is involved in a variety of physiological pathways and has long been considered a golden target for therapeutic manipulation. A large body of evidence in both animal and human studies suggests that CB1R antagonism is highly effective for the treatment of obesity, metabolic disorders and drug addiction. However, the first-in-class CB1R antagonist/inverse agonist, rimonabant, though demonstrating effectiveness for obesity treatment and smoking cessation, displays serious psychiatric side effects, including anxiety, depression and even suicidal ideation, resulting in its eventual withdrawal from the European market. Several strategies are currently being pursued to circumvent the mechanisms leading to these side effects by developing neutral antagonists, peripherally restricted ligands, and allosteric modulators. In this review, we describe the progress in the development of therapeutics targeting the cannabinoid receptor 1 in the last two decades.”

https://www.ncbi.nlm.nih.gov/pubmed/31284863

http://www.eurekaselect.com/173316/article

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Quetiapine induces myocardial necroptotic cell death through bidirectional regulation of cannabinoid receptors.

Toxicology Letters

“Quetiapine is a common atypical antipsychotic used to treat mental disorders such as schizophrenia, bipolar disorder, and major depressive disorder. There has been increasing number of reports describing its cardiotoxicity. However, the molecular mechanisms underlying quetiapine-induced myocardial injury remain largely unknown.

Herein, we reported a novel cell death type, quetiapine-induced necroptosis, which accounted for quetiapine cardiotoxicity in mice and proposed novel therapeutic strategies.

Quetiapine-treated hearts showed inflammatory infiltration and evident fibrosis after 21-day continuous injection. The specific increases of protein levels of RIP3, MLKL and the phosphorylation of MLKL showed that quetiapine-induced necroptotic cell death both in vivo and in vitro. Pharmacologic blockade of necroptosis using its specific inhibitor Necrostatin-1 attenuated quetiapine-induced myocardial injury in mice.

In addition, quetiapine imbalanced the endocannabinoid system and caused opposing effects on two cannabinoid receptors (CB1R and CB2R).

Specific antagonists of CB1R (AM 281, Rimonabant), but not its agonist ACEA significantly ameliorated the heart histopathology induced by chronic quetiapine exposure. By contrast, specific agonists of CB2R (JWH-133, AM 1241), but not its antagonist AM 630 exerted beneficial roles against quetiapine cardiotoxicity.

The protective agents (AM 281, Rimonabant, AM 1241, and JWH-133) consistently inactivated the quetiapine-induced necroptosis signaling. Quetiapine bidirectionally regulates cannabinoid receptors and induces myocardial necroptosis, leading to cardiac toxic effects.

Therefore, pharmacologic inhibition of CB1R or activation of CB2R represents promising therapeutic strategies against quetiapine-induced cardiotoxicity.”

https://www.ncbi.nlm.nih.gov/pubmed/31220554

https://www.sciencedirect.com/science/article/pii/S0378427419301766?via%3Dihub

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Alcohol-induced conditioned place preference is modulated by CB2 cannabinoid receptors and modifies levels of endocannabinoids in the mesocorticolimbic system.

Pharmacology Biochemistry and Behavior

“The endocannabinoid (eCB) system is a particularly important neuronal mechanism implicated in alcohol use disorders. Animal models are key to broadening our knowledge of the neurobiological mechanisms underlying alcohol dependence.

This study has two main aims: i) to assess how eCB levels in different brain areas are modified by alcohol-induced conditioning place preference (CPP), and ii) to study how cannabinoid type 2 receptor (CB2R) is involved in alcohol-rewarding properties, using pharmacological manipulation in C57BL/6 mice.

Our results suggest that the eCB system is dysregulated throughout the mesocorticolimbic system by repeated alcohol exposure during the CPP paradigm, and that levels of anandamide (AEA) and several other N-acylethanolamines are markedly decreased in the medial prefrontal cortex and ventral midbrain of alcohol-CPP mice.

We also observed that the administering an antagonist/inverse agonist of the CB2R (AM630) during the acquisition phase of CPP reduced the rewarding effects of alcohol. However, activating CB2R signalling using the agonist JWH133 seems to reduce both alcohol- and food-rewarding behaviours. Therefore, our findings indicate that the rewarding effects of alcohol are related to its disruptive effect on AEA and other N-acylethanolamine signalling pathways.

Thus, pharmacological manipulation of CB2R is an interesting candidate treatment for alcohol use disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/31220547

https://www.sciencedirect.com/science/article/pii/S0091305719300656?via%3Dihub

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