Tag Archives: cannabinoid receptors

Autophagy activation by novel inducers prevents BECN2-mediated drug tolerance to cannabinoids.

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“Cannabinoids and related drugs generate profound behavioral effects (such as analgesic effects) through activating CNR1 (cannabinoid receptor 1 [brain]). However, repeated cannabinoid administration triggers lysosomal degradation of the receptor and rapid development of drug tolerance, limiting the medical use of marijuana in chronic diseases.

Here we show that a protein involved in macroautophagy/autophagy (a conserved lysosomal degradation pathway), BECN2 (beclin 2), mediates cannabinoid tolerance by preventing CNR1 recycling and resensitization after prolonged agonist exposure, and deletion of Becn2 rescues CNR1 activity in mouse brain and conveys resistance to analgesic tolerance to chronic cannabinoids.

Overall, our findings demonstrate the functional link among autophagy, receptor signaling and animal behavior regulated by psychoactive drugs, and develop a new strategy to prevent tolerance and improve medical efficacy of cannabinoids by modulating the BECN2 interactome and autophagy activity.”

http://www.ncbi.nlm.nih.gov/pubmed/27305347

CB2 Cannabinoid Receptor As Potential Target against Alzheimer’s Disease.

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“The CB2 receptor is one of the components of the endogenous cannabinoid system, a complex network of signaling molecules and receptors involved in the homeostatic control of several physiological functions. Accumulated evidence suggests a role for CB2 receptors in Alzheimer’s disease (AD) and indicates their potential as a therapeutic target against this neurodegenerative disease.

Levels of CB2 receptors are significantly increased in post-mortem AD brains, mainly in microglia surrounding senile plaques, and their expression levels correlate with the amounts of Aβ42 and β-amyloid plaque deposition.

Moreover, several studies on animal models of AD have demonstrated that specific CB2 receptor agonists, which are devoid of psychoactive effects, reduce AD-like pathology, resulting in attenuation of the inflammation associated with the disease but also modulating Aβ and tau aberrant processing, among other effects.

CB2 receptor activation also improves cognitive impairment in animal models of AD.

This review discusses available data regarding the role of CB2 receptors in AD and the potential usefulness of specific agonists of these receptors against AD.”

http://www.ncbi.nlm.nih.gov/pubmed/27303261

Modulation of cannabinoid signaling by hippocampal 5-HT4 serotonergic system in fear conditioning.

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“Behavioral studies have suggested a key role for the cannabinoid system in the modulation of conditioned fear memory. Likewise, much of the literature has revealed that the serotonergic system affects Pavlovian fear conditioning and extinction. A high level of functional overlap between the serotonin and cannabinoid systems has also been reported.

To clarify the interaction between the hippocampal serotonin (5-HT4) receptor and the cannabinoid CB1 receptor in the acquisition of fear memory, the effects of 5-HT4 agents, arachidonylcyclopropylamide (ACPA; CB1 receptor agonist), and the combined use of these drugs on fear learning were studied in a fear conditioning task in adult male NMRI mice.

Pre-training intraperitoneal administration of ACPA (0.1 mg/kg) decreased the percentage of freezing time in both context- and tone-dependent fear conditions, suggesting impairment of the acquisition of fear memory. Pre-training, intra-hippocampal (CA1) microinjection of RS67333, a 5-HT4 receptor agonist, at doses of 0.1 and 0.2 or 0.2 µg/mouse impaired contextual and tone fear memory, respectively. A subthreshold dose of RS67333 (0.005 µg/mouse) did not alter the ACPA response in either condition.

Moreover, intra-CA1 microinjection of RS23597 as a 5-HT4 receptor antagonist did not alter context-dependent fear memory acquisition, but it did impair tone-dependent fear memory acquisition. However, a subthreshold dose of the RS23597 (0.01 µg/mouse) potentiated ACPA-induced fear memory impairment in both conditions.

Therefore, we suggest that the blockade of hippocampal 5-HT4 serotonergic system modulates cannabinoid signaling induced by the activation of CB1 receptors in conditioned fear.”

http://www.ncbi.nlm.nih.gov/pubmed/27296273

Cannabinoid receptor 2 as anti-obesity target: inflammation, fat storage and browning modulation.

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“Obesity is associated with a low-grade inflammatory state, and adipocyte hyperplasia/hypertrophy.

Obesity inhibits the “browning” of white adipose tissue.

Cannabinoid receptor 2 (CB2) agonists reduce food intake and induce anti-obesity effect in mice.

CB2 receptor is a novel pharmacological target that should be considered for obesity.”

http://www.ncbi.nlm.nih.gov/pubmed/27294325

http://www.thctotalhealthcare.com/category/obesity-2/

Cannabinoids cool the intestine

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“Inflammatory bowel diseases (IBDs) such as ulcerative colitis and Crohn’s disease affects over a million people in the United States, with an estimated indirect cost from work loss of $3.6 billion annually. Many of these individuals suffer from pain, diarrhea and poor ability to digest their food, and in up to half of those with IBD, the disease is so severe that it ultimately requires surgery to remove the affected bowel segment.

Historically, marijuana has been used to treat diarrhea and has been advocated for the treatment of a variety of other gastrointestinal problems, including Crohn’s disease.

More recent pharmacological studies have clearly established that cannabinoids inhibit gastrointestinal motility and secretion by acting on CB1 receptors located on the terminals of both intrinsic and extrinsic submucosal neurons.

When administered to mice with chemically induced enteritis, cannabinoids also reduce inflammation and fluid accumulation in the gut.

Cannabinoids inhibit motility and secretion in the intestine.

They are now assigned the additional task of curbing excessive inflammation, suggesting that drugs targeting the endogenous cannabinoid system could be exploited for inflammatory bowel disease.

These findings may offer a new therapeutic approach to IBD.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2516444/

 

CANNABIS CHEMICALS STOP PROSTATE CANCER GROWTH

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“ACTIVE chemicals in cannabis have been shown to halt prostate cancer cell growth according to research published in the British Journal of Cancer*.

Researchers from the University of Alcala, in Madrid tested the effects of the active chemicals in cannabis called cannabinoids** on three human prostate cancer cell lines – called PC-3, DU-a45 and LNCaP.

The prostate cancer cells carry molecular ‘garages’- called receptors- in which cannabinoids can ‘park’.

The scientists showed for the first time that if cannabinoids ‘park’ on a receptor called CB2, the cancer cells stop multipyling.

“This research suggest that prostate cancer cells might stop growing if they are treated with chemicals found in cannabis but more work needs to be done to explore the potential of the cannabinoids in treatment.”

To confirm the findings the scientists switched off the CB2 receptors – or ‘closed the garage doors’- on the prostate cells. When cannabinoids were then added to cells without the CB2 receptor, the prostate cancer cells carried on dividing and growing. This suggests that cannabinoids connect with the CB2 receptors on prostate cancer cells to stop cell division and spread.

Professor Ines Diaz-Laviada, study author at the University of Alcala said: “Our research shows that there are areas on prostate cancer cells which can recognise and talk to chemicals found in cannabis called cannabinoids. These chemicals can stop the division and growth of prostate cancer cells and could become a target for new research into potential drugs to treat prostate cancer.””

http://www.nature.com/bjc/press_releases/p_r_aug09_6605248.html

https://www.news-medical.net/news/20090821/Cannabis-chemicals-stop-prostate-cancer-growth.aspx

Inhibition of human tumour prostate PC-3 cell growth by cannabinoids R(+)-Methanandamide and JWH-015: Involvement of CB2

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“We have previously shown that cannabinoids induce growth inhibition and apoptosis in prostate cancer PC-3 cells, which express high levels of cannabinoid receptor types 1 and 2 (CB1 and CB2). In this study, we investigated the role of CB2 receptor in the anti-proliferative action of cannabinoids and the signal transduction triggered by receptor ligation.

This study defines the involvement of CB2-mediated signalling in the in vivo and in vitro growth inhibition of prostate cancer cells and suggests that CB2 agonists have potential therapeutic interest and deserve to be explored in the management of prostate cancer.

Cannabinoids, the active components of Cannabis sativa and their derivatives, exert a wide spectrum of modulatory actions and pharmacological activities in the brain as well as in the periphery, and therefore, the therapeutic potential of cannabinoids has gained much attention during the past few years. One of the most exciting areas of current research in the therapeutic potential of cannabinoids is cancer.

Recent evidence suggests that cannabinoids are powerful regulators of cell growth and differentiation. They have been shown to exert anti-tumoural effects by decreasing viability, proliferation, adhesion and migration on various cancer cells, thereby suggesting the potential use of cannabinoids in the treatment of gliomas, prostate and breast cancers and malignancies of immune origin.

Overall, our data show a role for the cannabinoid receptor CB2 in the anti-tumour effect of cannabinoids on prostate cells in vitroand in vivo. There is considerable interest in the application of selective CB2 receptor agonists, which are devoid of typical marijuana-like psychoactive properties of CB1 agonists, for future cannabinoid-based anticancer therapies. Therefore, our findings point to the potential application of cannabinoid receptor type 2 ligands as anti-tumour agents in prostate cancer.”

 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743360/
http://www.thctotalhealthcare.com/category/prostate-cancer/

Current Status and Prospects for Cannabidiol Preparations as New Therapeutic Agents.

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“There is growing pressure for states and the federal government to legalize the use of cannabis products for medical purposes in the United States.

Sixteen states have legalized (or decriminalized possession of) products high in cannabidiol (CBD) and with restricted Δ9 -tetrahydrocannabinol (Δ9 -THC) content. In most of these states, the intent is for use in refractory epileptic seizures in children, but in a few states, the indications are broader.

The objectives of this review are to provide an overview of the pharmacology and toxicology of CBD; to summarize some of the regulatory, safety, and cultural issues relevant to the further exploitation of its antiepileptic or other pharmacologic activities; and to assess the current status and prospects for clinical development of CBD and CBD-rich preparations for medical use in the United States.

Unlike Δ9 -THC, CBD elicits its pharmacologic effects without exerting any significant intrinsic activity on the cannabinoid receptors (CB1 and CB2 ), whose activation results in the psychotropic effects characteristic of Δ9 -THC, and CBD possesses several pharmacologic activities that give it a high potential for therapeutic use.

CBD exhibits antiepileptic, anxiolytic, antipsychotic, and antiinflammatory properties.

In combination with Δ9 -THC, CBD has received regulatory approvals in several European countries and is currently under study in U.S. Food and Drug Administration-registered trials in the United States.

A number of states have passed legislation to allow for the use of CBD-rich, limited Δ9 -THC-content preparations of cannabis for certain pathologic conditions. CBD is currently being studied in several clinical trials and is at different stages of clinical development for various medical indications.

Judging from clinical findings reported so far, CBD and CBD-enriched preparations have great potential utility, but uncertainties regarding sourcing, long-term safety, abuse potential, and regulatory dilemmas remain.”

http://www.ncbi.nlm.nih.gov/pubmed/27285147

Activation of cannabinoid CB1 receptors in the ventral hippocampus improved stress-induced amnesia in rat.

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“The ventral hippocampus (VH) has a high distribution of cannabinoid CB1 receptors which are important in modulating stress responses. Stress exposure activates the hypothalamic-pituitary-adrenal axis (HPA) which can impact hippocampal formation to change hippocampus-based memories.

The purpose of the present study was to determine the possible role of the VH cannabinoid CB1 receptors in stress-induced amnesia using a step-through passive avoidance procedure in male Wistar rats.

Taken together, it can be concluded that exposure to post-training inescapable stress impaired memory consolidation. The impairing effects of stress on memory retrieval may be mediated by the VH cannabinoid CB1 receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27282634

The effect of spinally administered WIN 55,212-2, a cannabinoid agonist, on thermal pain sensitivity in diabetic rats.

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“These data show that cannabinoids have potent antinociceptive effects through direct actions in the spinal dorsal horn of nociceptive pathway. This suggests that intrathecally administered cannabinoids may offer hopeful strategies for the treatment of diabetic neuropathic pain.”

http://www.ncbi.nlm.nih.gov/pubmed/27279983