Tag Archives: cannabinoid receptors

Endocannabinoid mechanism in amphetamine-type stimulant use disorders: A short review.

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Journal of Clinical Neuroscience Home

“Recent evidence shows that the endocannabinoid system is involved in amphetamine-type stimulants (ATS) use disorders. To elucidate the role of the endocannabinoid system in ATS addiction, we reviewed results of studies using cannabinoid receptor agonists, antagonists as well as knockout model.

The endocannabinoid system seems to play a role in reinstatement and relapse of ATS addiction and ATS-induced psychiatric symptoms. The molecular mechanisms of this system remains unclear, the association with dopamine system in nucleus accumbens is most likely involved. However, the function of the endocannabinoid system in anxiety and anti-anxiety effects induced by ATS is more complicated.

These findings suggest that the endocannabinoid system may play an important role in the mechanism of ATS addiction and provide new idea for treating ATS addiction.”

https://www.ncbi.nlm.nih.gov/pubmed/28912087

http://www.jocn-journal.com/article/S0967-5868(17)30989-X/fulltext

The role of cannabinoid receptors in renal diseases.

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“Chronic kidney disease (CKD) remains a major challenge for Public Health systems and corresponds to the replacement of renal functional tissue by extra-cellular matrix proteins such as collagens and fibronectin. There is no efficient treatment to date for CKD except nephroprotective strategies.

The cannabinoid system and more specifically the cannabinoid receptors 1 (CB1) and 2 (CB2) may represent a new therapeutic target in CKD.

Our review will first focus on the current state of knowledge regarding the cannabinoid system in normal renal physiology and in various experimental nephropathies, especially diabetes.  We will review the data obtained in models of diabetes and obesity as well as in nonmetabolic models of renal fibrosis and emphasizes the promising role of CB1 blockers and CB2 agonists in the development of renal disease and fibrosis. Next, we will review the current state of knowledge regarding the cellular pathways involved in renal fibrogenesis and renal injury.

Overall, this review will highlight the therapeutic potential of targeting the cannabinoid receptors in CKD and diabetes.”

https://www.ncbi.nlm.nih.gov/pubmed/28901271

Polymorphism rs3123554 in the cannabinoid receptor gene type 2 (CNR2) reveals effects on body weight and insulin resistance in obese subjects.

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Endocrinología, Diabetes y Nutrición

“Few studies assessing the relationship between single nucleotide polymorphisms in CNR2 and obesity or its related metabolic parameters are available.

OBJECTIVE:

To investigate the influence of polymorphism rs3123554 in the CNR2 receptor gene on obesity anthropometric parameters, insulin resistance, and adipokines in subjects with obesity.

DESIGN:

The study population consisted of 1027 obese subjects, who were performed bioelectrical impedance analyses, blood pressure measurements, serial assessments of dietary intake during three days, and biochemical tests.

RESULTS:

Genotypes GG, GA, and AA were found in 339 (33.0%), 467 (45.5%), and 221 (21.5%) respectively. Body mass index, weight, fat mass, waist circumference, insulin, HOMA-IR, and triglyceride and leptin levels were higher in A-allele carriers as compared to non A-allele carriers. No differences were seen in these parameters between the GA and AA genotypes. There were no statistical differences in dietary intake.

CONCLUSION:

The main study finding was the association of the minor allele of the SNP rs3123554 in the CNR2 gene with body weight and triglyceride, HOMA-IR, insulin, and leptin levels.”

https://www.ncbi.nlm.nih.gov/pubmed/28895540

http://www.sciencedirect.com/science/article/pii/S2530016417301799?via%3Dihub

Activation of dorsal horn cannabinoid CB2 receptor suppresses the expression of P2Y12 and P2Y13 receptors in neuropathic pain rats.

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“More evidence suggests that dorsal spinal cord microglia is an important site contributing to CB2 receptor-mediated analgesia. The upregulation of P2Y12 and P2Y13 purinoceptors in spinal dorsal horn microglia is involved in the development of pain behavior caused by peripheral nerve injury. However, it is not known whether the expression of P2Y12 and P2Y13 receptors at spinal dorsal horn will be influenced after CB2 receptor activation in neuropathic pain rats. Chronic constriction injury (CCI) and intrathecal ADPbetaS injection were performed in rats to induce neuropathic pain.

In CCI- and ADPbetaS-treated rats, AM1241 pretreatment could efficiently activate CB2 receptor, while inhibiting p38MAPK and NF-kappaB activation in the dorsal spinal cord. CB2 receptor stimulation decreased P2Y13 receptor expression via p38MAPK/NF-kappaB signaling. On the other hand, CB2 receptor activation decreased P2Y12 receptor expression via p38MAPK-independent NF-kappaB signaling pathway.”

https://www.ncbi.nlm.nih.gov/pubmed/28899427

 https://jneuroinflammation.biomedcentral.com/articles/10.1186/s12974-017-0960-0

Effects of coadministration of low dose cannabinoid type 2 receptor agonist and morphine on vanilloid receptor 1 expression in a rat model of cancer pain.

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“Morphine is widely used as an analgesic to treat moderate to severe pain, but chronic morphine use is associated with development of tolerance and dependence, which limits its analgesic efficacy. Our previous research has showed that nonanalgetic dose of a cannabinoid type 2 (CB2) receptor agonist reduced morphine tolerance in cancer pain. A previous study showed the colocalization of CB2 and transient receptor potential vanilloid 1 (TRPV1) in human and rat dorsal root ganglia (DRG) sensory neurons. Whether coadministration of a CB2 receptor agonist and morphine could reduce TRPV1 expression in morphine‑induced antinociception and tolerance in cancer pain is unclear. Therefore, we investigated the effects of coadministration of a CB2 receptor agonist AM1241 and morphine on TRPV1 expression and tolerance in cancer pain. Coadministration of AM1241 and morphine for 8 days significantly reduced morphine tolerance, as assessed by measuring paw withdrawal latency to a radiant heat stimulation, in Walker 256 tumor‑bearing rats. Repeated morphine treatment for a period of 8 days induced upregulation of the TRPV1 protein expression levels in the DRG in the tumor‑bearing rats, although no change in mRNA expression. Pretreatment with AM1241 reduced this morphine‑induced upregulation of TRPV1 and the effect was reversed by the CB2 receptor antagonist AM630. Our findings suggest that coadministration of a CB2 receptor agonist AM1241 and morphine reduced morphine tolerance possibly through regulation of TRPV1 protein expression in the DRG in cancer pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28901432

https://www.spandidos-publications.com/10.3892/mmr.2017.7479

Tingenone, a pentacyclic triterpene, induces peripheral antinociception due to cannabinoid receptors activation in mice.

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“Several works have shown that triterpenes induce peripheral antinociception by activation of cannabinoid receptors and endocannabinoids; besides, several research groups have reported activation of cannabinoid receptors in peripheral antinociception.

The aim of this study was to assess the involvement of the cannabinoid system in the antinociceptive effect induced by tingenone against hyperalgesia evoked by prostaglandin E2 (PGE2) at peripheral level.

The results suggest that tingenone induced a peripheral antinociceptive effect via cannabinoidreceptor activation. Therefore, this study suggests a pharmacological potential for a new analgesic drug.”

https://www.ncbi.nlm.nih.gov/pubmed/28889355

Distinct roles of neuronal and microglial CB2 cannabinoid receptors in the mouse hippocampus.

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“The effects of cannabinoids are primarily mediated by type-1 cannabinoid receptors in the brain and type-2 cannabinoid receptors (CB2Rs) in the peripheral immune system. However, recent evidence demonstrates that CB2Rs are also expressed in the brain and implicated in neuropsychiatric effects. Diverse types of cells in various regions in the brain express CB2Rs but the cellular loci of CB2Rs that induce specific behavioral effects have not been determined. To manipulate CB2R expression in specific types of cells in the dorsal hippocampus of adult mice, we used Cre-dependent overexpression and CRISPR-Cas9 genome editing techniques in combination with adeno-associated viruses and transgenic mice. Elevation and disruption of CB2R expression in microglia in the CA1 area increased and decreased, respectively, contextual fear memory. In CA1 pyramidal neurons, disruption of CB2R expression enhanced spatial working memory, whereas their overexpression reduced anxiety levels assessed as an increase in the exploration time in the central area of open field. Interneuronal CB2Rs were not involved in the modulation of cognitive or emotional behaviors tested in this study. The targeted manipulation of CB2R expression in pyramidal neurons and microglia suggests that CB2Rs in different types of cells in the mature hippocampus play distinct roles in the regulation of memory and anxiety.”

https://www.ncbi.nlm.nih.gov/pubmed/28888955

http://www.sciencedirect.com/science/article/pii/S0306452217306292

Anti-nociceptive interactions between opioids and a cannabinoid receptor 2 agonist in inflammatory pain.

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SAGE Journals

“The cannabinoid 1 receptor and cannabinoid 2 receptor can both be targeted in the treatment of pain; yet, they have some important differences. Cannabinoid 1 receptor is expressed at high levels in the central nervous system, whereas cannabinoid 2 receptor is found predominantly, although not exclusively, outside the central nervous system. The objective of this study was to investigate potential interactions between cannabinoid 2 receptor and the mu-opioid receptor in pathological pain. The low level of adverse side effects and lack of tolerance for cannabinoid 2 receptor agonists are attractive pharmacotherapeutic traits. This study assessed the anti-nociceptive effects of a selective cannabinoid 2 receptor agonist (JWH-133) in pathological pain using mice subjected to inflammatory pain using the formalin test. Furthermore, we examined several ways in which JWH-133 may interact with morphine. JWH-133 produces dose-dependent anti-nociception during both the acute and inflammatory phases of the formalin test. This was observed in both male and female mice. However, a maximally efficacious dose of JWH-133 (1 mg/kg) was not associated with somatic withdrawal symptoms, motor impairment, or hypothermia. After eleven once-daily injections of 1 mg/JWH-133, no tolerance was observed in the formalin test. Cross-tolerance for the anti-nociceptive effects of JWH-133 and morphine were assessed to gain insight into physiologically relevant cannabinoid 2 receptor and mu-opioid receptor interaction. Mice made tolerant to the effects of morphine exhibited a lower JWH-133 response in both phases of the formalin test compared to vehicle-treated morphine-naïve animals. However, repeated daily JWH-133 administration did not cause cross-tolerance for morphine, suggesting opioid and cannabinoid 2 receptor cross-tolerance is unidirectional. However, preliminary data suggest co-administration of JWH-133 with morphine modestly attenuates morphine tolerance. Isobolographic analysis revealed that co-administration of JWH-133 and morphine has an additive effect on anti-nociception in the formalin test. Overall these findings show that cannabinoid 2 receptor may functionally interact with mu-opioid receptor to modulate anti-nociception in the formalin test.”

https://www.ncbi.nlm.nih.gov/pubmed/28879802

http://journals.sagepub.com/doi/10.1177/1744806917728227

 

G protein-coupled receptor GPR55 promotes colorectal cancer and has opposing effects to cannabinoid receptor 1.

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International Journal of Cancer

“The putative cannabinoid receptor GPR55 has been shown to play a tumor-promoting role in various cancers, and is involved in many physiological and pathological processes of the gastrointestinal (GI) tract.

While the cannabinoid receptor 1 (CB1 ) has been reported to suppress intestinal tumor growth, the role of GPR55 in the development of GI cancers is unclear. We, therefore, aimed at elucidating the role of GPR55 in colorectal cancer (CRC), the third most common cancer worldwide.

Collectively, our data suggest that GPR55 and CB1 play differential roles in colon carcinogenesis where the former seems to act as oncogene and the latter as tumor suppressor.”

https://www.ncbi.nlm.nih.gov/pubmed/28875496

http://onlinelibrary.wiley.com/doi/10.1002/ijc.31030/abstract

Interplay Between n-3 and n-6 Long-Chain Polyunsaturated Fatty Acids and the Endocannabinoid System in Brain Protection and Repair.

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 Lipids

“The brain is enriched in arachidonic acid (ARA) and docosahexaenoic acid (DHA), long-chain polyunsaturated fatty acids (LCPUFAs) of the n-6 and n-3 series, respectively. Both are essential for optimal brain development and function. Dietary enrichment with DHA and other long-chain n-3 PUFA, such as eicosapentaenoic acid (EPA), has shown beneficial effects on learning and memory, neuroinflammatory processes, and synaptic plasticity and neurogenesis. ARA, DHA and EPA are precursors to a diverse repertoire of bioactive lipid mediators, including endocannabinoids.

The endocannabinoid system comprises cannabinoid receptors, their endogenous ligands, the endocannabinoids, and their biosynthetic and degradation enzymes. Anandamide (AEA) and 2-arachidonoylglycerol (2-AG) are the most widely studied endocannabinoids and are both derived from phospholipid-bound ARA. The endocannabinoid system also has well-established roles in neuroinflammation, synaptic plasticity and neurogenesis, suggesting an overlap in the neuroprotective effects observed with these different classes of lipids.

Indeed, growing evidence suggests a complex interplay between n-3 and n-6 LCPUFA and the endocannabinoid system. For example, long-term DHA and EPA supplementation reduces AEA and 2-AG levels, with reciprocal increases in levels of the analogous endocannabinoid-like DHA and EPA-derived molecules. This review summarises current evidence of this interplay and discusses the therapeutic potential for brain protection and repair.”

https://www.ncbi.nlm.nih.gov/pubmed/28875399

https://link.springer.com/article/10.1007%2Fs11745-017-4292-8

“The seed of Cannabis sativa L. has been an important source of nutrition for thousands of years in Old World cultures. Technically a nut, hempseed typically contains over 30% oil and about 25% protein, with considerable amounts of dietary fiber, vitamins and minerals. Hempseed oil is over 80% in polyunsaturated fatty acids (PUFAs), and is an exceptionally rich source of the two essential fatty acids (EFAs) linoleic acid (18:2 omega-6) and alpha-linolenic acid (18:3 omega-3). The omega-6 to omega-3 ratio (n6/n3) in hempseed oil is normally between 2:1 and 3:1, which is considered to be optimal for human health. Hempseed has been used to treat various disorders for thousands of years in traditional oriental medicine.”  http://link.springer.com/article/10.1007%2Fs10681-004-4811-6