Tag Archives: cannabinoid receptors

Relieving tension: effects of cannabinoids on vagal afferent sensitivity.

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Publication cover image“Endocannabinoids are produced within the gastrointestinal (GI) tract and modulate energy homeostasis and food intake, at least in part, via vagally-dependent actions. The recent paper by Christie et al., [Christie, et al. J Physiol, 2019] demonstrate, for the first time, that cannabinoids exert biphasic effects on the mechanosensitivity of tension-sensitive gastric vagal afferents. At higher concentrations, anandamide increased vagal afferent sensitivity in a CB1 and TRPV1 receptor dependent manner. At lower concentrations, however, anandamide decreased afferent mechanosensitivity; while this was also dependent upon CB1 and TRPV1 receptors, it also appeared dependent upon signaling via the potent orexigenic neurohormone, ghrelin. These results provide further evidence to support the remarkable degree of neuroplasticity within vagal afferent signaling, and suggest that untangling the complex interactions of cannabinoid effects on food intake and energy homeostasis will require careful physiological and pharmacological investigations.”

https://www.ncbi.nlm.nih.gov/pubmed/31707736

https://physoc.onlinelibrary.wiley.com/doi/abs/10.1113/JP279173

“A clear understanding of the mechanisms which mediate these events may provide novel therapeutic targets for the treatment of gastrointestinal disorders due to vago-vagal pathway malfunctions.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318799/

Cannabidiol increases the nociceptive threshold in a preclinical model of Parkinson’s disease.

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Neuropharmacology

“Medications that improve pain threshold can be useful in the pharmacotherapy of Parkinson’s disease (PD). Pain is a prevalent PD’s non-motor symptom with a higher prevalence of analgesic drugs prescription for patients. However, specific therapy for PD-related pain are not available.

Since the endocannabinoid system is expressed extensively in different levels of pain pathway, drugs designed to target this system have promising therapeutic potential in the modulation of pain. Thus, we examined the effects of the 6-hydroxydopamine- induced PD on nociceptive responses of mice and the influence of cannabidiol (CBD) on 6-hydroxydopamine-induced nociception.

Further, we investigated the pathway involved in the analgesic effect of the CBD through the co-administration with a fatty acid amide hydrolase (FAAH) inhibitor, increasing the endogenous anandamide levels, and possible targets from anandamide, i.e., the cannabinoid receptors subtype 1 and 2 (CB1 and CB2) and the transient receptor potential vanilloid type 1 (TRPV1).

We report that 6-hydroxydopamine- induced parkinsonism decreases the thermal and mechanical nociceptive threshold, whereas CBD (acute and chronic treatment) reduces this hyperalgesia and allodynia evoked by 6-hydroxydopamine. Moreover, ineffective doses of either FAAH inhibitor or TRPV1 receptor antagonist potentialized the CBD-evoked antinociception while an inverse agonist of the CB1 and CB2 receptor prevented the antinociceptive effect of the CBD.

Altogether, these results indicate that CBD can be a useful drug to prevent the parkinsonism-induced nociceptive threshold reduction. They also suggest that CB1 and TRPV1 receptors are important for CBD-induced analgesia and that CBD could produce these analgesic effects increasing endogenous anandamide levels.”

https://www.ncbi.nlm.nih.gov/pubmed/31706993

“The CBD treatment decreases hyperalgesia and allodynia in experimental parkinsonism.”

https://www.sciencedirect.com/science/article/pii/S0028390819303703?via%3Dihub

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Bone Anabolic Response in the Calvaria Following Mild Traumatic Brain Injury is Mediated by the Cannabinoid-1 Receptor.

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 Scientific Reports“Brain trauma was clinically associated with increased osteogenesis in the appendicular skeleton. We showed previously in C57BL/6J mice that mild traumatic brain injury (mTBI) transiently induced bone formation in the femur via the cannabinoid-1 (CB1) receptor. Here, we subjected ICR mice to mTBI and examined the bone response in the skull using microCT. We also measured mast cell degranulation (MCD)72 h post-injury. Finally, we measured brain and calvarial endocannabinoids levels post-mTBI. mTBI led to decreased bone porosity on the contralateral (untouched) side. This effect was apparent both in young and mature mice. Administration of rimonabant (CB1 inverse agonist) completely abrogated the effect of mTBI on calvarial porosity and significantly reduced MCD, compared with vehicle-treated controls. We also found that mTBI resulted in elevated levels of anandamide, but not 2-arachidonoylglycerol, in the contralateral calvarial bone, whereas brain levels remained unchanged. In C57BL/6J CB1 knockout mice, mTBI did not reduce porosity but in general the porosity was significantly lower than in WT controls. Our findings suggest that mTBI induces a strain-specific CB1-dependent bone anabolic response in the skull, probably mediated by anandamide, but seemingly unrelated to inflammation. The endocannabinoid system is therefore a plausible target in management of bone response following head trauma.”

https://www.ncbi.nlm.nih.gov/pubmed/31700010

https://www.nature.com/articles/s41598-019-51720-w

Inhibition of tremulous jaw movements in rats by memantine-Δ9 -tetrahydrocannabinol combination: neuroanatomical correlates.

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British Journal of Pharmacology banner“Memantine and marijuana smoking have been previously found to inhibit tremor in parkinsonian patients, however, the observed effects were relatively weak. The tremorolytic efficacy of memantine and cannabinoid co-administration is unstudied.

This work aimed to evaluate antitremor activity of memantine-Δ9 -tetrahydrocannabinol combination; additionally, the involvement of some neuroanatomical structures in the regulation of the combination effect was evaluated.

EXPERIMENTAL APPROACH:

Haloperidol-induced tremulous jaw movements in rats were used as a model of parkinsonian-like tremor. To evaluate the role of central receptor systems in the drug effect, receptor-targeting agents were administered locally into certain brain areas.

KEY RESULTS:

Memantine and Δ9 -tetrahydrocannabinol alone were without effect, however, co-administration of the drugs significantly decreased number of haloperidol-induced jaw movements. The antitremor activity of the combination was antagonized (i) by injections of L-glutamate into the dorsal striatum, entopeduncular nucleus, substantia nigra pars reticulata, globus pallidus, supratrigeminal and trigeminal motor nuclei but not into the subthalamic and cuneiform nuclei; (ii) by injections of CGS 21680 into the ventrolateral striatum; (iii) by injections of bicuculline into the rostral part of the parvicellular reticular nucleus.

CONCLUSION AND IMPLICATIONS:

Memantine and Δ9 -tetrahydrocannabinol supra-additively inhibit haloperidol-induced tremulous jaw movements. Apparently, the co-administration of the drugs might be a new approach to the treatment of tremor. The presented results identify brain areas influencing parkinsonian-like tremor in rats; these data can help advance the development of novel treatments for repetitive involuntary movements.”

https://www.ncbi.nlm.nih.gov/pubmed/31696510

https://bpspubs.onlinelibrary.wiley.com/doi/abs/10.1111/bph.14914

“Memantine is a prescription drug used to treat moderate to severe confusion (dementia) related to Alzheimer’s disease. Memantine is available under the following different brand names: Namenda XR, and Namenda.”  https://www.rxlist.com/consumer_memantine_namenda/drugs-condition.htm

The Expanded Endocannabinoid System/Endocannabinoidome as a Potential Target for Treating Diabetes Mellitus.

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 “The endocannabinoid (eCB) system, i.e. the receptors that respond to the psychoactive component of cannabis, their endogenous ligands and the ligand metabolic enzymes, is part of a larger family of lipid signals termed the endocannabinoidome (eCBome). We summarize recent discoveries of the roles that the eCBome plays within peripheral tissues in diabetes, and how it is being targeted, in an effort to develop novel therapeutics for the treatment of this increasingly prevalent disease.

RECENT FINDINGS:

As with the eCB system, many eCBome members regulate several physiological processes, including energy intake and storage, glucose and lipid metabolism and pancreatic health, which contribute to the development of type 2 diabetes (T2D). Preclinical studies increasingly support the notion that targeting the eCBome may beneficially affect T2D. The eCBome is implicated in T2D at several levels and in a variety of tissues, making this complex lipid signaling system a potential source of many potential therapeutics for the treatments for T2D.”

https://www.ncbi.nlm.nih.gov/pubmed/31686231

https://link.springer.com/article/10.1007%2Fs11892-019-1248-9

Anticancer effects of n-3 EPA and DHA and their endocannabinoid derivatives on breast cancer cell growth and invasion.

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Prostaglandins, Leukotrienes and Essential Fatty Acids Home“The anticancer effects of the omega-3 long chain polyunsaturated fatty acids (LCPUFA), EPA and DHA may be due, at least in part, to conversion to their respective endocannabinoid derivatives, eicosapentaenoyl-ethanolamine (EPEA) and docosahexaenoyl-ethanolamine (DHEA).

Here, the effects of EPEA and DHEA and their parent compounds, EPA and DHA, on breast cancer (BC) cell function was examined. EPEA and DHEA exhibited greater anti-cancer effects than EPA and DHA in two BC cells (MCF-7 and MDA-MB-231) whilst displaying no effect in non-malignant breast cells (MCF-10a).

Both BC lines expressed CB1/2 receptors that were responsible, at least partly, for the observed anti-proliferative effects of the omega-3 endocannabinoids as determined by receptor antagonism studies. Additionally, major signalling mechanisms elicited by these CB ligands included altered phosphorylation of p38-MAPK, JNK, and ERK proteins.

Both LCPUFAs and their endocannabinoids attenuated the expression of signal proteins in BC cells, albeit to different extents depending on cell type and lipid effectors. These signal proteins are implicated in apoptosis and attenuation of BC cell migration and invasiveness.

Furthermore, only DHA reduced in vitro MDA-MB-231 migration whereas both LCPUFAs and their endocannabinoids significantly inhibited invasiveness. This finding was consistent with reduced integrin β3 expression observed with all treatments and reduced MMP-1 and VEGF with DHA treatment.

Attenuation of cell viability, migration and invasion of malignant cells indicates a potential adjunct nutritional therapeutic use of these LCPUFAs and/or their endocannabinoids in treatment of breast cancer.”

https://www.ncbi.nlm.nih.gov/pubmed/31679810

https://www.plefa.com/article/S0952-3278(19)30112-7/fulltext

Targeting the cannabinoid receptor CB2 in a mouse model of l-dopa induced dyskinesia.

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Neurobiology of Disease“L-dopa induced dyskinesia (LID) is a debilitating side-effect of the primary treatment used in Parkinson’s disease (PD), l-dopa. Here we investigate the effect of HU-308, a cannabinoid CB2 receptor agonist, on LIDs.

Utilizing a mouse model of PD and LIDs, induced by 6-OHDA and subsequent l-dopa treatment, we show that HU-308 reduced LIDs as effectively as amantadine, the current frontline treatment. Furthermore, treatment with HU-308 plus amantadine resulted in a greater anti-dyskinetic effect than maximally achieved with HU-308 alone, potentially suggesting a synergistic effect of these two treatments. Lastly, we demonstrated that treatment with HU-308 and amantadine either alone, or in combination, decreased striatal neuroinflammation, a mechanism which has been suggested to contribute to LIDs.

Taken together, our results suggest pharmacological treatments with CB2 agonists merit further investigation as therapies for LIDs in PD patients. Furthermore, since CB2 receptors are thought to be primarily expressed on, and signal through, glia, our data provide weight to suggestion that neuroinflammation, or more specifically, altered glial function, plays a role in development of LIDs.”

https://www.ncbi.nlm.nih.gov/pubmed/31669673

“Collectively, our findings suggest CB2 agonists offer a putative target to treat LIDs, with efficacy comparable to the frontline treatment amantadine. Our study suggests that targeting glial function may be an important strategy for developing therapies for treating LIDs, a major unmet need for PD patients.”

https://www.sciencedirect.com/science/article/pii/S0969996119303213?via%3Dihub

Endocannabinoid System Alterations in Posttraumatic Stress Disorder: A Review of Developmental and Accumulative Effects of Trauma.

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 Image result for sage journals chronic stress“The role of the endocannabinoid system in stress-related psychiatric symptoms has been investigated in many animal and human studies.

Although most of these studies consistently report long-lasting effects of prolonged stress and trauma on the endocannabinoid system, the nature and direction of these changes are controversial.

We reviewed the available preclinical and clinical studies investigating the endocannabinoid system alterations long after chronic stress and trauma.

We propose that the effects of prolonged stress or trauma on the endocannabinoid system are different based on the developmental age of subjects at the time of experiencing the trauma and its repetitiveness and accumulative effects.

The current literature consistently demonstrates decreased levels of endocannabinoid ligands and receptors if the trauma occurs in childhood, whereas decreased levels of endocannabinoid ligands and increased levels of cannabinoid receptors are reported when trauma has happened in adulthood.

It is important to note that these changes are region-specific in the brain and also there are important sex differences, which are beyond the scope of this review.”

https://www.ncbi.nlm.nih.gov/pubmed/31660473

“More studies are needed to compare the effects of childhood and adulthood trauma, with or without PTSD presentations, on the eCB system. These studies would have important clinical implications, not only for individuals with trauma and PTSD who commonly have comorbid recreational cannabis use, and medical marijuana users with PTSD being one of its main indicators but also for studies investigating the potential therapeutic use of cannabinoids and eCB enhancers in PTSD treatment.”

https://journals.sagepub.com/doi/10.1177/2470547019864096

Structure of an allosteric modulator bound to the CB1 cannabinoid receptor.

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Image result for nature chemical biology“The CB1 receptor mediates the central nervous system response to cannabinoids, and is a drug target for pain, anxiety and seizures.

CB1 also responds to allosteric modulators, which influence cannabinoid binding and efficacy.

To understand the mechanism of these compounds, we solved the crystal structure of CB1 with the negative allosteric modulator (NAM) ORG27569 and the agonist CP55940.

The structure reveals that the NAM binds to an extrahelical site within the inner leaflet of the membrane, which overlaps with a conserved site of cholesterol interaction in many G protein-coupled receptors (GPCRs).

The ternary structure with ORG27569 and CP55940 captures an intermediate state of the receptor, in which aromatic residues at the base of the agonist-binding pocket adopt an inactive conformation despite the large contraction of the orthosteric pocket.

The structure illustrates a potential strategy for drug modulation of CB1 and other class A GPCRs.”

https://www.ncbi.nlm.nih.gov/pubmed/31659318

https://www.nature.com/articles/s41589-019-0387-2

Cannabinoid receptor 2‑selective agonist JWH015 attenuates bone cancer pain through the amelioration of impaired autophagy flux induced by inflammatory mediators in the spinal cord.

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Journal Cover “Bone cancer pain (BCP) is a severe complication of advanced bone cancer.

Although cannabinoid receptor 2 (CB2) agonists may have an analgesic effect, the underlying mechanism remains unclear.

CB2 serves a protective role in various pathological states through the activation of autophagy. Therefore, the present study aimed to determine whether the analgesic effects of the selective CB2 agonist JWH015 was mediated by the activation of autophagy in BCP.

The results of the present study suggested that the impairment of autophagy flux was induced by glia‑derived inflammatory mediators in spinal neurons. Intrathecal administration of the selective CB2 agonist JWH015 ameliorated autophagy flux through the downregulation of IL‑1β and IL‑6 and attenuated BCP.”

https://www.ncbi.nlm.nih.gov/pubmed/31661120

https://www.spandidos-publications.com/10.3892/mmr.2019.10772