[Progress in study on endocannabinoids and cannabinoid receptors in the treatment for neuropathic pain].

 

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“Endocannabinoids and cannabinoid receptors are expressed in various central pain modulation regions. They maintain in dynamic changes in the expression level and distribution under different pathological and physiological conditions. These changes possess advantage as well as disadvantage. Exogenous administration of endocannabinoids exerts analgesic effect in different pain models, which is mainly mediated by the cannabinoid CB1 and CB2 receptors. Inhibition of enzymes for degrading endocannabinoids in different pain models also shows analgesic effect due to the increased local levels of endocannabinoids.”

Selective modulator of cannabinoid receptor type 2 (CB2) against biochemical alterations and brain damage in chronic cerebral hypoperfusion induced vascular dementia.

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“Vascular dementia is the second most common cause of cognitive decline in aged people but the effectual therapeutic target is still missing.

Chronic cerebral hypoperfusion (CCH) has been widely found in vascular dementia (VaD) patients. CCH is thought to link with neurodegenerative disorders and their subsequent cognitive impairment.

The present study has been framed to investigate the role of selective agonist of CB2 receptor (1-phenylisatin) in CCH induced VaD.

These results indicate that 2VO induced CCH in rats, which was attenuated with the treatment of 1-phenylisatin.

Hence, it may be suggested that modulation in cannabinoid receptor may provide benefits in CCH as cognitive impairment and VaD.

Therefore, pharmacological positive modulation of CB2 receptors may be a potential research target for alleviation of VaD.”

http://www.ncbi.nlm.nih.gov/pubmed/27599483

Interaction between Cannabinoid System and Toll-Like Receptors Controls Inflammation.

 

 

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“Since the discovery of the endocannabinoid system consisting of cannabinoid receptors, endogenous ligands, and biosynthetic and metabolizing enzymes, interest has been renewed in investigating the promise of cannabinoids as therapeutic agents.

Abundant evidence indicates that cannabinoids modulate immune responses.

An inflammatory response is triggered when innate immune cells receive a danger signal provided by pathogen- or damage-associated molecular patterns engaging pattern-recognition receptors.

Toll-like receptor family members are prominent pattern-recognition receptors expressed on innate immune cells.

Cannabinoids suppress Toll-like receptor-mediated inflammatory responses.

Innate immune cells express cannabinoid receptors and produce endogenous cannabinoids.

Hence, innate immune cells may play a role in regulating endocannabinoid homeostasis, and, in turn, the endocannabinoid system modulates local inflammatory responses.

Studies designed to probe the interaction between the innate immune system and the endocannabinoid system may identify new potential molecular targets in developing therapeutic strategies for chronic inflammatory diseases.

This review discusses the endocannabinoid system and Toll-like receptor family and evaluates the interaction between them.”

http://www.ncbi.nlm.nih.gov/pubmed/27597805

Cell type-specific tandem affinity purification of the mouse hippocampal CB1 receptor-associated proteome.

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“G protein coupled receptors (GPCR’s) exert their effects through multiprotein signaling complexes. The cannabinoid receptor type 1 (CB1) is among the most abundant GPCR’s in the mammalian brain and involved in a plethora of physiological functions. We used a combination of viral-mediated cell type-specific expression of a tagged CB1 fusion protein (CB1-SF), tandem affinity purification (TAP) and proteomics on hippocampal mouse tissue to analyze the composition and differences of CB1 protein complexes in glutamatergic neurons and in GABAergic interneurons. Purified proteins underwent tryptic digestion and were identified using deep-coverage data-independent acquisition with ion mobility separation-enhanced mass spectroscopy, leading to the identification of 951 proteins specifically enriched in glutamatergic and GABAergic CB1-SF TAP samples as compared to controls. Gene Ontology and protein network analyses showed an enrichment of single proteins and functional clusters of proteins involved in already well described domains of CB1 functions. Supported by this consistent dataset we could confirm already known CB1 interactors, reveal new potentially interacting proteins and differences in cell type-specific signaling properties of CB1, thereby providing the foundation for further functional studies on differential CB1 signaling.”

http://www.ncbi.nlm.nih.gov/pubmed/27596989

2-Arachidonylglycerol, an endogenous cannabinoid, inhibits tumor necrosis factor-alpha production in murine macrophages, and in mice.

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“2-Arachidonylglycerol (2-AG) inhibits the production in vitro of tumor necrosis factor-alpha (TNF-alpha) by mouse macrophages, as well as in mice. It has no effect on the production of nitric oxide (NO). The effect on TNF-alpha is enhanced when 2-AG is administered together with 2-linoleylglycerol (2-Lino-G) and 2-palmitylglycerol (2-PalmG), an ‘entourage effect’ previously noted in several behavioral and binding assays. 2-AG also suppresses the formation of radical oxygen intermediates.”

Dorsal hippocampus cannabinoid type 1 receptors modulate the expression of contextual fear conditioning in rats: Involvement of local glutamatergic/nitrergic and GABAergic neurotransmissions.

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“The cannabinoid receptor type 1 (CB1) is highly expressed in the dorsal portion of hippocampus – a brain region that has been involved in the control of conditioned emotional response (CER) in the contextual fear conditioning (CFC) model.

These responses are characterized by increased freezing behavior and autonomic parameters. Moreover, CB1 receptors activation negatively modulate the release of several neurotransmitters, including glutamate and GABA, which also have been related to modulation of CER. Therefore, our aim was to investigate the involvement of CB1 receptors in the dorsal hippocampus on CER expression.

Our results suggest that increased CER evoked by CB1 blockade in the dorsal hippocampus depends on NMDA receptor activation and NO formation. Moreover, a fine-tune control promoted by GABAergic and glutamatergic mechanisms in this brain area modulate the CER after CB1 blockade.”

http://www.ncbi.nlm.nih.gov/pubmed/27591981

Characterization of peripheral cannabinoid receptor expression and clinical correlates in schizophrenia.

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“The relationship between cannabinoid receptor signaling and psychosis vulnerability requires further exploration.

The endocannabinoid signaling system is extensive, with receptors exerting regulatory functions in both immune and central nervous systems.

In the brain, cannabinoid receptors (CBR) directly modulate neurotransmitter systems.

In the peripheral lymphocyte, CBRs mediate cytokine release, with dysregulated cytokine levels demonstrated in schizophrenia.

These results continue to support dysregulation of particular aspects of the endocannabinoid signaling system in participants with schizophrenia selected for the self-reported absence of marijuana abuse/dependence.”

http://www.ncbi.nlm.nih.gov/pubmed/27591408

Interaction between interleukin-1β and type-1 cannabinoid receptor is involved in anxiety-like behavior in experimental autoimmune encephalomyelitis.

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“Mood disorders, including anxiety and depression, are frequently diagnosed in multiple sclerosis (MS) patients, even independently of the disabling symptoms associated with the disease.

Anatomical, biochemical, and pharmacological evidence indicates that type-1 cannabinoid receptor (CB1R) is implicated in the control of emotional behavior and is modulated during inflammatory neurodegenerative diseases such as MS and experimental autoimmune encephalomyelitis (EAE).

We investigated whether CB1R could exert a role in anxiety-like behavior in mice with EAE. We performed behavioral, pharmacological, and electrophysiological experiments to explore the link between central inflammation, mood, and CB1R function in EAE.

Overall, results of the present investigation indicate that synaptic dysfunction linked to CB1R is involved in EAE-related anxiety and motivation-based behavior and contribute to clarify the complex neurobiological mechanisms underlying mood disorders associated to MS.

Collectively, our data contribute to clarify the synaptic and, at least in part, molecular basis of mood disturbances in EAE and, possibly, MS. Understanding the neurobiological underpinning of anxiety-like behavior in EAE mice is of crucial importance to optimize the treatment of mood disturbance in MS and, possibly, other neuroinflammatory diseases.

In this direction, targeting the endocannabinoid system may be a valid therapeutic tool for the treatment of both psychiatric and motor symptoms in MS patients.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5009553/

Possible Therapeutic Doses of Cannabinoid Type 1 Receptor Antagonist Reverses Key Alterations in Fragile X Syndrome Mouse Model.

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“Fragile X syndrome (FXS) is the most common monogenetic cause of intellectual disability.

The cognitive deficits in the mouse model for this disorder, the Fragile X Mental Retardation 1 (Fmr1) knockout (KO) mouse, have been restored by different pharmacological approaches, among those the blockade of cannabinoid type 1 (CB1) receptor.

In this regard, our previous study showed that the CB1 receptor antagonist/inverse agonist rimonabant normalized a number of core features in the Fmr1 knockout mouse. Rimonabant was commercialized at high doses for its anti-obesity properties, and withdrawn from the market on the bases of mood-related adverse effects.

In this study we show, by using electrophysiological approaches, that low dosages of rimonabant (0.1 mg/kg) manage to normalize metabotropic glutamate receptor dependent long-term depression (mGluR-LTD). In addition, low doses of rimonabant (from 0.01 mg/kg) equally normalized the cognitive deficit in the mouse model of FXS.

These doses of rimonabant were from 30 to 300 times lower than those required to reduce body weight in rodents and to presumably produce adverse effects in humans. Furthermore, NESS0327, a CB1 receptor neutral antagonist, was also effective in preventing the novel object-recognition memory deficit in Fmr1 KO mice.

These data further support targeting CB1 receptors as a relevant therapy for FXS.”

http://www.ncbi.nlm.nih.gov/pubmed/27589806

Activation of cannabinoid CB1 receptor contributes to suppression of spinal nociceptive transmission and inhibition of mechanical hypersensitivity by Aβ-fiber stimulation.

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“Activation of Aβ-fibers is an intrinsic feature of spinal cord stimulation (SCS) pain therapy.

Cannabinoid receptor type 1 (CB1) is important to neuronal plasticity and pain modulation, but its role in SCS-induced pain inhibition remains unclear.

In this study, we showed that CB1 receptors are expressed in both excitatory and inhibitory interneurons in substantia gelatinosa (SG).

Our findings suggest that activation of spinal CB1 receptors may contribute to synaptic depression to high-threshold afferent inputs in SG neurons after electrical stimulation of Aβ-fibers (Aβ-ES) and may be involved in SCS-induced inhibition of spinal nociceptive transmission after nerve injury.”

http://www.ncbi.nlm.nih.gov/pubmed/27589093