Tag Archives: cannabinoid receptors

Opioid and cannabinoid synergy in a mouse neuropathic pain model.

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“Clinical studies have reported that pan-cannabinoid receptor agonists may have efficacy in neuropathic pain states and that this might be enhanced by co-administration with opioids. While cannabinoid-opioid analgesic synergy has been demonstrated in animal models of acute pain, it has not been examined in neuropathic pain models. We examined the effect of combination treatment with cannabinoid and opioid receptor agonists on allodynia and side-effects in a nerve injury induced neuropathic pain model.

These findings indicate that combination administration of non-selective opioid and cannabinoid receptor agonists synergistically reduces nerve injury induced allodynia, while producing side-effects in an additive manner. This suggests that combination treatment has an improved anti-allodynic potency and therapeutic index in a neuropathic pain model.”

http://www.ncbi.nlm.nih.gov/pubmed/27278681

Pharmacological activation of cannabinoid 2 receptor attenuates inflammation, fibrogenesis, and promotes re-epithelialization during skin wound healing.

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“Previous studies showed that cannabinoid 2 (CB2) receptor is expressed in multiple effector cells during skin wound healing. Meanwhile, its functional involvement in inflammation, fibrosis, and cell proliferation in other organs and skin diseases implied CB2 receptor might also regulate skin wound healing.

These results, taken together, indicate that activating CB2 receptor could ameliorate wound healing by reducing inflammation, accelerating re-epithelialization, and attenuating scar formation.

Thus, CB2 receptor agonist might be a novel perspective for skin wound therapy.”

http://www.ncbi.nlm.nih.gov/pubmed/27268717

RNA-seq analysis of delta -9-tetrahydrocannabinol-treated T cells reveals altered gene expression profiles that regulate immune response and cell proliferation.

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“Marijuana has drawn significant public attention and concern both for its medicinal and recreational use. Δ9-tetrahydrocannabinol (THC), which is the main bioactive component in marijuana, has also been shown to possess potent anti-inflammatory properties by virtue of its ability to activate cannabinoid receptor-2 (CB-2) expressed on immune cells.

In this study, we used RNA-seq to quantify the transcriptomes and transcript variants that are differentially regulated by THC in super antigen-activated lymph node cells and CD4+ T cells. We found that the expressions of many transcripts were altered by THC in both total lymph node cells and CD4+ T cells. Furthermore, the abundance of many miRNA precursors and long non-coding RNAs was dramatically altered in THC treated mice. For example, the expression of miR-17/92 cluster and miR-374b/421 cluster was down regulated by THC. On the other hand miR-146a which has been shown to induce apoptosis was up regulated by THC. Long non-coding RNAs that are expressed from the opposite strand of CD27 and Appbp2 were induced by THC.

In addition, THC treatment also caused alternative promoter usage and splicing. The functions of those altered transcripts were mainly related to immune response and cell proliferation.”

http://www.ncbi.nlm.nih.gov/pubmed/27268054

Estradiol impacts the endocannabinoid system in female rats to influence behavioral and structural responses to cocaine.

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“Compared with men, women show enhanced responses to drugs of abuse, and consequently are thought to be more vulnerable to addiction.

The ovarian hormone estradiol has emerged as a key facilitator in the heightened development of addiction in females. These actions of estradiol appear mediated by estrogen receptor (ER) activation of metabotropic glutamate receptor type 5 (mGluR5). However, the downstream effectors of this ER/mGluR5 signaling pathway are unknown.

Here we investigate whether cannabinoid 1 receptor (CB1R) activation is a part of the mechanism whereby estradiol influences behavioral and synaptic correlates of addiction.

Following repeated cocaine administration, estradiol-treated ovariectomized rats exhibited both sensitized locomotor responses and decreases in the dendritic spine density of nucleus accumbens core medium-spiny neurons in comparison to oil-treated controls. Both effects of estradiol were blocked by AM251, a CB1R inverse agonist.

These results indicate that part of the signaling mechanism through which estradiol impacts behavioral and synaptic correlates of addiction in female rats requires activation of CB1Rs.”

http://www.ncbi.nlm.nih.gov/pubmed/27266915

Cannabinoid 2 (CB2) receptor agonism reduces lithium chloride-induced vomiting in Suncus murinus and nausea-induced conditioned gaping in rats.

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“We aimed to investigate the potential anti-emetic and anti-nausea properties of targeting the cannabinoid 2 (CB2) receptor.

We investigated the effect of the selective CB2 agonist, HU-308, on lithium chloride- (LiCl) induced vomiting in Suncus murinus (S. murnius) and conditioned gaping (nausea-induced behaviour) in rats.

These findings are the first to demonstrate the ability of a selective CB2 receptor agonist to reduce nausea in animal models, indicating that targeting the CB2 receptor may be an effective strategy, devoid of psychoactive effects, for managing toxin-induced nausea and vomiting.”

http://www.ncbi.nlm.nih.gov/pubmed/27263826

CB1 Receptor Antagonism Prevents Long-Term Hyperexcitability after Head Injury by Regulation of Dynorphin-KOR System and mGluR5 in Rat Hippocampus.

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“Both endocannabinoids and dynorphin are feedback messengers in nervous system that act at the presynaptic nerve terminal to inhibit transmitter release. Many studies showed the cannabinoid-opioid cross-modulation in antinociception, hypothermia, sedation and reward.

The aim of this study was to assess the influence of early application of cannabinoid type 1 (CB1) receptor antagonism SR141716A after brain injury on dynorphin-κ opioid receptor (KOR) system and the expression of metabotropic glutamate receptors (mGluRs) in a rat model of fluid percussion injury (FPI).

Firstly, seizure latency induced by pentylenetetrazole was significantly prolonged 6 weeks after brain injury in group of SR141716A treatment. Then, PCR and western blot showed that SR141716A inhibited the long-term up-regulation of CB1 receptors in hippocampus. However, SR141716A resulted in long-term potentiation of dynorphin release and did not influence the up-regulation of KOR in hippocampus after brain injury. Furthermore, SR141716A reverse the overexpression of mGluR5 in the late stage of brain injury.

We propose that during the induction of epileptogenesis after brain injury, early application of CB1 receptor antagonism could prevent long-term hyperexcitability by up-regulation of dynorphin-KOR system and prevention of mGluR5 induced epileptogenesis in hippocampus.”

http://www.ncbi.nlm.nih.gov/pubmed/27262683

Gastric acid inhibitory and gastric protective effects of Cannabis and cannabinoids.

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“Cannabis sativa has long been known for its psychotropic effect. Only recently with the discovery of the cannabinoid receptors, their endogenous legends and the enzymes responsible for their synthesis and degradation, the role of this ‘endocannabinoid system’ in different pathophysiologic processes is beginning to be delineated.

There is evidence that CB1 receptor stimulation with synthetic cannabinoids or Cannabis sativa extracts rich in Δ9-tetrahydrocannabinol inhibit gastric acid secretion in humans and experimental animals.

This is specially seen when gastric acid secretion is stimulated by pentagastrin, carbachol or 2-deoxy-d-glucose.

Cannabis and/or cannabinoids protect the gastric mucosa against noxious challenge with non-steroidal anti-inflammatory drugs, ethanol as well as against stress-induced mucosal damage.

Cannabis/cannabinoids might protect the gastric mucosa by virtue of its antisecretory, antioxidant, anti-inflammatory, and vasodilator properties.”

http://www.ncbi.nlm.nih.gov/pubmed/27261847

Cannabinoid receptor-2 stimulation suppresses neuroinflammation by regulating microglial M1/M2 polarization through the cAMP/PKA pathway in an experimental GMH rat model.

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“Excessive inflammatory responses are involved in secondary brain injury during germinal matrix hemorrhage (GMH). The process of microglial polarization to the pro-inflammatory M1 or anti-inflammatory M2 phenotypes is considered to occur in a major immunomodulatory manner during brain inflammation.

We previously found that cannabinoid receptor-2 (CB2R) stimulation attenuated microglial accumulation and brain injury following experimental GMH.

Herein, we investigated the effects of CB2R stimulation on neuroinflammation after experimental GMH and the potential mechanisms that mediate M1/M2 microglial phenotype regulation.

This is the first study to propose that promotion of microglial M2 polarization through the cAMP/PKA pathway participates in the CB2R-mediated anti-inflammatory effects after GMH induction.

The results will help to further understand the mechanisms that underlie neuroprotection by CB2R in GMH and promote clinical translational research for CB2R agonists.”

http://www.ncbi.nlm.nih.gov/pubmed/27261088

Anandamide transporter-mediated regulation of the micturition reflex in urethane-anesthetized rats.

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“The aim of this study was to investigate the effects of an anandamide transporter inhibitor that can increase endogenous anandamide concentration on the micturition reflex in urethane-anesthetized rats.

These results suggest that anandamide, an endogenous CB ligand, can modulate the micturition reflex and that anandamide transporters play an important role in this modulation. In urethane-anesthetized rats, inhibition of the uptake of anandamide can inhibit the micturition reflex and these inhibitory effects of VDM11 are at least in part mediated by the CB1 receptor.”

http://www.ncbi.nlm.nih.gov/pubmed/27256398

Clinical Effects of Synthetic Cannabinoid Receptor Agonists Compared with Marijuana in Emergency Department Patients with Acute Drug Overdose.

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“Synthetic cannabinoid receptor agonists (SCRAs) are heterogeneous compounds originally intended as probes of the endogenous cannabinoid system or as potential therapeutic agents.

In the first clinical study comparing the adverse effects of SCRA overdose vs. marijuana controls in an ED population, we found that SCRA overdoses had significantly pronounced neurotoxicity and cardiotoxicity compared with marijuana.”

http://www.ncbi.nlm.nih.gov/pubmed/27255136