Tag Archives: cannabinoid receptors

Current evidence of cannabinoid-based analgesia obtained in preclinical and human experimental settings.

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European Journal of Pain

“Cannabinoids have a long record of recreational and medical use and become increasingly approved for pain therapy. This development is based on preclinical and human experimental research summarized in this review.

Cannabinoid CB1 receptors are widely expressed throughout the nociceptive system. Their activation by endogenous or exogenous cannabinoids modulates the release of neurotransmitters. This is reflected in antinociceptive effects of cannabinoids in preclinical models of inflammatory, cancer and neuropathic pain, and by nociceptive hypersensitivity of cannabinoid receptor-deficient mice.

Cannabis-based medications available for humans mainly comprise Δ9 -tetrahydrocannabinol (THC), cannabidiol (CBD) and nabilone.

During the last 10 years, six controlled studies assessing analgesic effects of cannabinoid-based drugs in human experimental settings were reported. An effect on nociceptive processing could be translated to the human setting in functional magnetic resonance imaging studies that pointed at a reduced connectivity within the pain matrix of the brain. However, cannabinoid-based drugs heterogeneously influenced the perception of experimentally induced pain including a reduction in only the affective but not the sensory perception of pain, only moderate analgesic effects, or occasional hyperalgesic effects. This extends to the clinical setting.

While controlled studies showed a lack of robust analgesic effects, cannabis was nearly always associated with analgesia in open-label or retrospective reports, possibly indicating an effect on well-being or mood, rather than on sensory pain. Thus, while preclinical evidence supports cannabinoid-based analgesics, human evidence presently provides only reluctant support for a broad clinical use of cannabinoid-based medications in pain therapy.

SIGNIFICANCE:

Cannabinoids consistently produced antinociceptive effects in preclinical models, whereas they heterogeneously influenced the perception of experimentally induced pain in humans and did not provide robust clinical analgesia, which jeopardizes the translation of preclinical research on cannabinoid-mediated antinociception into the human setting.”

https://www.ncbi.nlm.nih.gov/pubmed/29160600

http://onlinelibrary.wiley.com/doi/10.1002/ejp.1148/abstract?systemMessage=Wiley+Online+Library+usage+report+download+page+will+be+unavailable+on+Friday+24th+November+2017+at+21%3A00+EST+%2F+02.00+GMT+%2F+10%3A00+SGT+%28Saturday+25th+Nov+for+SGT+

Effects of chronic Δ9-tetrahydrocannabinol treatment on Rho/Rho-kinase signalization pathway in mouse brain.

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Saudi Pharmaceutical Journal

“Δ9-Tetrahydrocannabinol (Δ9-THC) shows its effects by activating cannabinoid receptors which are on some tissues and neurons. Cannabinoid systems have role on cell proliferation and development of neurons. Furthermore, it is interesting that cannabinoidsystem and rho/rho-kinase signalization pathway, which have important role on cell development and proliferation, may have role on neuron proliferation and development together. Thus, a study is planned to investigate rhoA and rho-kinase enzyme expressions and their activities in the brain of chronic Δ9-THC treated mice. One group of mice are treated with Δ9-THC once to see effects of acute treatment. Another group of mice are treated with Δ9-THC three times per day for one month. After this period, rhoA and rho-kinase enzyme expressions and their activities in mice brains are analyzed by ELISA method. Chronic administration of Δ9-THC decreased the expression of rhoA while acute treatment has no meaningful effect on it. Administration of Δ9-THC did not affect expression of rho-kinase on both chronic and acute treatment. Administration of Δ9-THC increased rho-kinase activity on both chronic and acute treatment, however, chronic treatment decreased its activity with respect to acute treatment. This study showed that chronic Δ9-THC treatment down-regulated rhoA expression and did not change the expression level of rho-kinase which is downstream effector of rhoA. However, it elevated the rho-kinase activity. Δ9-THC induced down-regulation of rhoA may cause elevation of cypin expression and may have benefit on cypin related diseases. Furthermore, use of rho-kinase inhibitors and Δ9-THC together can be useful on rho-kinase related diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/29158718
http://www.sciencedirect.com/science/article/pii/S1319016417301081?via%3Dihub

Modulating the endocannabinoid pathway as treatment for peripheral neuropathic pain: a selected review of preclinical studies.

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“Chemotherapy-induced neuropathic pain is a distressing and commonly occurring side effect of many commonly used chemotherapeutic agents, which in some cases may prevent cancer patients from being able to complete their treatment.

Cannabinoid based therapies have the potential to manage or even prevent pain associated with this syndrome.

Pre-clinical animal studies that investigate the modulation of the endocannabinoid system (endogenous cannabinoid pathway) are being conducted to better understand the mechanisms behind this phenomenon.

Five recent pre-clinical studies identified from Medline published between 2013 and 2016 were selected for review. All studies evaluated the effect of small-molecule agonists or antagonists on components of the endocannabinoid system in rats or mice, using cisplatin or paclitax-el-induced allodynia as a model of chemotherapy-induced neuropathic pain. Activation of the cannabinoid receptor-2 (CB-2) receptor by AM1710 blocked paclitaxel-induced mechanical and cold allodynia in one study.

Four studies investigating the activation of both cannabinoid receptor-1 (CB-1) and CB-2 receptors by dual-agonists (WIN55,21 and CP55,940), or by the introduction of inhibitors of endocannabinoid metabolisers (URB597, URB937, JZL184, and SA-57) showed reduction of chemotherapy-induced al-lodynia. In addition, their results suggest that anti-allodynic effects may also be mediated by additional receptors, including TRPV1 and 5-hydroxytryptamine (5-HT1A).

Pre-clinical studies demon-strate that the activation of endocannabinoid CB-1 or CB-2 receptors produces physiological effects in animal models, namely the reduction of chemotherapy-induced allodynia. These studies also provide in-sight into the biological mechanism behind the therapeutic utility of cannabis compounds in managing chemotherapy-induced neuropathic pain, and provide a basis for the conduct of future clinical studies in patients of this population.”

https://www.ncbi.nlm.nih.gov/pubmed/29156899
http://apm.amegroups.com/article/view/16320

Medical cannabis Q&A

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Logo of canpharmj

  • “1. What is medical cannabis?

The term “medical cannabis” is used to describe products derived from the whole cannabis plant or its extracts containing a variety of active cannabinoids and terpenes, which patients take for medical reasons, after interacting with and obtaining authorization from their health care practitioner.

  • 2. What are the main active ingredients?

The chemical ingredients of cannabis are called cannabinoids. The 2 main therapeutic ones are:

  •  A Tetrahydrocannabinol (THC) is a partial agonist of CB1 and CB2 receptors. It is psychoactive and produces the euphoric effect.
  •  B Cannabidiol (CBD) has a weak affinity for CB1 and CB2 receptors and appears to exert its activity by enhancing the positive effects of the body’s endogenous cannabinoids
 3. Why do patients take it?

Medical cannabis may be used to alleviate symptoms for a variety of conditions. It has most commonly been used in neuropathic pain and other chronic pain conditions. There is limited, but developing, clinical evidence surrounding its safety and efficacy, and it does not currently have an approved Health Canada indication.

  • 4. How do patients take it?

Cannabis can be smoked, vaporized, taken orally, sublingually, topically or rectally. Different routes of administration will result in different pharmacokinetic and pharmacodynamic properties of the drug.

  • 5. Is it possible to develop dependence on medical cannabis?

Yes, abrupt discontinuation after long-term use may result in withdrawal symptoms. Additionally, chronic use may result in psychological dependence.

  • 6. What is the difference between medical and recreational cannabis?

Patients taking cannabis for medical reasons generally use cannabinoids to alleviate symptoms while minimizing intoxication, whereas recreational users may be taking cannabis for euphoric effects. Medical cannabis is authorized by a prescriber who provides a medical document allowing individuals to obtain cannabis from a licensed producer or apply to Health Canada to grow their own, whereas recreational cannabis is currently obtained through illicit means.

  • 7. How can patients access cannabis for medical purposes?
  • 8. Does medical cannabis have a DIN?

Pharmacological cannabinoids such as Sativex (delta-9-tetrahydrocannabinol-cannabidiol) and Cesamet (nabilone) have been approved for specific indications by Health Canada, however, herbal medical cannabis has not gone through Health Canada’s drug review and approval process, nor does it have a Drug Identification Number (DIN) or Natural Product Number (NPN).

  • 9. Is medical cannabis covered through insurance?

Some insurance plans may cover medical cannabis. Check each patient’s individual plan for more details.

  • 10. What role can pharmacists play in medical cannabis?

Even though pharmacists are not dispensing medical cannabis at this time, it is important for them to understand how their patients may use and access medical cannabis in order to provide effective medication management. Pharmacists may provide counselling on areas such as contraindications, drug interactions, management of side effects, alternative therapies, potential addictive behaviour and appropriate use.

  • 11. Where can I find more information about medical cannabis?

You can find more information on Health Canada’s website:” https://www.canada.ca/en/health-canada/services/drugs-health-products/medical-use-marijuana/medical-use-marijuana.html

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5661684/

Cannabinoid Receptor Type 1 Agonist ACEA Protects Neurons from Death and Attenuates Endoplasmic Reticulum Stress-Related Apoptotic Pathway Signaling.

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Neurotoxicity Research

“Neurodegeneration is the result of progressive destruction of neurons in the central nervous system, with unknown causes and pathological mechanisms not yet fully elucidated. Several factors contribute to neurodegenerative processes, including neuroinflammation, accumulation of neurotoxic factors, and misfolded proteins in the lumen of the endoplasmic reticulum (ER).

Endocannabinoid signaling has been pointed out as an important modulatory system in several neurodegeneration-related processes, inhibiting the inflammatory response and increasing neuronal survival. Thus, we investigated the presumptive protective effect of the selective cannabinoid type 1 (CB1) receptor agonist) against inflammatory (lipopolysaccharide, LPS) and ER stress (tunicamycin) stimuli in an in vitro neuronal model (Neuro-2a neuroblastoma cells). Cell viability analysis revealed that ACEA was able to protect against cell death induced by LPS and tunicamycin.

This neuroprotective effect occurs via the CB1 receptor in the inflammation process and via the transient receptor potential of vanilloid type-1 (TRPV1) channel in ER stress. Furthermore, the immunoblotting analyses indicated that the neuroprotective effect of ACEA seems to involve the modulation of eukaryotic initiation factor 2 (eIF2α), transcription factor C/EBP homologous protein (CHOP), and caspase 12, as well as the survival/death p44/42 MAPK, ERK1/2-related signaling pathways.

Together, these data suggest that the endocannabinoid system is a potential therapeutic target in neurodegenerative processes, especially in ER-related neurodegenerative diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/29134561

https://link.springer.com/article/10.1007%2Fs12640-017-9839-1

Involvement of cannabinoid receptor type 2 in light-induced degeneration of cells from mouse retinal cell line in vitro and mouse photoreceptors in vivo.

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Experimental Eye Research

“Earlier studies showed that the expressions of the agonists of the cannabinoid receptors are reduced in the vitreous humor of patients with age-related macular degeneration (AMD), and the cannabinoid type 2 receptor is present in the retinas of rats and monkeys. The purpose of this study was to determine whether the cannabinoid type 2 receptor is involved in the light-induced death of cultured 661W cells, an immortalized murine retinal cell line, and in the light-induced retinal degeneration in mice.

Time-dependent changes in the expression and location of retinal cannabinoid type 2 receptor were determined by Western blot and immunostaining. The cannabinoid type 2 receptor was down-regulated in murine retinae and cone cells. In the in vitro studies, HU-308, a cannabinoidtype 2 receptor agonist, had a protective effect on the light-induced death of 661W cells, and this effect was attenuated by SR144528, a cannabinoid type 2 receptor antagonist.

Because the cannabinoid type 2 receptor is a G-protein coupled receptor and is coupled with Gi/o protein, we investigated the effects of the cAMP-dependent protein kinase (PKA). HU-308 and H89, a PKA inhibitor, deactivated PKA in retinal cone cells, and H89 also suppressed light-induced cell death. For the in vivo studies, a cannabinoid type 2 receptor agonist, HU-308, or an antagonist, SR144528, was injected intravitreally into mouse eyes before the light exposure. Electroretinography was used to determine the physiological status of the retinas. Injection of HU-308 improved the a- and b-waves of the ERGs and also the thickness of the outer nuclear layer of the murine retina after light exposure.

These findings indicate that the cannabinoid type 2 receptor is involved in the light-induced retinal damage through PKA signaling. Thus, activation of cannabinoidtype 2 receptor may be a therapeutic approach for light-associated retinal diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/29133122

http://www.sciencedirect.com/science/article/pii/S0014483516304456?via%3Dihub

Hypoxia-induced inhibition of the endocannabinoid system in glioblastoma cells.

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Journal Cover

“The endocannabinoid system plays an important role in the regulation of physiological and pathological conditions, including inflammation and cancer.

Hypoxia is a fundamental phenomenon for the establishment and maintenance of the microenvironments in various physiological and pathological conditions. However, the influence of hypoxia on the endocannabinoid system is not fully understood. In the present study, we investigated the effects of hypoxia on the endocannabinoid system in malignant brain tumors.

Although cannabinoid receptor (CB) engagement induces cell death in U-87 MG cells in normoxic conditions, CB agonist-induced death was attenuated in hypoxic conditions. These results suggest that hypoxia modifies the endocannabinoid system in glioblastoma cells.

Hypoxia-induced inhibition of the endocannabinoid system may aid the development of glioblastoma.”

https://www.ncbi.nlm.nih.gov/pubmed/29130103

https://www.spandidos-publications.com/10.3892/or.2017.6048

ACPA and JWH-133 modulate the vascular tone of superior mesenteric arteries through cannabinoid receptors, BKCa channels, and nitric oxide dependent mechanisms.

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Pharmacological Reports

“Some cannabinoids, a family of compounds derived from Cannabis sativa (marijuana), have previously shown vasodilator effects in several studies, a feature that makes them suitable for the generation of a potential treatment for hypertension.

The mechanism underlying this vasodilator effect in arteries is still controversial. In this report, we explored how the synthetic cannabinoids ACPA (CB1-selective agonist) and JWH-133 (CB2-selective agonist) regulate the vascular tone of rat superior mesenteric arteries.

CB1 and CB2 receptor activation in superior mesenteric artery causes vasorelaxation by mechanisms involving BKCachannels and NO release.”

https://www.ncbi.nlm.nih.gov/pubmed/29128791

http://www.sciencedirect.com/science/article/pii/S1734114017300361?via%3Dihub

Anti-migraine effect of ∆9-tetrahydrocannabinol in the female rat.

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European Journal of Pharmacology

“Current anti-migraine treatments have limited efficacy and many side effects. Although anecdotal evidence suggests that marijuana is useful for migraine, this hypothesis has not been tested in a controlled experiment. Thus, the present study tested whether administration of ∆9-tetrahydrocannabinol (THC) produces anti-migraine effects in the female rat.

These data suggest that: 1) THC reduces migraine-like pain when administered at the right dose (0.32mg/kg) and time (immediately after AITC); 2) THC’s anti-migraine effect is mediated by CB1 receptors; and 3) Wheel running is an effective method to assess migraine treatments because only treatments producing antinociception without disruptive side effects will restore normal activity.

These findings support anecdotal evidence for the use of cannabinoids as a treatment for migraine in humans and implicate the CB1 receptor as a therapeutic target for migraine.”

https://www.ncbi.nlm.nih.gov/pubmed/29111112

http://www.sciencedirect.com/science/article/pii/S0014299917307239?via%3Dihub

Masturbation to Orgasm Stimulates the Release of the Endocannabinoid 2-Arachidonoylglycerol in Humans.

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The Journal of Sexual Medicine - Click here to go back to the homepage

“Endocannabinoids are critical for rewarding behaviors such as eating, physical exercise, and social interaction. The role of endocannabinoids in mammalian sexual behavior has been suggested because of the influence of cannabinoid receptor agonists and antagonists on rodent sexual activity. However, the involvement of endocannabinoids in human sexual behavior has not been studied.

AIM:

To investigate plasma endocannabinoid levels before and after masturbation in healthy male and female volunteers.

OUTCOMES:

Plasma levels of the endocannabinoids 2-arachidonoylglycerol (2-AG), anandamide, the endocannabinoid-like lipids oleoyl ethanolamide and palmitoyl ethanolamide, arachidonic acid, and cortisol before and after masturbation to orgasm.

METHODS:

In study 1, endocannabinoid and cortisol levels were measured before and after masturbation to orgasm. In study 2, masturbation to orgasm was compared with a control condition using a single-blinded, randomized, 2-session crossover design.

RESULTS:

In study 1, masturbation to orgasm significantly increased plasma levels of the endocannabinoid 2-AG, whereas anandamide, oleoyl ethanolamide, palmitoyl ethanolamide, arachidonic acid, and cortisol levels were not altered. In study 2, only masturbation to orgasm, not the control condition, led to a significant increase in 2-AG levels. Interestingly, we also found a significant increase of oleoyl ethanolamide after masturbation to orgasm in study 2.

CLINICAL TRANSLATION:

Endocannabinoids might play an important role in the sexual response cycle, leading to possible implications for the understanding and treatment of sexual dysfunctions.

STRENGTHS AND LIMITATIONS:

We found an increase of 2-AG through masturbation to orgasm in 2 studies including a single-blinded randomized design. The exact role of endocannabinoid release as part of the sexual response cycle and the biological significance of the finding should be studied further. Cannabis and other drug use and the attainment of orgasm were self-reported in the present study.

CONCLUSION:

Our data indicate that the endocannabinoid 2-AG is involved in the human sexual response cycle and we hypothesize that 2-AG release plays a role in the rewarding consequences of sexual arousal and orgasm.”

https://www.ncbi.nlm.nih.gov/pubmed/29110806

http://www.jsm.jsexmed.org/article/S1743-6095(17)31443-1/fulltext