Endocannabinoid modulation of inflammatory hyperalgesia in the IFN-α mouse model of depression.

Brain, Behavior, and Immunity“Depression is a well-recognised effect of long-term treatment with interferon-alpha (IFN-α), a widely used treatment for chronic viral hepatitis and malignancy. In addition to the emotional disturbances, high incidences of painful symptoms such as headache and joint pain have also been reported following IFN-α treatment.

The endocannabinoid system plays an important role in emotional and nociceptive processing, however it is unknown whether repeated IFN-α administration induces alterations in this system.

The present study investigated nociceptive responding in the IFN-α-induced mouse model of depression and associated changes in the endocannabinoid system. Furthermore, the effects of modulating peripheral endocannabinoid tone on inflammatory pain-related behaviour in the IFN-α model was examined.

In summary, increasing peripheral endocannabinoid tone attenuates inflammatory hyperalgesia induced following repeated IFN-α administration. These data provide support for the endocannabinoid system in mediating and modulating heightened pain responding associated with IFNα-induced depression.”

https://www.ncbi.nlm.nih.gov/pubmed/31505257

“Inflammatory hyperalgesia is associated with altered endocannabinoid levels. Enhancing peripheral endocannabinoid tone attenuates IFN-α related hyperalgesia.”

https://www.sciencedirect.com/science/article/pii/S0889159119306063?via%3Dihub

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The effects of cannabis, cannabinoids, and their administration routes on pain control efficacy and safety: A systematic review and network meta-analysis.

“To determine the effects of cannabis, cannabinoids, and their administration routes on pain and adverse euphoria events.

Randomized controlled trials investigating the effects of cannabis or cannabinoids on pain reduction.

RESULTS:

A total of 25 studies involving 2270 patients were included. We found that delta-9-tetrahydrocannabinol/cannabidiol (THC/CBD) (oromucosal route), THC (oromucosal route), and standardized dried cannabis (with THC; SCT; inhalation route) could reduce neuropathic pain score (SMD -0.41, 95% CI -0.7 to -0.1; -0.61, 95% CI -1.2 to -0.02; and -0.77, 95% CI -1.4 to -0.2; respectively). For nociceptive pain, only standardized cannabis extract (with THC; SCET) via oral route could reduce pain score (SMD -1.8, 95% C; -2.4 to -1.2). In cancer pain, THC/CBD via oromucosal route and THC via oral or oromucosal route could reduce pain score (SMD -0.7, 95% CI -1.2 to -0.2; and -2.1, 95% CI -2.8 to -1.4; respectively). No study was observed for THC/CBD via oral route or inhalation or THC via inhalation for cancer and nociceptive pain, SCET via oromucosal route or inhalation for neuropathic and cancer pain, THC via oromucosal route for nociceptive pain, and SCT via oromucosal or oral route for neuropathic, cancer, and nociceptive pain. Statistically significant increased risks of euphoria were observed in THC/CBD (oromucosal), THC (oromucosal), and SCT (inhalation).

CONCLUSION:

The use of cannabis and cannabinoids via certain administration routes could reduce different types of pain. Product developers could consider our findings as part of their product design so that the effective route of cannabis and cannabinoids for pain control can be achieved.”

https://www.ncbi.nlm.nih.gov/pubmed/31495691

https://www.japha.org/article/S1544-3191(19)30353-X/fulltext

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Opioid-enhancing antinociceptive effects of delta-9-tetrahydrocannabinol and amitriptyline in rhesus macaques.

Cover image for Experimental and Clinical Psychopharmacology“Cannabinoids can enhance the antinociceptive effects of opioids in a synergistic manner, potentially reducing the analgesic dosage of opioids and improving pain therapy. This strategy has also been used as a rationale to combine certain antidepressants and opioids.

In this experiment, opioid-induced thermal antinociception was assessed in rhesus macaques using a warm-water tail-withdrawal procedure with 3 water temperatures (40, 50, and 55 °C). In general, the acute antinociceptive effects of intramuscular (i.m.) cumulative doses of heroin were studied alone or in combination with i.m. (-)-trans-delta-9-tetrahydrocannabinol (THC), cannabinol (CBN), or the tricyclic antidepressant amitriptyline.

A nonantinociceptive dose of THC (1 mg/kg) shifted the ED50 for the heroin dose-effect curve 3.6-fold leftward at 50 °C and 1.9-fold leftward at 55 °C compared with heroin alone. When the cannabinoid type-1 receptor (CB1R) antagonist, rimonabant, was administered prior to the most effective THC-heroin combination, rimonabant blocked the THC enhancement of heroin antinociception. When CBN (1-3.2 mg/kg) was administered prior to heroin, or 1 mg/kg of CBN was administered prior to a combination of 0.32 mg/kg of THC and heroin, no shifts were evident in the heroin dose-effect curves at either temperature.

However, similar to THC, amitriptyline (0.32-1 mg/kg) administered prior to heroin significantly shifted the heroin dose-effect curve leftward. Heroin produced both dose- and temperature-dependent thermal antinociception in nonhuman primates and THC produced opioid-enhancing effects in a CB1R-dependent manner. These effects of THC were not shared by cannabinol, but were quantitatively similar to that of amitriptyline.”

https://www.ncbi.nlm.nih.gov/pubmed/31464475

https://psycnet.apa.org/doiLanding?doi=10.1037%2Fpha0000313

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Cannabis Use Motivations among Adults Prescribed Opioids for Pain versus Opioid Addiction.

Pain Management Nursing“Cannabis has been linked to reduced opioid use, although reasons for cannabis use among adults prescribed opioids are unclear.

The purpose of this study was to determine whether motivations for cannabis use differ between adults prescribed opioids for persistent pain versus those receiving opioids as medication-assisted treatment for opioid use disorder.

RESULTS:

More than half the sample (n = 122) reported current, daily cannabis use and 63% reported pain as a motivation for use. Adults with persistent pain were more likely to be older, female, and have higher levels of education (p < .05). Adults with opioid use disorder were more likely to report “enhancement” (p < .01) and relief of drug withdrawal symptoms (p < .001) as motivations for cannabis use. The most common reasons for cannabis use in both populations were social and recreational use and pain relief.

CONCLUSIONS:

Both studied populations have unmet health needs motivating them to use cannabis and commonly use cannabis for pain. Persistent pain participants were less likely to use cannabis for euphoric effects or withdrawal purposes. Nurses should assess for cannabis use, provide education on known risks and benefits, and offer options for holistic symptom management.”

https://www.ncbi.nlm.nih.gov/pubmed/31375419

https://www.painmanagementnursing.org/article/S1524-9042(19)30096-7/fulltext

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Cannabinoids reduce hyperalgesia and inflammation via interaction with peripheral CB1 receptors.

Image result for pain journal

“Central antinociceptive effects of cannabinoids have been well documented.

Our results indicate that cannabinoids produce antihyperalgesia via interaction with a peripheral CB1 receptor.

This hypothesis is supported by the finding that anandamide inhibited capsaicin-evoked release of calcitonin gene-related peptide from isolated hindpaw skin.

Collectively, these results indicate that cannabinoids reduce inflammation via interaction with a peripheral CB1 receptor.”

“The Endocannabinoid System and Pain. Cannabis has been used for more than twelve thousand years and for many different purposes (i.e. fiber, medicinal, recreational). However, the endocannabinoid signaling system has only recently been the focus of medical research and considered a potential therapeutic target. Cannabinoid receptors and their endogenous ligands are present at supraspinal, spinal and peripheral levels. Cannabinoids suppress behavioral responses to noxious stimulation and suppress nociceptive processing through activation of cannabinoid CB1 and CB2 receptor subtypes. These studies suggest that manipulation of peripheral endocannabinoids may be promising strategy for the management of pain.”
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2834283/

“The Analgesic Potential of Cannabinoids. Historically and anecdotally cannabinoids have been used as analgesic agents. Moreover, cannabinoids act synergistically with opioids and act as opioid sparing agents, allowing lower doses and fewer side effects from chronic opioid therapy. Thus, rational use of cannabis based medications deserves serious consideration to alleviate the suffering of patients due to severe pain.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3728280/
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Cannabinoid receptor 1 (CB1R) expression in rat dental pulp

Oral Science International“Accumulating evidence supports the role of the cannabinoid system in providing an antinociceptive effect in various painful conditions.

This effect is mediated through the Cannabinoid receptor 1 (CB1R) expressed on nociceptive afferent nerve terminals.

To investigate whether this receptor plays a similar role in dental pain, we studied the presence and distribution of CB1R in rat dental pulp.

CB1R was present on nerve fibers in rat dental pulp and possibly plays a role in dental pain mechanisms.

Interestingly, CB1R has recently been demonstrated in human dental pulp.

This strongly suggests that CB1R could be a therapeutic target for dental pain management.”

https://www.sciencedirect.com/science/article/pii/S1348864312000031

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Preparation of bivalent agonists for targeting the mu opioid and cannabinoid receptors.

European Journal of Medicinal Chemistry

“In order to obtain novel pharmacological tools and to investigate a multitargeting analgesic strategy, the CB1 and CB2 cannabinoid receptor agonist JWH-018 was conjugated with the opiate analgesic oxycodone or with an enkephalin related tetrapeptide. The opioid and cannabinoid pharmacophores were coupled via spacers of different length and chemical structure. In vitro radioligand binding experiments confirmed that the resulting bivalent compounds bound both to the opioid and to the cannabinoid receptors with moderate to high affinity. The highest affinity bivalent derivatives 11 and 19 exhibited agonist properties in [35S]GTPγS binding assays. These compounds activated MOR and CB (11 mainly CB2, whereas 19 mainly CB1) receptor-mediated signaling, as it was revealed by experiments using receptor specific antagonists. In rats both 11 and 19 exhibited antiallodynic effect similar to the parent drugs in 20 μg dose at spinal level. These results support the strategy of multitargeting G-protein coupled receptors to develop lead compounds with antinociceptive properties.”

https://www.ncbi.nlm.nih.gov/pubmed/31220675

https://www.sciencedirect.com/science/article/pii/S0223523419304477?via%3Dihub

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Δ9-tetrahydrocannabinol attenuates oxycodone self-administration under extended access conditions.

Neuropharmacology

“Growing nonmedical use of prescription opioids is a global problem, motivating research on ways to reduce use and combat addiction.

Medical cannabis (“medical marijuana”) legalization has been associated epidemiologically with reduced opioid harms and cannabinoids have been shown to modulate effects of opioids in animal models.

This study was conducted to determine if Δ9-tetrahydrocannabinol (THC) enhances the behavioral effects of oxycodone.

Together these data demonstrate additive effects of THC and oxycodone and suggest the potential use of THC to enhance therapeutic efficacy, and to reduce the abuse, of opioids.”

https://www.ncbi.nlm.nih.gov/pubmed/30980837

“Δ9-tetrahydrocannabinol (THC) enhances the antinociceptive effects of oxycodone. Vaporized and injected THC reduces oxycodone self-administration. Cannabinoids may reduce opioid use for analgesia. Cannabinoids may reduce nonmedical opioid use.”  

https://www.sciencedirect.com/science/article/pii/S0028390819301212?via%3Dihub

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Cannabidiol attenuates mechanical allodynia in streptozotocin-induced diabetic rats via serotonergic system activation through 5-HT1A receptors.

Brain Research

“Most diabetic patients describe moderate to severe pain symptoms whose pharmacological treatment is palliative and poorly effective. Cannabidiol (CBD) has shown promising results in painful conditions. Then, we aimed to investigate the potential antinociceptive effect of CBD over the mechanical allodynia in streptozotocin-induced diabetic (DBT) rats, as well as its involved mechanisms. Wistar adult male diabetic rats were treated acutely or sub-chronically (for 14 days) with CBD (0.1, 0.3 or 3 mg/Kg, intraperitoneal; i.p.) and had their mechanical threshold assessed using the electronic Von Frey. Acute treatment with CBD (at doses of 0.3 and 3 mg/Kg) exerted a significant anti-allodynic effect, which is not associated with locomotor impairment. The antinociceptive effect of CBD (3 mg/Kg) was not altered by the pre-treatment with CB1 or CB2 receptor antagonists (AM251 and AM630; respectively; both at a dose of 1 mg/kg, i.p.) nor by glycine receptor antagonist (strychnine hydrochloride, 10 μg/rat, intrathecal, i.t.). However, this effect was completely prevented by the pre-treatment with the selective 5-HT1A receptor antagonist WAY 100135 (3 μg/rat, i.t.). Sub-chronic treatment with CBD (0.3 or 3 mg/Kg) induced a sustained attenuation of the mechanical allodynia in DBT rats. DBT rats presented significantly lower spinal cord levels of serotonin, which was prevented by the daily treatment with CBD (0.3 mg/Kg). Taken together, our data suggest that CBD may be effective in the treatment of painful diabetic neuropathy and this effect seems to be potentially mediated by the serotonergic system activation through 5-HT1A receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/30898678

https://www.sciencedirect.com/science/article/pii/S0006899319301532?via%3Dihub

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Characterization of Cancer-Induced Nociception in a Murine Model of Breast Carcinoma.

“Severe and poorly treated pain often accompanies breast cancer. Thus, novel mechanisms involved in breast cancer-induced pain should be investigated. Then, it is necessary to characterize animal models that are reliable with the symptoms and progression of the disease as observed in humans. Explaining cancer-induced nociception in a murine model of breast carcinoma was the aim of this study. 4T1 (104) lineage cells were inoculated in the right fourth mammary fat pad of female BALB/c mice; after this, mechanical and cold allodynia, or mouse grimace scale (MGS) were observed for 30 days. To determine the presence of bone metastasis, we performed the metastatic clonogenic test and measure calcium serum levels. At 20 days after tumor induction, the antinociceptive effect of analgesics used to relieve pain in cancer patients (acetaminophen, naproxen, codeine or morphine) or a cannabinoid agonist (WIN 55,212-2) was tested. Mice inoculated with 4T1 cells developed mechanical and cold allodynia and increased MGS. Bone metastasis was confirmed using the clonogenic assay, and hypercalcemia was observed 20 days after cells inoculation. All analgesic drugs reduced the mechanical and cold allodynia, while the MGS was decreased only by the administration of naproxen, codeine, or morphine. Also, WIN 55,212-2 improved all nociceptive measures. This pain model could be a reliable form to observe the mechanisms of breast cancer-induced pain or to observe the efficacy of novel analgesic compounds.”

https://www.ncbi.nlm.nih.gov/pubmed/30850915

https://link.springer.com/article/10.1007%2Fs10571-019-00666-8

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