Category Archives: Pain

∆9-Tetrahydrocannabinol, a major marijuana component, enhances the anesthetic effect of pentobarbital through the CB1 receptor.

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 “∆9 –Tetrahydrocannabinol (∆9-THC) and cannabidiol (CBD), major psychoactive constituents of marijuana, induce potentiation of pentobarbital-induced sleep in mice.

We have elucidated the mechanism of enhancement of the anesthetic effect of pentobarbital by cannabinoids.

These results suggest that binding of ∆9-THC to the CB1 receptor is involved in the synergism with pentobarbital, and that potentiating effect of CBD with pentobarbital may differ from that of ∆9-THC. We successfully demonstrated that ∆9-THC enhanced the anesthetic effect of pentobarbital through the CB1 receptor.”

https://www.ncbi.nlm.nih.gov/pubmed/30636988

“The pharmacological results indicate the effect of ∆9-THC co-administered with pentobarbital was a synergistic, but not additive, action in mice. Further evidence suggests the CB1 receptor plays an important role as a trigger in potentiating pentobarbital-induced sleep by ∆9-THC.”

https://link.springer.com/article/10.1007%2Fs11419-018-0457-2

Changes in Monoaminergic Neurotransmission in an Animal Model of Osteoarthritis: The Role of Endocannabinoid Signaling.

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“Chronic pain is a main symptom of osteoarthritis (OA). Moreover, a high percentage of OA patients suffer from mental health problems.

The endocannabinoid (EC) system has attracted attention as an emerging drug target for pain treatment together with its activity on the mesolimbic reward system.

Understanding the circuits that govern the reward of pain relief is crucial for the search for effective analgesics. Therefore, we investigated the role of the EC system on dopamine (DA) and noradrenaline (NA) in an animal model of OA-related chronic pain.

Our results demonstrated that chronic pain in OA rats was reflected by the inhibition of mesolimbic and mesocortical dopaminergic transmission, and may indicate the pro-pain role of NA in the FCx.

The data provide understanding about changes in neurotransmission in chronic pain states and may explain the clinical improvement in perceived life quality following cannabinoid treatment.

Additional mechanistic studies in preclinical models examining the intersection between chronic pain and reward circuits may offer new approaches for improving pain therapy.”

https://www.ncbi.nlm.nih.gov/pubmed/30618615

https://www.frontiersin.org/articles/10.3389/fnmol.2018.00466/full

Cannabinoids-induced peripheral analgesia depends on activation of BK channels.

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 Brain Research“The endogenous cannabinoid system is involved in the physiological inhibitory control of pain and is of particular interest for the development of therapeutic approaches for pain management.

Selective activation of the peripheral CB1 cannabinoid receptor has been shown to suppress the heightened firing of primary afferents, which is the peripheral mechanism underlying neuropathic pain after nerve injury. However, the mechanism underlying this effect of CB1 receptor remains unclear.

The large-conductance calcium-activated potassium (BK) channels have been reported to participate in anticonvulsant and vasorelaxant effects of cannabinoids. We asked whether BK channels participate in cannabinoids-induced analgesia and firing-suppressing effects in primary afferents after nerve injury.

Here, using mice with chronic constriction injury(CCI)-induced neuropathic pain, antinociception action and firing-suppressing effect of HU210 were measured before and after BK channel blocker application. We found that local peripheral application of HU210 alleviated CCI-induced pain behavior and suppressed the heightened firing of injured fibers. Co-administration of IBTX with HU210 significantly reversed the analgesia and the firing-suppressing effect of HU210.

This result indicated that the peripheral analgesic effects of cannabinoids depends on activation of BK channels.”

https://www.ncbi.nlm.nih.gov/pubmed/30615887

https://www.sciencedirect.com/science/article/pii/S0006899319300071?via%3Dihub

The Anti-Inflammatory Properties of Terpenoids from Cannabis.

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“Cannabinoids are well known to have anti-inflammatory effects in mammalians; however, the Cannabis plant also contains other compounds such as terpenoids, whose biological effects have not yet been characterized. The aim of this study was to compare the anti-inflammatory properties of terpenoids with those of cannabidiol (CBD).

Materials and Methods: Essential oils prepared from three monoecious nonpsychoactive chemotypes of Cannabis were analyzed for their terpenoid content and subsequently studied pharmacologically for their anti-inflammatory properties in vitro and in vivo.

Results: In vitro, the three essential oils rich in terpenoids partly inhibited reactive oxygen intermediate and nitric oxide radical (NO•) production in RAW 264.7 stimulated macrophages. The three terpenoid-rich oils exerted moderate anti-inflammatory activities in an in vivo anti-inflammatory model without affecting tumor necrosis factor alpha (TNFα) serum levels.

Conclusions: The different Cannabis chemotypes showed distinct compositions of terpenoids. The terpenoid-rich essential oils exert anti-inflammatory and antinociceptive activities in vitro and in vivo, which vary according to their composition. Their effects seem to act independent of TNFα. None of the essential oils was as effective as purified CBD. In contrast to CBD that exerts prolonged immunosuppression and might be used in chronic inflammation, the terpenoids showed only a transient immunosuppression and might thus be used to relieve acute inflammation.”

https://www.ncbi.nlm.nih.gov/pubmed/30596146

https://www.liebertpub.com/doi/10.1089/can.2018.0014

An experimental randomized study on the analgesic effects of pharmaceutical-grade cannabis in chronic pain patients with fibromyalgia.

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“In this experimental randomized placebo-controlled 4-way crossover trial, we explored the analgesic effects of inhaled pharmaceutical-grade cannabis in twenty chronic pain patients with fibromyalgia. We tested four different cannabis varieties with exact knowledge on their [INCREMENT]-tetrahydrocannabinol (THC), and cannabidiol (CBD) content: Bedrocan® (22.4 mg THC, < 1 mg CBD), Bediol® (13.4 mg THC, 17.8 mg CBD), Bedrolite® (18.4 mg CBD, < 1 mg THC) and a placebo variety without any THC or CBD. Following a single vapor inhalation, THC and CBD plasma concentrations, pressure and electrical pain thresholds, spontaneous pain scores and drug high were measured for 3 hours. None of the treatments had an effect greater than placebo on spontaneous or electrical pain responses, although more subjects receiving Bediol® displayed a 30% decrease in pain scores compared to placebo (90% vs. 55% of patients, p = 0.01), with spontaneous pain scores correlating with the magnitude of drug high (ρ = -0.5, p < 0.001). Cannabis varieties containing THC caused a significant increase in pressure pain threshold relative to placebo (p < 0.01). CBD inhalation increased THC plasma concentrations but diminished THC-induced analgesic effects, indicative of a synergistic pharmacokinetic but antagonistic pharmacodynamic interactions of THC and CBD. This experimental trial shows the complex behavior of inhaled cannabinoids in chronic pain patients with just small analgesic responses after a single inhalation. Further studies are needed to determine long-term treatment effects on spontaneous pain scores, THC-CBD interactions and the role of psychotropic symptoms on pain relief.” https://www.ncbi.nlm.nih.gov/pubmed/30585986 https://insights.ovid.com/crossref?an=00006396-900000000-98794]]>

Medical Cannabis in the Skilled Nursing Facility: A Novel Approach to Improving Symptom Management and Quality of Life.

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Journal of the American Medical Directors Association Home “Throughout the millennia, the cannabis plant has been utilized as a recognized therapy for pain relief and symptom management. Following the Prohibition-era stigmatization and criminalization of all forms of cannabis of the early 20th century, there has been a recent nationwide and worldwide resurgence in interest and use of the cannabinoid compounds extracted from the cannabis plant, that is, medical cannabis. Although at the Federal level, cannabis remains a Schedule I substance, 31 states have already decriminalized possession and use of medical cannabis for specific diagnoses. It is noteworthy that many of these indicated diagnoses are prevalent in the skilled nursing facility (SNF). This creates regulatory concerns as SNFs and other healthcare facilities must maintain compliance with Federal laws, while balancing the individual resident’s rights to utilize medical cannabis where indicated. The authors developed an innovative program that affords their residents the ability to participate in a state-approved medical cannabis program while remaining compliant with Federal law. As medical cannabis use becomes more widespread and accepted, clinicians providing medical care in healthcare facilities will encounter residents who may benefit from and request this alternative therapy. Studies examining older adults that are utilizing medical cannabis legally have demonstrated significant decreases in prescription medication use, most notably a reduction in opioid analgesic usage. As such, medical cannabis should be viewed as an additional option in the clinician’s toolbox of therapeutic interventions for symptom relief.” https://www.ncbi.nlm.nih.gov/pubmed/30580820 https://www.jamda.com/article/S1525-8610(18)30662-5/fulltext
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