Category Archives: Pain

Cannabis for Pain and Headaches: Primer.

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“Marijuana has been used both medicinally and recreationally since ancient times and interest in its compounds for pain relief has increased in recent years. The identification of our own intrinsic, endocannabinoid system has laid the foundation for further research.

Synthetic cannabinoids are being developed and synthesized from the marijuana plant such as dronabinol and nabilone. The US Food and Drug Administration approved the use of dronabinol and nabilone for chemotherapy-associated nausea and vomiting and HIV (Human Immunodeficiency Virus) wasting. Nabiximols is a cannabis extract that is approved for the treatment of spasticity and intractable pain in Canada and the UK. Further clinical trials are studying the effect of marijuana extracts for seizure disorders.

Phytocannabinoids have been identified as key compounds involved in analgesia and anti-inflammatory effects.  Other compounds found in cannabis such as flavonoids and terpenes are also being investigated as to their individual or synergistic effects.

This article will review relevant literature regarding medical use of marijuana and cannabinoid pharmaceuticals with an emphasis on pain and headaches.”

https://www.ncbi.nlm.nih.gov/pubmed/28281107

Cannabinoid signaling in health and disease.

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“Cannabis sativa has long been used for medicinal purposes.

To improve safety and efficacy, compounds from C. sativa were purified or synthesized and named under an umbrella group as cannabinoids.

Currently, several cannabinoids may be prescribed in Canada for a variety of indications such as nausea and pain.

More recently, an increasing number of reports suggest other salutary effects associated with endogenous cannabinoid signaling including cardioprotection.

The therapeutic potential of cannabinoids is therefore extended; however, evidence is limited and mechanisms remain unclear.

In addition, the use of cannabinoids clinically has been hindered due to pronounced psychoactive side effects.

This review provides an overview on the endocannabinoid system, including known physiological roles, and conditions in which cannabinoid receptor signaling has been implicated.”

 https://www.ncbi.nlm.nih.gov/pubmed/28263083

Allodynia Lowering Induced by Cannabinoids and Endocannabinoids (ALICE).

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“Neuropathic pain is a neurological disorder that strongly affects the quality of life of patients. The molecular and cellular mechanisms at the basis of the neuropathic pain establishment still need to be clarified. Among the neuromodulators involved in the pathological pain pathways, endocannabinoid system could be deeply involved in both neuronal and non-neuronal mechanisms responsible for the appearance of tactile allodynia. Indeed, the function and dysfunction of this complex system in the molecular and cellular mechanisms of chronic pain induction and maintenance has been widely studied over the last two decades. In this review article, we highlighted the possible modulation of the endocannabinoid system in the neuronal, glial and microglial modulation in neuropathic pain treatment.”

https://www.ncbi.nlm.nih.gov/pubmed/28237514

Cannabinoid receptor 2 agonist attenuates pain related behavior in rats with chronic alcohol/high fat diet induced pancreatitis

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“Chronic Pancreatitis (CP) is a complex and multifactorial syndrome. Many contributing factors result in development of dysfunctional pain in a significant number of patients. Drugs developed to treat a variety of pain states fall short of providing effective analgesia for patients with chronic pancreatitis, often providing minimal to partial pain relief over time with significant side effects.

Recently, availability of selective pharmacological tools has enabled great advances in our knowledge of the role of the cannabinoid receptors in pathophysiology. In particular, cannabinoid receptor 2 (CB2) has emerged as an attractive target for management of chronic pain, as demonstrated in several studies with inflammatory and neuropathic preclinical pain models. In this study, the analgesic efficacy of a novel, highly selective CB2 receptor agonist, LY3038404 HCl, is investigated in a chronic pancreatitis pain model, induced with an alcohol/high fat (AHF) diet.

LY3038404 HCl, a potent CB2 receptor agonist, possesses tissue protective and analgesic properties without effects on higher brain function. Thus, activation of CB2 receptors is suggested as a potential therapeutic target for visceral inflammation and pain management.

The major finding of the present study is that LY3038404 HCl, a potent CB2 receptor agonist, possesses tissue protective and analgesic properties. No effects on higher brain functions were observed including the diminished fear responses induced by the alcohol diet. Thus, activation of CB2 receptors is suggested as a potential therapeutic target for pancreas protection and pain management.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4242547/

Gut-brain axis: Role of lipids in the regulation of inflammation, pain and CNS diseases.

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“The human gut is a composite anaerobic environment with a large, diverse and dynamic enteric microbiota, represented by more than 100 trillion microorganisms, including at least 1000 distinct species. The discovery that a different microbial composition can influence behavior and cognition, and in turn the nervous system can indirectly influence enteric microbiota composition, has significantly contributed to establish the well-accepted concept of gut-brain axis.

This hypothesis is supported by several evidence showing mutual mechanisms, which involve the vague nerve, the immune system, the hypothalamic-pituitary-adrenal (HPA) axis modulation and the bacteria-derived metabolites. Many studies have focused on delineating a role for this axis in health and disease, ranging from stress-related disorders such as depression, anxiety and irritable bowel syndrome (IBS) to neurodevelopmental disorders, such as autism, and to neurodegenerative diseases, such as Parkinson Disease, Alzheimer Disease etc.

Based on this background, and considering the relevance of alteration of the symbiotic state between host and microbiota, this review focuses on the role and the involvement of bioactive lipids, such as the N-acylethanolamine (NAE) family whose main members are N-arachidonoylethanolamine (AEA), palmitoylethanolamide (PEA) and oleoilethanolamide (OEA), and short chain fatty acids (SCFAs), such as butyrate, belonging to a large group of bioactive lipids able to modulate peripheral and central pathologic processes.

It is well established their effective role in inflammation, acute and chronic pain, obesity and central nervous system diseases. It has been shown a possible correlation between these lipids and gut microbiota through different mechanisms.

Indeed, systemic administration of specific bacteria can reduce abdominal pain through the involvement of cannabinoid receptor 1 in rat; on the other hand, PEA reduces inflammation markers in a murine model of inflammatory bowel disease (IBD), and butyrate, producted by gut microbiota, is effective in reducing inflammation and pain in irritable bowel syndrome and IBD animal models.

In this review, we underline the relationship among inflammation, pain, microbiota and the different lipids, focusing on a possible involvement of NAEs and SCFAs in the gut-brain axis and their role in central nervous system diseases.”

https://www.ncbi.nlm.nih.gov/pubmed/28215162

Modulation of Human Peripheral Blood Mononuclear Cell Signaling by Medicinal Cannabinoids.

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“Medical marijuana is increasingly prescribed as an analgesic for a growing number of indications, amongst which terminal cancer and multiple sclerosis.

In this study we aimed to investigate the immune-cell modulatory properties of medical cannabis.

Healthy volunteers were asked to ingest medical cannabis, and kinome profiling was used to generate comprehensive descriptions of the cannabis challenge on inflammatory signal transduction in the peripheral blood of these volunteers.

Results were related to both short term and long term effects in patients experimentally treated with a medical marijuana preparation for suffering from abdominal pain as a result of chronic pancreatitis or other causes.

The results reveal an immunosuppressive effect of cannabinoid preparations via deactivation of signaling through the pro-inflammatory p38 MAP kinase and mTOR pathways and a concomitant deactivation of the pro-mitogenic ERK pathway. However, long term cannabis exposure in two patients resulted in reversal of this effect.

While these data provide a powerful mechanistic rationale for the clinical use of medical marijuana in inflammatory and oncological disease, caution may be advised with sustained use of such preparations.”

https://www.ncbi.nlm.nih.gov/pubmed/28174520

http://journal.frontiersin.org/article/10.3389/fnmol.2017.00014/full

Use of medical cannabis to reduce pain and improve quality of life in cancer patients.

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“Early attention to pain and symptoms in those with cancer improves both quality of life and survival. Opioid medications are the mainstay treatment of cancer-related pain.

Cannabinoids are increasingly used as adjunctive treatments for cancer pain, but clinical evidence supporting their use as an “opioid sparing agent” or to improve quality of life is as yet unknown. Our study sought to determine if the addition of cannabinoids (medical cannabis) resulted in the reduction of the average opioid dose required for pain control, and improve self-reported quality of life indices.

CONCLUSIONS:

Patients with cancer pain benefited from the addition of cannabinoids. The average opioid dose decreased following access to medical cannabis. Self-reported ratings of several quality of life indicators showed statistically significant improvement. Our study shows a signal that cannabinoids may reduce cancer patients’ reliance on opioids to control pain. Further prospective controlled studies are needed to further elucidate the role of cannabinoids in the treatment of cancer pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28148191

Antihyperalgesic effect of CB1 receptor activation involves the modulation of P2X3 receptor in the primary afferent neuron.

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“Cannabinoid system is a potential target for pain control.

Cannabinoid receptor 1 (CB1) activation play a role in the analgesic effect of cannabinoids once it is expressed in primary afferent neurons.

This study investigates whether the anti-hyperalgesic effect of CB1receptor activation involves P2×3 receptor in primary afferent neurons.

Our data suggest that the analgesic effect of CB1 receptor activation is mediated by a negative modulation of the P2×3 receptor in the primary afferent neurons.”

https://www.ncbi.nlm.nih.gov/pubmed/28131783

Compensatory Activation of Cannabinoid CB2 Receptor Inhibition of GABA Release in the Rostral Ventromedial Medulla in Inflammatory Pain.

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“The rostral ventromedial medulla (RVM) is a relay in the descending pain modulatory system and an important site of endocannabinoid modulation of pain.

Our data provide evidence that CB2 receptor function emerges in the RVM in persistent inflammation and that selective CB2 receptor agonists may be useful for treatment of persistent inflammatory pain.

SIGNIFICANCE STATEMENT:

These studies demonstrate that endocannabinoid signaling to CB1 and CB2 receptors in adult rostral ventromedial medulla is altered in persistent inflammation. The emergence of CB2 receptor function in the rostral ventromedial medulla provides additional rationale for the development of CB2 receptor-selective agonists as useful therapeutics for chronic inflammatory pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28100744

Synergistic attenuation of chronic pain using mu opioid and cannabinoid receptor 2 agonists.

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“The misuse of prescription opiates is on the rise with combination therapies (e.g. acetaminophen or NSAIDs) resulting in severe liver and kidney damage. In recent years, cannabinoid receptors have been identified as potential modulators of pain and rewarding behaviors associated with cocaine, nicotine and ethanol in preclinical models. Yet, few studies have identified whether mu opioid agonists and CB2 agonists act synergistically to inhibit chronic pain while reducing unwanted side effects including reward liability.

We determined if analgesic synergy exists between the mu-opioid agonist morphine and the selective CB2 agonist, JWH015, in rodent models of acute and chronic inflammatory, post-operative, and neuropathic pain using isobolographic analysis. We also investigated if the MOR-CB2 agonist combination decreased morphine-induced conditioned place preference (CPP) and slowing of gastrointestinal transit. Co-administration of morphine with JWH015 synergistically inhibited preclinical inflammatory, post-operative and neuropathic-pain in a dose- and time-dependent manner; no synergy was observed for nociceptive pain. Opioid-induced side effects of impaired gastrointestinal transit and CPP were significantly reduced in the presence of JWH015.

Here we show that MOR + CB2 agonism results in a significant synergistic inhibition of preclinical pain while significantly reducing opioid-induced unwanted side effects.

The opioid sparing effect of CB2 receptor agonism strongly supports the advancement of a MOR-CB2 agonist combinatorial pain therapy for clinical trials.”

https://www.ncbi.nlm.nih.gov/pubmed/28007501