Category Archives: Pain

Single oral dose of cannabinoid derivate loaded PLGA nanocarriers relieves neuropathic pain for eleven days.

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Nanomedicine Home

“Neuropathic pain, resistant to opiates and other drugs, is a chronic/persistent state with a complex treatment and often poor efficacy. In this scenario, cannabinoids are increasingly regarded as a genuine alternative. In this paper, and in an experimental animal model of neuropathic pain, we studied the efficacy of three kinds of PLGA nanoparticles containing synthetic cannabinoid CB13: (i) plain nanoparticles (PLGA); (ii) particles coated with PEG chains (PLGA+PEG) and (iii) particles possessing hydrophilic surfaces obtained by covalently binding PEG chains (PLGA-PEG). The optimized formulation, CB13-PLGA-PEG, showed high drug loading (13%) and small size (<300nm) with a narrow distribution and controlled surface properties (near-neutral zeta potential and stable PEG corona). Animal nociceptive behavioral studies were conducted by paw pressure and acetone tests. Versus the free CB13, CB13-PLGA-PEG nanoparticles showed a very noticeable analgesic efficacy with the longest sustained pain-relieving effect, lasting up to eleven days after one oral dose.”

https://www.ncbi.nlm.nih.gov/pubmed/28756090

http://www.nanomedjournal.com/article/S1549-9634(17)30140-5/fulltext

Endocannabinoid Transport Proteins: Discovery of Tools to Study Sterol Carrier Protein-2.

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Elsevier

“The endocannabinoid (eCB) neurotransmitter system regulates diverse neurological functions including stress and anxiety, pain, mood, and reward. Understanding the mechanisms underlying eCB regulation is critical for developing targeted pharmacotherapies to treat these and other neurologic disorders.

Cellular studies suggest that the arachidonate eCBs, N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG), are substrates for intracellular binding and transport proteins, and several candidate proteins have been identified. Initial evidence from our laboratory indicates that the lipid transport protein, sterol carrier protein 2 (SCP-2), binds to the eCBs and can regulate their cellular concentrations.

Here, we present methods for evaluating SCP-2 binding of eCBs and their application to the discovery of the first inhibitor lead molecules. Using a fluorescent probe displacement assay, we found SCP-2 binds the eCBs, AEA (Ki=0.68±0.05μM) and 2-AG (Ki=0.37±0.02μM), with moderate affinity. A series of structurally diverse arachidonate analogues also bind SCP-2 with Ki values between 0.82 and 2.95μM, suggesting a high degree of tolerance for arachidonic acid head group modifications in this region of the protein. We also report initial structure-activity relationships surrounding previously reported inhibitors of Aedis aegypti SCP-2, and the results of an in silico high-throughput screen that identified structurally novel SCP-2 inhibitor leads.

The methods and results reported here provide the basis for a robust probe discovery effort to fully elucidate the role of facilitated transport mediated by SCP-2 in eCB regulation and function.”

https://www.ncbi.nlm.nih.gov/pubmed/28750817

http://www.sciencedirect.com/science/article/pii/S007668791730174X?via%3Dihub

 

Endocannabinoids Have Opposing Effects On Behavioral Responses To Nociceptive And Non-nociceptive Stimuli.

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“The endocannabinoid system is thought to modulate nociceptive signaling making it a potential therapeutic target for treating pain.

However, there is evidence that endocannabinoids have both pro- and anti-nociceptive effects. In previous studies using Hirudo verbana (the medicinal leech), endocannabinoids were found to depress nociceptive synapses, but enhance non-nociceptive synapses. Here we examined whether endocannabinoids have similar bidirectional effects on behavioral responses to nociceptive vs. non-nociceptive stimuli in vivo.

These results provide evidence that endocannabinoids can have opposing effects on nociceptive vs. non-nociceptive pathways and suggest that cannabinoid-based therapies may be more appropriate for treating pain disorders in which hyperalgesia and not allodynia is the primary symptom.”

 https://www.ncbi.nlm.nih.gov/pubmed/28724917
https://www.nature.com/articles/s41598-017-06114-1

Delta-9-tetrahydrocannabinol decreases masticatory muscle sensitization in female rats through peripheral cannabinoid receptor activation.

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European Journal of Pain

“This study investigated whether intramuscular injection of delta-9-tetrahydrocannabinol (THC), by acting on peripheral cannabinoid (CB) receptors, could decrease nerve growth factor (NGF)-induced sensitization in female rat masseter muscle; a model which mimics the symptoms of myofascial temporomandibular disorders.

It was found that CB1 and CB2 receptors are expressed by trigeminal ganglion neurons that innervate the masseter muscle and also on their peripheral endings.

These results suggest that reduced inhibitory input from the peripheral cannabinoid system may contribute to NGF-induced local myofascial sensitization of mechanoreceptors. Peripheral application of THC may counter this effect by activating the CB1 receptors on masseter muscle mechanoreceptors to provide analgesic relief without central side effects.

SIGNIFICANCE:

Our results suggest THC could reduce masticatory muscle pain through activating peripheral CB1 receptors. Peripheral application of cannabinoids could be a novel approach to provide analgesic relief without central side effects.”

https://www.ncbi.nlm.nih.gov/pubmed/28722246

http://onlinelibrary.wiley.com/doi/10.1002/ejp.1085/abstract

Antinociceptive effects of HUF-101, a fluorinated cannabidiol derivative.

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“Cannabidiol (CBD) is a phytocannabinoid with multiple pharmacological effects and several potential therapeutic properties. Its low oral bioavailability, however, can limit its clinical use.

Preliminary results indicate that fluorination of the CBD molecule increases its pharmacological potency. Here, we investigated whether HUF-101 (3, 10, and 30mg/kg), a fluorinated CBD analogue, would induce antinociceptive effects.

These findings show that HUF-101 produced antinociceptive effects at lower doses than CBD, indicating that the addition of fluoride improved its pharmacological profile. Furthermore, some of the antinociceptive effects of CBD and HUF-101 effects seem to involve the activation of CB1 and CB2 receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/28720466

http://www.sciencedirect.com/science/article/pii/S0278584617302233

Cannabidiol Is a Potential Therapeutic for the Affective-Motivational Dimension of Incision Pain in Rats.

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“Drugs that interfere with the endocannabinoid system are alternatives for the management of clinical pain. Cannabidiol (CBD), a phytocannabinoid found in Cannabis sativa, has been utilized in preclinical and clinical studies for the treatment of pain. Herein, we evaluate the effects of CBD. The study provides evidence that CBD influences different dimensions of the response of rats to a surgical incision, and the results establish the rostral anterior cingulate cortex (rACC) as a brain area from which CBD evokes antinociceptive effects in a manner similar to the systemic administration of CBD. The present study has shown for the first time that CBD injected either systemically or into the rACC induces a long-lasting anti-allodynic effect with a bell-shaped dose-response curve in a rat model of incision pain.” https://www.ncbi.nlm.nih.gov/pubmed/28680401

Efficacy, tolerability, and safety of non-pharmacological therapies for chronic pain: An umbrella review on various CAM approaches.

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“Complementary and alternative medicine (CAM) therapies may be used as a non-pharmacological approach to chronic pain management. Twenty-six reviews (207 clinical trials, >12,000 participants) about 18 CAM modalities, falling under natural products, mind and body practices or other complementary health approaches were included. Inhaled cannabis, graded motor imagery, and Compound Kushen injection (a form of Chinese medicine) were found the most efficient and tolerable for chronic pain relief. When reported, adverse effects related to these CAM were minor.” https://www.ncbi.nlm.nih.gov/pubmed/28669581

Cannabis as a Substitute for Opioid-Based Pain Medication: Patient Self-Report

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“Prescription drug overdoses are the leading cause of accidental death in the United States. Alternatives to opioids for the treatment of pain are necessary to address this issue. Cannabis can be an effective treatment for pain, greatly reduces the chance of dependence, and eliminates the risk of fatal overdose compared to opioid-based medications. Medical cannabis patients report that cannabis is just as effective, if not more, than opioid-based medications for pain.

The results of this study provide implications from both a micro and macro level. First, from the macro level, there have been three previously published indicators of public health changes in states that permit medical cannabis: decreases in opioid related mortality, decreases in spending on opioids, and a decrease in traffic fatalities. While none of these studies shows a cause and effect relationship, they do suggest public health related population based changes in localities where cannabis can be accessed to treat pain. Given that the participants in this study reported a greater likelihood of using cannabis as a substitute in a less stigmatized and easily accessible environment, it makes sense why we would see these changes in locations where medical cannabis is sanctioned versus places where it is illegal.

At the micro level, there is a great deal of individual risk associated with prolonged use of opioids and perhaps even nonopioid-based pain medications. The prescribing of opioids has not been curbed in the United States, despite the growing number of fatal overdoses and reported dependence. Providing the patient with the option of cannabis as a method of pain treatment alongside the option of opioids might assist with pain relief in a safer environment with less risk. A society with less opioid dependent people will result in fewer public health harms.”

http://online.liebertpub.com/doi/10.1089/can.2017.0012

Cannabinoids could make opioids more effective, meaning pain relief with lower doses and reduced risk of dependency

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“In animal studies, four times less morphine and ten times less codeine was needed when cannabinoids were given at the same time.

The higher the dose of opioid pain relievers, the more likely it is a patient will experience side effects and complications. With the opioid epidemic becoming a pressing problem, researchers are working to find ways to provide pain relief with less risk. To understand whether therapeutic cannabinoids could be an effective strategy to reduce opioid use, researchers at the University of New South Wales and the Centre for Addiction and Mental Health analysed data from 19 pre-clinical studies and nine clinical trials.

“These studies highlight the potential beneficial effects of combining opioids and cannabinoids””

The cannabinoid system and pain.

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“Chronic pain states are highly prevalent and yet poorly controlled by currently available analgesics, representing an enormous clinical, societal, and economic burden. Existing pain medications have significant limitations and adverse effects including tolerance, dependence, gastrointestinal dysfunction, cognitive impairment, and a narrow therapeutic window, making the search for novel analgesics ever more important. In this article, we review the role of an important endogenous pain control system, the endocannabinoid (EC) system, in the sensory, emotional, and cognitive aspects of pain. Herein, we briefly cover the discovery of the EC system and its role in pain processing pathways, before concentrating on three areas of current major interest in EC pain research; 1. Pharmacological enhancement of endocannabinoid activity (via blockade of EC metabolism or allosteric modulation of CB1receptors); 2. The EC System and stress-induced modulation of pain; and 3. The EC system & medial prefrontal cortex (mPFC) dysfunction in pain states. Whilst we focus predominantly on the preclinical data, we also include extensive discussion of recent clinical failures of endocannabinoid-related therapies, the future potential of these approaches, and important directions for future research on the EC system and pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28625720

http://www.sciencedirect.com/science/article/pii/S002839081730285X