Endocannabinoid mechanism in amphetamine-type stimulant use disorders: A short review.

Journal of Clinical Neuroscience Home

“Recent evidence shows that the endocannabinoid system is involved in amphetamine-type stimulants (ATS) use disorders. To elucidate the role of the endocannabinoid system in ATS addiction, we reviewed results of studies using cannabinoid receptor agonists, antagonists as well as knockout model.

The endocannabinoid system seems to play a role in reinstatement and relapse of ATS addiction and ATS-induced psychiatric symptoms. The molecular mechanisms of this system remains unclear, the association with dopamine system in nucleus accumbens is most likely involved. However, the function of the endocannabinoid system in anxiety and anti-anxiety effects induced by ATS is more complicated.

These findings suggest that the endocannabinoid system may play an important role in the mechanism of ATS addiction and provide new idea for treating ATS addiction.”

https://www.ncbi.nlm.nih.gov/pubmed/28912087

http://www.jocn-journal.com/article/S0967-5868(17)30989-X/fulltext

The FAAH inhibitor URB597 suppresses hippocampal maximal dentate afterdischarges and restores seizure-induced impairment of short and long-term synaptic plasticity.

“Synthetic cannabinoids and phytocannabinoids have been shown to suppress seizures both in humans and experimental models of epilepsy.

However, they generally have a detrimental effect on memory and memory-related processes. Here we compared the effect of the inhibition of the endocannabinoid (eCB) degradation versus synthetic CB agonist on limbic seizures induced by maximal dentate activation (MDA) acute kindling. Moreover, we investigated the dentate gyrus (DG) granule cell reactivity and synaptic plasticity in naïve and in MDA-kindled anaesthetised rats.

We found that both the fatty acid amide hydrolase (FAAH) inhibitor URB597 and the synthetic cannabinoid agonist WIN55,212-2 displayed AM251-sensitive anti-seizure effects. WIN55,212-2, dose-dependently (0.5-2 mg/kg, i.p.) impaired short-term plasticity (STP) and long-term potentiation (LTP) at perforant path-DG synapses in naïve rats. Strikingly, URB597 (1 mg/kg, i.p.) was devoid of any deleterious effects in normal conditions, while it prevented seizure-induced alterations of both STP and LTP.

Our evidence indicates that boosting the eCB tone rather than general CB1 activation might represent a potential strategy for the development of a new class of drugs for treatment of both seizures and comorbid memory impairments associated with epilepsy.”

https://www.ncbi.nlm.nih.gov/pubmed/28894217

https://www.nature.com/articles/s41598-017-11606-1

[Cannabis use in Epilepsy. Current situation in Argentina and abroad].

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“Although at present we have over 20 different types of drugs for epilepsy, 30 to 40% of patients continue to have seizures.

Preliminary data from human studies suggest that cannabis, cannabidiol in particular, is effective in the treatment of some patients with epilepsy.

However, the available data are limited and do not allow defnitive conclusions. Only randomized clinical trials with controlled double-blind, placebo-controlled utilizing secure preparations and one or more cannabinoids, will provide comprehensive information on the effcacy and safety of use.

In order to perform these trials it is necessary to have legislation authorizing the use of cannabis on epilepsy.”

Effects of coadministration of low dose cannabinoid type 2 receptor agonist and morphine on vanilloid receptor 1 expression in a rat model of cancer pain.

“Morphine is widely used as an analgesic to treat moderate to severe pain, but chronic morphine use is associated with development of tolerance and dependence, which limits its analgesic efficacy. Our previous research has showed that nonanalgetic dose of a cannabinoid type 2 (CB2) receptor agonist reduced morphine tolerance in cancer pain. A previous study showed the colocalization of CB2 and transient receptor potential vanilloid 1 (TRPV1) in human and rat dorsal root ganglia (DRG) sensory neurons. Whether coadministration of a CB2 receptor agonist and morphine could reduce TRPV1 expression in morphine‑induced antinociception and tolerance in cancer pain is unclear. Therefore, we investigated the effects of coadministration of a CB2 receptor agonist AM1241 and morphine on TRPV1 expression and tolerance in cancer pain. Coadministration of AM1241 and morphine for 8 days significantly reduced morphine tolerance, as assessed by measuring paw withdrawal latency to a radiant heat stimulation, in Walker 256 tumor‑bearing rats. Repeated morphine treatment for a period of 8 days induced upregulation of the TRPV1 protein expression levels in the DRG in the tumor‑bearing rats, although no change in mRNA expression. Pretreatment with AM1241 reduced this morphine‑induced upregulation of TRPV1 and the effect was reversed by the CB2 receptor antagonist AM630. Our findings suggest that coadministration of a CB2 receptor agonist AM1241 and morphine reduced morphine tolerance possibly through regulation of TRPV1 protein expression in the DRG in cancer pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28901432

https://www.spandidos-publications.com/10.3892/mmr.2017.7479

Cannabis constituent synergy in a mouse neuropathic pain model.

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“Cannabis and its psychoactive constituent Δ9-tetrahydrocannabinol (THC) have efficacy against neuropathic pain however, this is hampered by their side-effects. It has been suggested that co-administration with another major constituent cannabidiol (CBD) might enhance the analgesic actions of THC and minimise its deleterious side-effects.

We examined the basis for this phytocannabinoid interaction in a mouse chronic constriction injury (CCI) model of neuropathic pain. Acute systemic administration of THC dose-dependently reduced CCI-induced mechanical and cold allodynia, but also produced motor incoordination, catalepsy and sedation. CBD produced a lesser dose-dependent reduction in allodynia, but did not produce the cannabinoid side-effects. When co-administered in a fixed ratio, THC and CBD produced a biphasic dose-dependent reduction in allodynia. At low doses, the THC:CBD combination displayed a 200-fold increase in anti-allodynic potency, but had lower efficacy compared to that predicted for an additive drug interaction. By contrast, high THC:CBD doses had lower potency, but greater anti-allodynic efficacy compared to that predicted for an additive interaction. Only the high dose THC:CBD anti-allodynia was associated with cannabinoid side-effects and these were similar to those of THC alone. Unlike THC, the low dose THC:CBD anti-allodynia was not cannabinoid receptor mediated.

These findings demonstrate that CBD synergistically enhances the pain relieving actions of THC in an animal neuropathic pain model, but has little impact on the THC-induced side-effects. This suggests that low dose THC:CBD combination treatment has potential in the treatment of neuropathic pain.”

Anti-nociceptive interactions between opioids and a cannabinoid receptor 2 agonist in inflammatory pain.

SAGE Journals

“The cannabinoid 1 receptor and cannabinoid 2 receptor can both be targeted in the treatment of pain; yet, they have some important differences. Cannabinoid 1 receptor is expressed at high levels in the central nervous system, whereas cannabinoid 2 receptor is found predominantly, although not exclusively, outside the central nervous system. The objective of this study was to investigate potential interactions between cannabinoid 2 receptor and the mu-opioid receptor in pathological pain. The low level of adverse side effects and lack of tolerance for cannabinoid 2 receptor agonists are attractive pharmacotherapeutic traits. This study assessed the anti-nociceptive effects of a selective cannabinoid 2 receptor agonist (JWH-133) in pathological pain using mice subjected to inflammatory pain using the formalin test. Furthermore, we examined several ways in which JWH-133 may interact with morphine. JWH-133 produces dose-dependent anti-nociception during both the acute and inflammatory phases of the formalin test. This was observed in both male and female mice. However, a maximally efficacious dose of JWH-133 (1 mg/kg) was not associated with somatic withdrawal symptoms, motor impairment, or hypothermia. After eleven once-daily injections of 1 mg/JWH-133, no tolerance was observed in the formalin test. Cross-tolerance for the anti-nociceptive effects of JWH-133 and morphine were assessed to gain insight into physiologically relevant cannabinoid 2 receptor and mu-opioid receptor interaction. Mice made tolerant to the effects of morphine exhibited a lower JWH-133 response in both phases of the formalin test compared to vehicle-treated morphine-naïve animals. However, repeated daily JWH-133 administration did not cause cross-tolerance for morphine, suggesting opioid and cannabinoid 2 receptor cross-tolerance is unidirectional. However, preliminary data suggest co-administration of JWH-133 with morphine modestly attenuates morphine tolerance. Isobolographic analysis revealed that co-administration of JWH-133 and morphine has an additive effect on anti-nociception in the formalin test. Overall these findings show that cannabinoid 2 receptor may functionally interact with mu-opioid receptor to modulate anti-nociception in the formalin test.”

https://www.ncbi.nlm.nih.gov/pubmed/28879802

http://journals.sagepub.com/doi/10.1177/1744806917728227

 

Managing neuropathic pain in multiple sclerosis: Pharmacological interventions.

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“Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Of the plethora of motor and sensory disturbances experienced by sufferers, neuropathic pain is a highly prevalent and debilitating symptom, and at present remains extremely difficult to treat. Common forms of neuropathic pain seen in MS patients include central neuropathic pain, Lhermitte’s phenomenon and trigeminal neuralgia, which are all speculated to arise from specific patterns of lesion formation.

OBJECTIVE:

Efficacious pharmacological interventions for the treatment of neuropathic pain associated with MS are lacking, and have been largely informed by drug trials in peripheral neuropathies and spinal cord injury.

METHOD/RESULTS:

Neuropathic pain in MS is inadequately relieved by conventional analgesics, and first-line therapies are generally comprised of anti-depressive and anti-convulsive drugs. A range of alternatives have been proposed and tested with variable success, including cannabinoids and certain opioid analgesics. Animals with experimental autoimmune encephalomyelitis (EAE), an autoimmune model of MS, also exhibit neuropathic pain symptoms.

CONCLUSION:

Studies aimed at understanding the mechanisms underlying EAE-induced neuropathic pain and investigating the efficacy of novel pharmacological interventions at the animal level offer an exciting area of future research, and may inform future therapeutic options for MS-associated neuropathic pain.”

https://www.ncbi.nlm.nih.gov/pubmed/28875858

 

Mechanisms of action of cannabidiol in adoptively transferred experimental autoimmune encephalomyelitis.

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“Cannabidiol (CBD) is one of the most important compounds in Cannabis sativa, lacks psychotropic effects, and possesses a high number of therapeutic properties including the amelioration of experimental autoimmune encephalomyelitis (EAE).

The aim of this study was to analyse the relative efficacy of CBD in adoptively transferred EAE (at-EAE), a model that allows better delineation of the effector phase of EAE.

Preventive intraperitoneal treatment with CBD ameliorated the clinical signs of at-EAE. CBD markedly improved the clinical signs of at-EAE and reduced infiltration, demyelination and axonal damage. The CBD-mediated decrease in the viability of encephalitogenic cells involves ROS generation, apoptosis and a decrease in IL-6 production and may contribute to the therapeutic effect of this compound.”

https://www.ncbi.nlm.nih.gov/pubmed/28867485

http://www.sciencedirect.com/science/article/pii/S0014488617302212

Systematic Review of the Costs and Benefits of Prescribed Cannabis-Based Medicines for the Management of Chronic Illness: Lessons from Multiple Sclerosis.

PharmacoEconomics

“Cannabis-based medicines (CBMs) may offer relief from symptoms of disease; however, their additional cost needs to be considered alongside their effectiveness. We sought to review the economic costs and benefits of prescribed CBMs in any chronic illness, and the frameworks used for their economic evaluation.

CONCLUSIONS:

Prescribed CBMs are a potentially cost-effective add-on treatment for MS spasticity; however, this evidence is uncertain. Further investment in randomised trials with in-built economic evaluations is warranted for a wider range of clinical indications.”

https://www.ncbi.nlm.nih.gov/pubmed/28866778

https://link.springer.com/article/10.1007%2Fs40273-017-0565-6

CHANGES IN THE CANNABINOIDS RECEPTORS IN RATS FOLLOWING TREATMENT WITH ANTIDEPRESSANTS.

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“The endocannabinoid (eCB) system plays a significant role in the pathophysiology of depression. The potential participation of this system in the mechanism of action of antidepressants has been highlighted in recent years.

The aim of this study was to investigate the expression of cannabinoid (CB) receptors using Western blot and CB1 receptor density using autoradiography after acute or chronic administration of antidepressant drugs [imipramine (IMI, 15mg/kg), escitalopram (ESC, 10mg/kg) and tianeptine (TIA, 10mg/kg)].

Antidepressants given chronically elevated CB1 receptor density in the cortical structures and hippocampal areas, while a decrease of CB1 receptor density was observed in the striatum after IMI and ESC treatment. The CB1 receptor expression decreases in the dorsal striatum after chronic administration of IMI and ESC or the receptor rise in the hippocampus after chronic ESC and TIA treatment were confirmed using Western blot analyses. An increase in the CB2 receptor expression was observed in the cortical structures and hippocampus after chronic administration of ESC and TIA, while a decrease in this expression was noted in the striatum and cerebellum after chronic IMI treatment.

Our results provide clear evidence that the antidepressant exposures provoke some modulations within the eCB system through CB receptors.”

https://www.ncbi.nlm.nih.gov/pubmed/28866072

http://www.sciencedirect.com/science/article/pii/S0161813X17301717