Tag Archives: agonists

Self-medication of a cannabinoid CB2 agonist in an animal model of neuropathic pain.

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“Neuropathic pain is caused by injury to the peripheral or central nervous system (CNS)…”

“…novel approaches for identifying safe and effective analgesics with limited abuse liability are necessary.”

“Cannabinoids share the same target as the psychoactive ingredient in maijuana. Cannabinoids suppress neuropathic nociception through CB1 and CB2 mechanisms. CB1 is predominantly located within the CNS… CB2 activation is not associated with CNS side-effects linked to CB1. However, abuse potential of CB2 agonists is unknown.”

“We used a drug self-administration approach to ask whether rats with a spared nerve injury (SNI) would self-medicate with a CB2 agonist to attenuate a neuropathic pain state…”

 “Our results suggest that cannabinoid CB2 agonists may be exploited to treat neuropathic pain with limited drug abuse liability and central nervous system (CNS) side-effects. These studies validate the use of drug self-administration methods for identifying nonpsychotropic analgesics possessing limited abuse potential…”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3157548/

Whole plant cannabis extracts in the treatment of spasticity in multiple sclerosis: a systematic review.

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“Spasticity, an involuntary increase in muscle tone or rapid muscle contractions, is one of the more common and distressing symptoms of multiple sclerosis (MS). Medicinal treatment may reduce spasticity, but may also be ineffective, difficult to obtain, or associated with intolerable side effects. Cannabis, a psychotropic drug known for its analgesic properties, also has a long history as an effective and tolerable treatment for spasticity]. Demographic evidence has shown that many people with MS use cannabis for symptom management.

Clinical studies, animal models, and anecdotal reports have suggested that cannabis may be an effective treatment of MS spasticity. The antispastic effect of cannabis has been supported through a demonstration of the inhibitory properties in exogenous agonists for cannabis receptors found in the CNS. Early clinical trials reporting the efficacy and safety of cannabis use in MS have focused on the effects of Δ9-tetrahydrocannabinol (THC). Although these clinical studies reported a therapeutic benefit for MS symptoms, there were concerns of potential intoxication and other side effects of cannabis-based treatment. Another clinical study using a cannabidiol (CBD) extract documented a reduction in spasticity-related pain but not in spasticity..

More recent combination therapies using whole plant extracts of both THC and CBD have been introduced and there is evidence that CBD, which is not psychotropic, may reduce THC levels in the brain and attenuate its psychotropic side effects. Such therapies may potentially provide a tolerable yet effective treatment for MS symptoms. A number of recent studies have investigated the potential efficacy and safety of whole plant extracts of THC and CBD. One of the first large-scale studies of cannabis treatment for MS-related spasticity compared whole plant cannabis extracts with THC and a placebo, and found mixed evidence for the therapeutic benefit of spasticity in MS. A recent review that included a number of these recent studies provided additional support for the benefit of cannabinoids in MS-related spasticity but called for further study into long-term treatment and side effects. A systematic evaluation of recent research had not previously been conducted, and was needed in order to provide organized evidence of cannabinoid treatments and direction for future clinical studies. We therefore systematically reviewed studies that used a combination extract of THC and CBD for the treatment of spasticity.

We found evidence that combined THC and CBD extracts may provide therapeutic benefit for MS spasticity symptoms…

Finally, there is evidence that cannabinoids may provide neuroprotective and anti-inflammatory benefits in MS. Neuroinflammation, found in autoimmune diseases such as MS, has been shown to be reduced by cannabinoids through the regulation of cytokine levels in microglial cells. The therapeutic potential of cannabinoids in MS is therefore comprehensive and should be given considerable attention.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2793241/

Cannabinoid Receptor as a Novel Target for the Treatment of Prostate Cancer

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“Because prostate cancer has become the most common cancer diagnosed in men, developing novel targets and mechanism-based agents for its treatment has become a challenging issue. In recent years cannabinoids, the active components of Cannabis sativa Linnaeus (marijuana) and their derivatives have drawn renewed attention because of their diverse pharmacologic activities such as cell growth inhibition, anti-inflammatory effects, and tumor regression . Cannabinoids have been shown to induce apoptosis in gliomas, PC-12 pheochromocytoma, CHP 100 neuroblastoma, and hippocampal neurons in vitro, and most interestingly, regression of C6-cell gliomas in vivo. Further interest in cannabinoid research came from the discovery of specific cannabinoid systems and the cloning of specific cannabinoid receptors. These diversified effects of cannabinoids are now known to be mediated by the activation of specific G protein-coupled receptors that are normally bound by a family of endogenous ligands, the endocannabinoids. Two different cannabinoid receptors have been characterized and cloned from mammalian tissues: the “central” CB1 receptor, and the “peripheral” CB2 receptor.”

“In the present study, we show for the first time that expression levels of both cannabinoid receptors, CB1 and CB2, are higher in human prostate cancer cells than in normal cells. Importantly, we also show that WIN-55,212-2 (CB1/CB2 agonist) treatment with androgen-responsive LNCaP cells results in a dose- and time-dependent inhibition of cell growth with a concomitant induction of apoptosis, decrease in protein and mRNA expression of androgen receptor and prostate-specific antigen (PSA), decrease in secreted PSA levels, protein expression of proliferating cell nuclear antigen (PCNA), and vascular endothelial growth factor (VEGF). We suggest that cannabinoid receptor agonists may be useful in the treatment of human prostate cancer.”

“…non–habit-forming cannabinoid receptor agonists could be developed as novel therapeutic agents for the treatment of prostate cancer.”

“We conclude that cannabinoids should be considered as agents for the management of prostate cancer.”

.http://cancerres.aacrjournals.org/content/65/5/1635.long

Delta9-tetrahydrocannabinol induces apoptosis in human prostate PC-3 cells via a receptor-independent mechanism.

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Abstract

“The effect of delta9-tetrahydrocannabinol (THC), the major psycho-active component of marijuana, in human prostate cancer cells PC-3 was investigated. THC caused apoptosis in a dose-dependent manner. Morphological and biochemical changes induced by THC in prostate PC-3 cells shared the characteristics of an apoptotic phenomenon. First, loss of plasma membrane asymmetry determined by fluorescent anexin V binding. Second, presence of apoptotic bodies and nuclear fragmentation observed by DNA staining with 4′,6-diamino-2-phenylindole (DAPI). Third, presence of typical ‘ladder-patterned’ DNA fragmentation. Central cannabinoid receptor expression was observed in PC-3 cells by immunofluorescence studies. However, several results indicated that the apoptotic effect was cannabinoid receptor-independent, such as lack of an effect of the potent cannabinoid agonist WIN 55,212-2, inability of cannabinoid antagonist AM 251 to prevent cellular death caused by THC and absence of an effect of pertussis toxin pre-treatment.”

http://www.ncbi.nlm.nih.gov/pubmed/10570948

Neuroprotective effects of phytocannabinoid-based medicines in experimental models of Huntington’s disease.

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Abstract

“We studied whether combinations of botanical extracts enriched in either Δ(9)-tetrahydrocannabinol (Δ(9)-THC) or cannabidiol (CBD), which are the main constituents of the cannabis-based medicine Sativex, provide neuroprotection in rat models of Huntington’s disease (HD). We used rats intoxicated with 3-nitropropionate (3NP) that were given combinations of Δ(9)-THC- and CBD-enriched botanical extracts. The issue was also studied in malonate-lesioned rats. The administration of Δ(9)-THC- and CBD-enriched botanical extracts combined in a ratio of 1:1 as in Sativex attenuated 3NP-induced GABA deficiency, loss of Nissl-stained neurons, down-regulation of CB(1) receptor and IGF-1 expression, and up-regulation of calpain expression, whereas it completely reversed the reduction in superoxide dismutase-1 expression. Similar responses were generally found with other combinations of Δ(9)-THC- and CBD-enriched botanical extracts, suggesting that these effects are probably related to the antioxidant and CB(1) and CB(2) receptor-independent properties of both phytocannabinoids. In fact, selective antagonists for both receptor types, i.e., SR141716 and AM630, respectively, were unable to prevent the positive effects on calpain expression caused in 3NP-intoxicated rats by the 1:1 combination of Δ(9)-THC and CBD. Finally, this combination also reversed the up-regulation of proinflammatory markers such as inducible nitric oxide synthase observed in malonate-lesioned rats. In conclusion, this study provides preclinical evidence in support of a beneficial effect of the cannabis-based medicine Sativex as a neuroprotective agent capable of delaying disease progression in HD, a disorder that is currently poorly managed in the clinic, prompting an urgent need for clinical trials with agents showing positive results in preclinical studies.”

http://www.ncbi.nlm.nih.gov/pubmed/21674569

The endocannabinoid system as a target for novel anxiolytic and antidepressant drugs.

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“Observational studies in humans suggest that exposure to marijuana and other cannabis-derived drugs produces a wide range of subjective effects on mood tone and emotionality. These observations have their counterpart in animal studies, showing that cannabinoid agonists strongly affect emotional reactivity in directions that vary depending on dose and context. Based on these evidence, the activation of central CB(1) receptor has emerged as potential target for the development of antianxiety and antidepressant therapies…”

http://www.ncbi.nlm.nih.gov/pubmed/19607961

 

Intrathecal Administration of the Cannabinoid 2 Receptor Agonist JWH015 Can Attenuate Cancer Pain and Decrease mRNA Expression of the 2B Subunit of N-Methyl-d-Aspartic Acid

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“Pain has a negative impact on the quality of life in cancer patients…

…we hypothesized that a cannabinoid receptor agonist might be a novel therapy for cancer pain. Taking into consideration the side effects of a CB1 receptor agonist (which limits their clinical application), we chose a CB2 receptor agonist to investigate its effect in cancer pain…

 Recent clinical trials have demonstrated that cannabinoids may have significant positive effects in refractory chronic and cancer pain. The cannabinoids are thought to exert most of their effects by binding to G protein–coupled cannabinoid receptors, which include 2 cloned metabotropic receptors: cannabinoid (CB)1 and CB2…

CONCLUSION: These data indicated that intrathecal administration of cannabinoid receptor agonists might relieve cancer pain… These results also suggested that cannabinoids might be a useful alternative or adjunct therapy for relieving cancer pain.

The use of a CB2 receptor agonist could be a novel option for treatment of cancer pain.”

 

 http://www.anesthesia-analgesia.org/content/113/2/405.long

Spinal and peripheral analgesic effects of the CB2 cannabinoid receptor agonist AM1241 in two models of bone cancer-induced pain

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“…a great body of evidence demonstrates the analgesic efficacy of systemically administered CB2 agonists in acute and chronic experimental pain….

The activation of CB2 receptors induces analgesia in experimental models of chronic pain. The present experiments were designed to study whether the activation of peripheral or spinal CB2 receptors relieves thermal hyperalgesia and mechanical allodynia in two models of bone cancer pain.

Conclusions and implications:

Spinal CB2 receptors are involved in the antiallodynic effect… in two neoplastic models while peripheral and spinal receptors participate in the antihyperalgesic effects… The use of drugs that activate CB2 receptors could be a useful strategy to counteract bone cancer-induced pain symptoms.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2931557/

 

A cannabinoid 2 receptor agonist attenuates bone cancer-induced pain and bone loss

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“CB2 agonists not only produce antinociceptive and anti-inflammatory effects, but also have been shown to increase bone density.”

“Recent reports suggest that sustained opiates can produce paradoxical hyperalgesic actions and enhance bone destruction in a murine model of bone cancer. In contrast, CB(2) selective agonists have been shown to reduce bone loss associated with a model of osteoporosis. Here we tested whether a CB(2) agonist administered over a 7day period inhibits bone cancer-induced pain as well as attenuates cancer-induced bone degradation.”

“Based on the antihyperalgesic effects of CB2 agonists, the lack of potential CNS-induced side effects and their propensity to stimulated bone growth, we addressed whether the sustained selective CB2 agonists…  has the potential to alleviate bone cancer-induced pain while maintaining bone integrity in a murine model of bone cancer”.

“These findings suggest a novel therapy for cancer-induced bone pain, bone loss and bone fracture while lacking many unwanted side effects seen with current treatments for bone cancer pain.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871326/

 

CB1 and CB2 receptor agonists promote analgesia through synergy in a murine model of tumor pain

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“Pain associated with cancer and tumor growth is often difficult to manage.”

“Cannabis sativa has a long history of use for management of pain.”

“In light of the adverse side effects of opioids, cannabinoid (CB) receptor agonists may provide an effective alternative for the treatment of cancer pain. The present study examined the potency and efficacy of synthetic CB1 and CB2 receptor agonists in a murine model of tumor pain.”

“Co-administering both CB receptor agonists attenuated mechanical hyperalgesia through a synergistic mechanism.”

 

“Together these data support the use of combined CB1 and CB2 receptor agonists in the development of strategies for the treatment of tumor related pain.”

“These data extend our previous findings that the peripheral cannabinoid receptors are a promising target for the management of cancer pain and mixed cannabinoid receptor agonists may have a therapeutic advantage over selective agonists.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3155626/