Tag Archives: CB1

CB1 cannabinoid receptor signalling in Parkinson’s disease.

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Abstract

“Signalling at CB(1) cannabinoid receptors plays a key role in the control of movement in health and disease. In recent years, an increased understanding of the physiological role of transmission at CB(1) receptors throughout the basal ganglia circuitry has led to the identification of novel therapeutic approaches to both the symptoms of Parkinson’s disease and the side effects of current anti-parkinsonian therapies, especially L(3,4) dihydroxyphenylalamine (levodopa)-induced dyskinesia. Thus, because activation of basal ganglia CB(1) receptors can modulate neurotransmission and contribute to synaptic plasticity in a manner similar to that described in other brain regions, it also appears that endocannabinoids might modulate cell-cell signalling via effects on neurotransmitter re-uptake and postsynaptic actions mediating cross talk between multiple receptor types. Recent studies in animal models and in the clinic suggest that CB(1) receptor antagonists could prove useful in the treatment of parkinsonian symptoms and levodopa-induced dyskinesia, whereas CB(1) receptor agonists could have value in reducing levodopa-induced dyskinesia.”

http://www.ncbi.nlm.nih.gov/pubmed/12550742

Depression in Parkinson’s disease is related to a genetic polymorphism of the cannabinoid receptor gene (CNR1).

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Abstract

“Depression is a common symptom in Parkinson’s disease (PD) and it is present in up to 40% of the patients. The cause of depression in PD is thought to be related to disturbance of monoamine neurotransmission. The endogenous cannabinoid system mediates different brain processes that play a role in the control of behaviour and emotions. Cannabinoid function may be altered in neuropsychiatry diseases, directly or through interactions with monoamine, GABA and glutamate systems. For this reason, we have investigated whether there is a genetic risk factor for depression in PD linked to the polymorphisms of CB1 receptor gene. Depression was more frequent in patients with PD than in controls with osteoarthritis. The presence of depression did not correlate with the stage of the disease but it was more frequent in patients with pure akinetic syndrome than in those with tremoric or mixed type PD. The CB1 receptor gene polymorphism (AAT)n is considered to modify the transcription of the gene and, therefore, it may have functional relevance. We analysed the length of the polymorphic triplet (AAT)n of the gene that encodes CB1 (CNR1) receptor in 89 subjects (48 PD patients and 41 controls). In patients with PD, the presence of two long alleles, with more than 16 repeated AAT trinucleotides in the CNR1 gene, was associated with a reduced prevalence of depression (Fisher’s exact test: P=0.003). This association did not reach significant differences in the control group, but the number of control individuals with depression was too small to allow for statistical analysis. Since the alleles with long expansions may have functional impact in cannabinoid neurotransmission, our data suggest that the pharmacological manipulation of cannabinoid neurotransmission could open a new therapeutic approach for the treatment of depression in PD and possibly in other conditions.”

http://www.ncbi.nlm.nih.gov/pubmed/15668727

Medicinal cannabis extracts for the treatment of multiple sclerosis.

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Abstract

“Prior to 2002, few clinical data were available to indicate whether cannabis extracts may be beneficial. However, in the last two years, results of several placebo-controlled clinical trials of orally administered compounds have been published, and these cast doubt on the efficacy of delta9-tetrahydrocannabinol (delta9-THC) in objectively reducing spasticity in MS. By contrast, it has been claimed that sublingually administered cannabis extracts that contain approximately equal concentrations of delta9-THC and cannabidiol, a natural cannabinoid that does not act on the CB1 receptor, can produce a statistically and clinically significant reduction in spasticity, although this claim has yet to be thoroughly validated. Nonetheless, results of preclinical trials also lend support to the hypothesis that the endogenous cannabinoid system may be involved in the regulation of spasticity and pain. A better indication of the clinical potential of the different cannabis extracts will have to await the publication of the most recent clinical trial data. This review critically evaluates the most recent evidence available on the potential use of medicinal extracts of cannabis to relieve pain and spasticity in multiple sclerosis.”

http://www.ncbi.nlm.nih.gov/pubmed/15298068

Increased expressions of cannabinoid receptor-1 and transient receptor potential vanilloid-1 in human prostate carcinoma.

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“PURPOSE:

Recently, functional cannabinoid receptor-1 (CB1) and vanilloid receptor-1 (TRPV1) have been described in human prostate and prostate cancer-derived cell lines where the activation of the receptors resulted in inhibition of cellular growth. We, however, lack the description of the expression of these molecules in human prostate cancer (PCC) and in benign prostate hyperplasia (BPH).

RESULTS:

CB1 was identified in epithelial and smooth muscle cells types of the human prostate, whereas TRPV1 was exclusively localized to the mucosal cells. We also found that the expression of CB1 and TRPV1 (both at the protein and mRNA levels) were significantly up-regulated in PCC. However, while the increased expression of TRPV1 showed a proper correlation with increasing PCC tumor grades, such phenomenon was not observed with CB1. In addition, we also measured markedly elevated CB1 levels in BPH tissues whilst the expression of TRPV1 was not altered when compared to healthy control prostate.

CONCLUSIONS:

Our findings strongly argue for that (1) the CB1 and TRPV1 molecules as well as their ligands may indeed possess a promising future role in the treatment of PCC; (2) TRPV1 may also serve as a prognostic factor in PCC; and (3) CB1 may act as a potential target molecule in the therapeutic management of BPH.”

http://www.ncbi.nlm.nih.gov/pubmed/18830626

Antidepressant-like effects of Δ⁹-tetrahydrocannabinol and rimonabant in the olfactory bulbectomised rat model of depression.

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Abstract

“The endocannabinoid signalling system is widely accepted to play a role in controlling the affective state. Plant cannabinoids are well known to have behavioural effects in animals and humans and the cannabinoid CB(1) receptor antagonist rimonabant has recently been shown to precipitate depression-like symptoms in clinical trial subjects. The aim of the present study was to investigate the behavioural and neurochemical effects of chronic administration of Δ⁹-tetrahydrocannabinol (THC) and rimonabant on intact and olfactory bulbectomised (OB) rats used as a model of depression. As expected, OB rats were hyperactive in the open field. Repeated THC (2 mg/kg, i.p. once every 48 h for 21 days) and rimonabant (5 mg/kg, i.p. once every 48 h for 21 days) reduced this hyperactivity, which is typical of clinically effective antidepressant drugs. In intact animals, chronic THC increased brain derived neurotrophic factor (BDNF) expression levels in the hippocampus and frontal cortex but rimonabant had no effect. Rimonabant increased the levels of phosphorylated extracellular signal regulated kinases (p-ERKs(1/2)) in the hippocampus and prefrontal cortex and THC also increased expression in frontal cortex. OB did not affect BDNF or p-ERK(1/2) expression in the hippocampus or frontal cortex and in, contrast to the intact animals, neither THC nor rimonabant altered expression in the OB rats. These findings indicate antidepressant-like behavioural properties of both THC and rimonabant in OB rats although additional studies are required to clarify the relationship between the chronic effects of cannabinoids in other pre-clinical models and in human depression.”

http://www.ncbi.nlm.nih.gov/pubmed/22634064

A possible role for the endocannabinoid system in the neurobiology of depression

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“The present review synthetically describes the currently advanced hypotheses for a neurobiological basis of depression, ranging from the classical monoaminergic to the more recent neurotrophic hypothesis. Moreover, the Authors review the available preclinical and clinical evidence suggesting a possible role for the endocannabinoid system in the physiopathology of depression. Indeed, in spite of the reporting of conflicting results, the pharmacological enhancement of endocannabinoid activity at the CB1 cannabinoid receptor level appears to exert an antidepressant-like effect in some animal models of depression. On the contrary, a reduced activity of the endogenous cannabinoid system seems to be associated with the animal model of depression, namely the chronic mild stress model. Moreover, a few studies have reported an interaction of antidepressants with the endocannabinoid system. “

“The endocannabinoid system”

“A detailed description of the endocannabinoid system is beyond the scope of this paper. Thus, in this section we briefly describe those components of the endocannabinoid system that act as targets for the pharmacological interventions aimed at determining the activity of the endocannabinoid system.”

“The term “endocannabinoid system” refers to the recently discovered neuromodulator system comprising cannabinoid receptors (which represent the receptors of Tetrahydrocannabinol (THC), the major active component of cannabis) and their endogenous ligands.”

“To date, two types of cannabinoid receptors have been identified: CB1 and CB2 receptors. These receptors belong to the superfamily of G protein coupled receptors, the CB1 receptor is widely distributed in the terminals of neurons, while the CB2 receptor is extensively expressed throughout the immune system. However, it has recently been reported that these receptors are present also in the brain.”

“No clinical trials carried out using cannabinoids in the treatment of affective disorders have been published to date, although anecdotal reports have described both antidepressant and antimanic properties of cannabis.”

“Indeed, pharmacological manipulations of the endocannabinoid system have elicited antidepressant-like effects in animal models of depression. Moreover, some animal models of depression seem to be associated to alterations in the endocannabinod system.”

“Although no clinical trials performed using cannabinoids in the treatment of affective disorders have been published to date, anecdotal reports have described both antidepressant and antimanic properties of cannabis”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2169225/

Role of the endocannabinoid system in depression and suicide.

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“Depression is one of the most prevalent forms of neuropsychiatric disorder and is a major cause of suicide worldwide. The prefrontal cortex is a crucial brain region that is thought to be involved in the regulation of mood, aggression and/or impulsivity and decision making, which are altered in suicidality.

Evidence of the role of the endocannabinoid (EC) system in the neurobiology of neuropsychiatric disorders is beginning to emerge. The behavioral effects of ECs are believed to be mediated through the central cannabinoid CB1 receptor. Alterations in the levels of ECs, and in the density and coupling efficacy of CB1 receptors, have been reported in the prefrontal cortex of depressed and alcoholic suicide victims.

These findings support our hypothesis that altered EC function contributes to the pathophysiological aspects of suicidal behavior. Here, we provide a brief overview of the role of the EC system in alcoholism, depression and suicide, and discuss possible therapeutic interventions and directions for future research.”

https://www.ncbi.nlm.nih.gov/pubmed/16919786

http://www.cell.com/trends/pharmacological-sciences/fulltext/S0165-6147(06)00186-6

 

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

 

Cannabinoid type-1 receptor reduces pain and neurotoxicity produced by chemotherapy

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 “Painful peripheral neuropathy is a dose-limiting complication of chemotherapy. Cisplatin produces a cumulative toxic effect on peripheral nerves…”

 

“Cannabinoid type-1 receptor reduces pain and neurotoxicity produced by chemotherapy”

 

“Clinically, the synthetic cannabinoid agonist nabilone reduces chemotherapy-induced pain”

 

“Like synthetic CB1R agonists, AEA attenuates hyperalgesia in models of neuropathic, inflammatory and tumor pain.”

 

“Collectively, these results suggest that pharmacological facilitation of AEA signaling is a promising strategy for attenuating cisplatin-associated sensory neuropathy.”

 

“Conclusion

We have shown that cisplatin produces hyperalgesia and toxicity to sensory neurons as indicated by neurochemical, morphological and functional measures. Increasing AEA signaling at CB1 receptors not only reduced the hyperalgesia but reduced the neurotoxicity of cisplatin as well. Although the mechanisms by which AEA reduce neurotoxicity remain to be resolved, the present studies underscore the dual utility in exploiting the endocannabinoid system for management of neuropathic pain produced by chemotherapy.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3366638/

Abnormal mGlu 5 Receptor/Endocannabinoid Coupling in Mice Lacking FMRP and BC1 RNA

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“Transcriptional silencing of the gene encoding the fragile X mental retardation protein (FMRP) causes fragile X syndrome (FXS)…

Our data indicate for the first time that mGlu5R-driven endocannabinoid signaling in the striatum is under the control of both FMRP and BC1 RNA. The abnormal mGlu5R/2-AG coupling found in FMRP-KO mice emphasizes the involvement of mGlu5Rs in the synaptic defects of FXSand identifies the modulation of the endocannabinoid system as a novel target for the treatment of this severe neuropsychiatric disorder.

In conclusion, this is the first study addressing endocannabinoid system in a model of FXS. Our results show that dysfunctional mGlu5R signaling leads to abnormal 2-AG metabolism and physiological activity, and indicate that inhibition of 2-AG synthesis or activity at CB1Rs might be a useful treatment option in FXS patients. In this respect, recent investigations suggest that this modulation could be achieved not only by direct pharmacological blockade of CB1Rs, but also indirectly, for example through the inhibition of anandamide degradation or the stimulation of transient receptor potential vanilloid 1 (TRPV1) channels. These two components of the endocannabinoid system, in fact, have been shown to selectively interact with mGlu5R/2-AG coupling in striatal neurons, and might interfere with the synaptic alterations seen after FMRP ablation with less side effects than those of widespread pharmacological inhibition of CB1Rs, which control not only GABA but also glutamate synapses.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3055456/