Tag Archives: CB(1) and CB(2) receptors

Cannabinoid CB2 receptors and fatty acid amide hydrolase are selectively overexpressed in neuritic plaque-associated glia in Alzheimer’s disease brains.

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.”We have studied the status of some of the components of the endocannabinoid system, fatty acid amide hydrolase and cannabinoid CB1 and CB2 receptors, in postmortem brains from patients with Alzheimer’s disease. Our results show that both fatty acid amide hydrolase and cannabinoid CB2 receptors are abundantly and selectively expressed in neuritic plaque-associated astrocytes and microglia, respectively, whereas the expression of CB1 receptors remains unchanged. In addition, the hydrolase activity seems to be elevated in the plaques and surrounding areas.

Thus, some elements of the endocannabinoid system may be postulated as possible modulators of the inflammatory response associated with this neurodegenerative process and as possible targets for new therapeutic approaches.

To our knowledge, this report is the first evidence for the presence of CB2 receptors in the human CNS. Furthermore, these receptors have recently been reported to play an important role in microglial migration. It is important to note that we detected CB2 receptors only in microglial cells, which is in agreement with the well known immunomodulatory effects of CB2 activation. Thus, many studies have shown that CB2 receptor activation leads to a myriad of changes in the production of inflammation-related substances, although with results that vary depending on the experimental model used and the concentration of cannabinoids used.

 In any case, the selective presence of CB2 receptors in microglial cells opens new perspectives on the role of CB2 receptors in the human CNS and suggests that the modulation of their activity may have therapeutic implications.”

http://www.jneurosci.org/content/23/35/11136.long

The activation of cannabinoid CB2 receptors stimulates in situ and in vitro beta-amyloid removal by human macrophages.

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“The endocannabinoid system is a promising therapeutic target in a wide variety of diseases. However, the non-desirable psychotropic effects of natural and synthetic cannabinoids have largely counteracted their clinical usefulness. These effects are mostly mediated by cannabinoid receptors of the CB(1) type, that exhibit a wide distribution in neuronal elements of the CNS. Thus, the presence of other elements of this system in the CNS, such as CB(2) receptors, may open new possibilities for the development of cannabinoid-based therapies. These receptors are almost absent from the CNS in normal conditions but are up-regulated in glial cells under chronic neuroinflammatory stimuli, as has been described in Alzheimer’s disease. To understand the functional role of these receptors, we tested their role in the process of beta-amyloid removal, that is currently considered as one of the most promising experimental approaches for the treatment of this disease.

Our results show that a CB(2) agonist (JWH-015) is capable of inducing the removal of native beta-amyloid removal from human frozen tissue sections as well as of synthetic pathogenic peptide by a human macrophage cell line (THP-1). Remarkably, this effect was achieved at low doses and was specific for this type of cells, as U373MG astrocytoma cells did not respond to the treatment. The effect was CB(2)-mediated, at least partially, as the selective CB(2) antagonist SR144528 prevented the JWH-015-induced plaque removal in situ.

 These data corroborate the possible therapeutic interest of CB(2) cannabinoid specific chemicals in the treatment of Alzheimer’s disease.”

http://www.ncbi.nlm.nih.gov/pubmed/19505450

CB(2) receptor and amyloid pathology in frontal cortex of Alzheimer’s disease patients.

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“The cannabinoid system seems to play an important role in various neurodegenerative diseases including Alzheimer’s disease (AD). The relationship of cannabinoid receptors (CB(1)R and CB(2)R) to cognitive function and neuropathological markers in AD remains unclear. In the present study, postmortem cortical brain tissues (Brodmann area 10) from a cohort of neuropathologically confirmed AD patients and age-matched controls were used to measure CB(1)R and CB(2)R by immunoblotting. Correlational analyses were performed for the neurochemical and cognitive data. CB(1)R expression was significantly decreased in AD. Levels of CB(1)R correlated with hypophagia, but not with any AD molecular marker or cognitive status (Mini Mental State Examination score). The level of CB(2)R was significantly higher (40%) in AD. Increases in the expression of the glial marker glial fibrillar acidic protein were also found. CB(2)R expression did not correlate with cognitive status. Interestingly, expression levels of CB(2)R correlated with two relevant AD molecular markers, Aβ(42) levels and senile plaque score.

These results may constitute the basis of CB(2)R-based therapies and/or diagnostic approaches.”

http://www.ncbi.nlm.nih.gov/pubmed/22763024

Cannabinoid CB2 receptors in human brain inflammation.

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“CB2 receptors in neuroinflammatory conditions of the human brain.

“CB2 receptors have been found to be present in the CNS, thus offering new opportunities for the pharmacological use of cannabinoid agents. Furthermore, the fact that their expression is increased by inflammatory stimuli suggests that they may be involved in the pathogenesis and/or in the endogenous response to injury. Data obtained in vitro and in animal models show that CB2 receptors may be part of the general neuroprotective action of the ECS…

The anti-inflammatory effects triggered by the activation of the CB2 receptor make it an attractive target for the development of novel anti-inflammatory therapies.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219537/

Endocannabinoid system: emerging role from neurodevelopment to neurodegeneration.

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“The endocannabinoid system, including endogenous ligands (‘endocannabinoids’ ECs), their receptors, synthesizing and degrading enzymes, as well as transporter molecules, has been detected from the earliest stages of embryonic development and throughout pre- and postnatal development. ECs are bioactive lipids, which comprise amides, esters and ethers of long chain polyunsaturated fatty acids. Anandamide (N-arachidonoylethanolamine; AEA) and 2-arachidonoylglycerol (2-AG) are the best studied ECs, and act as agonists of cannabinoid receptors.

Thus, AEA and 2-AG mimic several pharmacological effects of the exogenous cannabinoid delta9-tetrahydrocannabinol (Delta(9)-THC), the psychoactive principle of cannabis sativa preparations like hashish and marijuana. Recently, however, several lines of evidence have suggested that the EC system may play an important role in early neuronal development as well as a widespread role in neurodegeneration disorders. Many of the effects of cannabinoids and ECs are mediated by two G protein-coupled receptors (GPCRs), CB1 and CB2, although additional receptors may be implicated. Both CB1 and CB2 couple primarily to inhibitory G proteins and are subject to the same pharmacological influences as other GPCRs. This new system is briefly presented in this review, in order to put in a better perspective the role of the EC pathway from neurodevelopment to neurodegenerative disorders, like Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and multiple sclerosis.

In addition, the potential exploitation of antagonists of CB1 receptors, or of inhibitors of EC metabolism, as next-generation therapeutics is discussed.”

http://www.ncbi.nlm.nih.gov/pubmed/19356123

Cannabidiol and other cannabinoids reduce microglial activation in vitro and in vivo: relevance to Alzheimer’s disease.

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“Microglial activation is an invariant feature of Alzheimer’s disease (AD). It is noteworthy that cannabinoids are neuroprotective by preventing β-amyloid (Aβ)-induced microglial activation both in vitro and in vivo… the phytocannabinoid cannabidiol (CBD) has shown anti-inflammatory properties in different paradigms…

Cannabinoids, whether plant-derived, synthetic, or endocannabinoids, exert their functions through activation of cannabinoid receptors, two of which have been well characterized to date: CB1 and CB2. Cannabinoids are neuroprotective against excitotoxicity and acute brain damage, both in vitro and in vivo. Several mechanisms account for the neuroprotection afforded by this type of drug such as blockade of excitotoxicity, reduction of calcium influx, antioxidant properties of the compounds, or enhanced trophic factor support. A decrease in proinflammatory mediators brought about by cannabinoids may be also involved in their neuroprotection… Cannabidiol (CBD), the major plant-derived nonpsychotropic constituent of marijuana, is of potential therapeutic interest in different disease conditions (e.g., inflammation)…

…this kind of drug with neuroprotective and anti-inflammatory effects may be of interest in the prevention of AD inflammation, in particular CB2-selective agonists, which are devoid of psychoactive effects…

Cannabidiol and other cannabinoids reduce microglial activation in vitro and in vivo…

CBD is able to modulate microglial cell function in vitro and induce beneficial effects in an in vivo model of AD.

Given that CBD lacks psychoactivity, it may represent a novel therapeutic approach for this neurological disease.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102548/

Cannabinoid CB1 receptor stimulation affords neuroprotection in MPTP-induced neurotoxicity by attenuating S100B up-regulation in vitro.

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 “…the involvement of the endocannabinoid system was investigated by using selective inhibitors of endocannabinoid inactivation (cellular re-uptake or enzymatic hydrolysis) and selective cannabinoid CB1 and CB2 receptor antagonists and by silencing the CB1 receptor…

 Our data suggest that selective activation of CB1 receptors by either exogenous or endogenous cannabinoids might afford neuroprotection…”

http://www.ncbi.nlm.nih.gov/pubmed/17639288

Contrasting protective effects of cannabinoids against oxidative stress and amyloid-β evoked neurotoxicity in vitro.

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“Cannabinoids have been widely reported to have neuroprotective properties in vitro and in vivo. In this study we compared the effects of CB1 and CB2 receptor-selective ligands, the endocannabinoid anandamide and the phytocannabinoid cannabidiol, against oxidative stress and the toxic hallmark Alzheimer’s protein, β-amyloid (Aβ)…

 …the endocannabinoid anandamide protects neuronal cells from Aβ exposure via a pathway unrelated to CB1 or CB2 receptor activation…protective effect of cannabidiol against oxidative stress…

…divergent pathways for neuroprotection of these two cannabinoids.”

http://www.ncbi.nlm.nih.gov/pubmed/22233683

Prevention of Alzheimer’s Disease Pathology by Cannabinoids: Neuroprotection Mediated by Blockade of Microglial Activation

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“Cannabinoids are neuroprotective agents against excitotoxicity in vitro and acute brain damage in vivo. This background prompted us to study the localization, expression, and function of cannabinoid receptors in AD and the possible protective role of cannabinoids after betaA treatment, both in vivo and in vitro. Here, we show that senile plaques in AD patients express cannabinoid receptors CB1 and CB2……

…Our results indicate that cannabinoid receptors are important in the pathology of AD and that cannabinoids succeed in preventing the neurodegenerative process occurring in the disease.”

Free full text: http://www.jneurosci.org/content/25/8/1904.long

Cannabinoid Treatments: Amyotrophic Lateral Sclerosis (ALS)

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“Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a fatal neurodegenerative disorder that is characterized by the selective loss of motor neurons in the spinal cord, brain stem, and motor cortex. An estimated 30,000 Americans are living with ALS, which often arises spontaneously and afflicts otherwise healthy adults. More than half of ALS patients die within 2.5 years following the onset of symptoms.

A review of the scientific literature reveals an absence of clinical trials investigating the use of cannabinoids for ALS treatment. However, recent preclinical findings indicate that cannabinoids can delay ALS progression, lending support to anecdotal reports by patients that cannabinoids may be efficacious in moderating the disease’s development and in alleviating certain ALS-related symptoms such as pain, appetite loss, depression and drooling.

Writing in the March 2004 issue of the journal Amyotrophic Lateral Sclerosis & Other Motor Neuron Disorders, investigators at the California Pacific Medical Center in San Francisco reported that the administration of THC both before and after the onset of ALS symptoms staved disease progression and prolonged survival in animals compared to untreated controls.

Additional trials in animal models of ALS have shown that the administration of other naturally occurring and synthetic cannabinoids can also moderate ALS progression but not necessarily impact survival. One recent study demonstrated that blocking the CB1 cannabinoid receptor did extend life span in an ALS mouse model, suggesting that cannabinoids’ beneficial effects on ALS may be mediated by non-CB1 receptor mechanisms.

As a result, experts are calling for clinical trials to assess cannabinoids for the treatment of ALS. Writing in the American Journal of Hospice & Palliative Medicine in 2010, a team of investigators reported, “Based on the currently available scientific data, it is reasonable to think that cannabis might significantly slow the progression of ALS, potentially extending life expectancy and substantially reducing the overall burden of the disease.” They concluded, “There is an overwhelming amount of preclinical and clinical evidence to warrant initiating a multicenter randomized, double-blind, placebo-controlled trial of cannabis as a disease-modifying compound in ALS.”

By braatahon December 25, 2012| From braatah.com