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

Role of cannabinoid receptors and RAGE in inflammatory bowel disease.

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“The endocannabinoid system is involved in many inflammatory diseases, such as Crohn’s disease (CD) and ulcerative colitis (UC). The distribution and expression of cannabinoid receptors 1 (CNR1) and 2 (CNR2) in combination with inflammatory cytokines and RAGE (receptor of advanced glycation end products), which is also overactive in these diseases, in dependency of the extent of inflammation and alteration of the colon barrier is still unclear and needs to be elucidated…

 

CONCLUSION:

We showed that cannabinoid receptors are expressed differentially in inflammatory bowel disease and that the expression seems to be influenced by the underlying disease and by localized inflammation.”

http://www.ncbi.nlm.nih.gov/pubmed/21472688

Cannabinoids for gastrointestinal diseases: potential therapeutic applications.

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“Delta(9)-Tetrahydrocannabinol (the active ingredient of marijuana), as well as endogenous and synthetic cannabinoids, exert many biological functions by activating two types of cannabinoid receptors, CB(1) and CB(2) receptors. CB(1) receptors have been detected on enteric nerves, and pharmacological effects of their activation include gastroprotection, reduction of gastric and intestinal motility and reduction of intestinal secretion.

 The digestive tract also contains endogenous cannabinoids (i.e., the endocannabinoids anandamide and 2-aracidonylglycerol) and mechanisms for endocannabinoid inactivation (i.e., endocannabinoids uptake and enzymatic degradation). Cannabinoid receptors, endocannabinoids and the proteins involved in endocannabinoids inactivation are collectively referred as the ‘endogenous cannabinoid system’.

 A pharmacological modulation of the endogenous cannabinoid system could provide new therapeutics for the treatment of a number of gastrointestinal diseases, including nausea and vomiting, gastric ulcers, irritable bowel syndrome, Crohn’s disease, secretory diarrhoea, paralytic ileus and gastroesophageal reflux disease. Some cannabinoids are already in use clinically, for example, nabilone and delta(9)-tetrahydrocannabinol are used as antiemetics.”

http://www.ncbi.nlm.nih.gov/pubmed/12517253

Endocannabinoids and the gastrointestinal tract.

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“In the past centuries, different preparations of marijuana have been used for the treatment of gastrointestinal (GI) disorders, such as GI pain, gastroenteritis and diarrhea.

 Delta9-tetrahydrocannabinol (THC; the active component of marijuana), as well as endogenous and synthetic cannabinoids, exert their biological functions on the gastrointestinal tract by activating two types of cannabinoid receptors, cannabinoid type 1 receptor (CB1 receptor) and cannabinoid type 2 receptor (CB2 receptor). While CB1 receptors are located in the enteric nervous system and in sensory terminals of vagal and spinal neurons and regulate neurotransmitter release, CB2 receptors are mostly distributed in the immune system, with a role presently still difficult to establish.

Under pathophysiological conditions, the endocannabinoid system conveys protection to the GI tract, eg from inflammation and abnormally high gastric and enteric secretion.

 For such protective activities, the endocannabinoid system may represent a new promising therapeutic target against different GI disorders, including frankly inflammatory bowel diseases (eg, Crohn’s disease), functional bowel diseases (eg, irritable bowel syndrome), and secretion- and motility-related disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/16751708

The endocannabinoid system in the physiology and pathophysiology of the gastrointestinal tract.

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“Numerous investigations have recently demonstrated the important roles of the endocannabinoid system in the gastrointestinal (GI) tract under physiological and pathophysiological conditions.

 In the GI tract, cannabinoid type 1 (CB1) receptors are present in neurons of the enteric nervous system and in sensory terminals of vagal and spinal neurons, while cannabinoid type 2 receptors are located in immune cells. Activation of CB1 receptors was shown to modulate several functions in the GI tract, including gastric secretion, gastric emptying and intestinal motility.

Under pathophysiological conditions induced experimentally in rodents, the endocannabinoid system conveys protection to the GI tract (e.g. from inflammation and abnormally high gastric and enteric secretions).

Such protective activities are largely in agreement with anecdotal reports from folk medicine on the use of Cannabis sativa extracts by subjects suffering from various GI disorders.

 Thus, the endocannabinoid system may serve as a potentially promising therapeutic target against different GI disorders, including frankly inflammatory bowel diseases (e.g. Crohn’s disease), functional bowel diseases (e.g. irritable bowel syndrome) and secretion- and motility-related disorders.

As stimulation of this modulatory system by CB1 receptor agonists can lead to unwanted psychotropic side effects, an alternative and promising avenue for therapeutic applications resides in the treatment with CB1 receptor agonists that are unable to cross the blood-brain barrier, or with compounds that inhibit the degradation of endogenous ligands (endocannabinoids) of CB1 receptors, hence prolonging the activity of the endocannabinoid system.”

http://www.ncbi.nlm.nih.gov/pubmed/16133420

Evaluation of anti-invasion effect of cannabinoids on human hepatocarcinoma cells.

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“Cancer is a disease characterized by abnormal growth of cells. One of the most common types of liver cancers is called hepatocellular carcinoma (HCC) which is highly metastatic. As most of cannabinoids have shown anticancer effect against different cell lines in a number of reports, a biological investigation of two cannabinoids, CB65 (CB2 receptor agonist) and ACEA (CB1 receptor agonist) was carried out in this study.

In an attempt to find natural products as a new solution of cancer, this study was designed to investigate the potential antitumoral and anti-invasive activity of cannabinoids…

The results revealed that both cannabinoids reduce cell viability, cell invasion as well as MMP-2 and MMP-9 expression in higher dose of 20 nM. Furthermore, higher concentrations of examined cannabinoids were more effective.

These data suggest ACEA and CB65 as an option for novel treatment of hepatocellular cancer.

Our findings may contribute to design of new therapeutic strategies for the management of HCC.”

http://www.ncbi.nlm.nih.gov/pubmed/22978792

Overexpression of cannabinoid receptors CB1 and CB2 correlates with improved prognosis of patients with hepatocellular carcinoma.

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“CB1 and CB2 are multifunctional cannabinoid-specific receptors considered to be involved in inhibition of tumor development…

To elucidate their roles in hepatocarcinogenesis, we analyzed the expression of these receptors in tumor and matched nontumorous tissues of human hepatocellular carcinoma (HCC) samples.

Our results indicate that CB1 and CB2 have potential as prognostic indicators and suggest possible beneficial effects of cannabinoids on prognosis of patients with HCC.”

http://www.ncbi.nlm.nih.gov/pubmed/17074588

Anti-proliferative effects of anandamide in human hepatocellular carcinoma cells.

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“In our previous study, we reported that the cannabinoid receptors CB1 and CB2 are overexpressed in human hepatocellular carcinoma (HCC) tissues. Recently, the antitumor potential of the endogenous cannabinoid anandamide (AEA) has also been addressed. The present study was conducted to investigate the anti-proliferative effects of AEA in HCC cells…

The results of this study demonstrated that AEA inhibited the proliferation of Huh7 cells, resulted in G1 cell cycle arrest and induced apoptosis…

This study defines the anti-proliferative effects of anandamide in HCC cells and suggests that AEA has therapeutic potential in the management of HCC patients.”

http://www.ncbi.nlm.nih.gov/pubmed/22970038

Cannabinoid Receptor 2-Mediated Attenuation of CXCR4-Tropic HIV Infection in Primary CD4+ T Cells

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“Agents that activate cannabinoid receptor pathways have been tested as treatments for cachexia, nausea or neuropathic pain in HIV-1/AIDS patients… Cannabinoid agonists activate the CB1R and CB2R cannabinoid receptors…

Cannabinoid agonists are currently under investigation for the treatment of AIDS-associated cachexia, nausea, and neuropathic pain. One such drug, dronabinol (Δ9-THC; Marinol®), has won Food and Drug Administration (FDA) approval for treatment of HIV-associated anorexia. Additionally, the prescription of smoked or ingested cannabis (marijuana) for treatment of AIDS-related symptoms has been approved…. Despite the use of cannabinoids by HIV/AIDS patients, few studies have investigated the impact of such drugs in regard to viral pathogenesis or immune regulation…

….Indeed, both smoked marijuana and dronabinol were reported to increase total CD4+ T cell number and naïve T cell number over a 21-day period. A decrease in viral load was also observed in these patients. Similarly, in SIV infected rhesus macaques, Δ9-THC exposure reduced viral load and CD4+ T cell depletion, significantly increasing animal survival over an 11 month period.

. Our findings suggest that CB2R activation in CD4+ T cells can inhibit actin reorganization and impair productive infection following cell-free or cell-associated viral acquisition of CXCR4-tropic HIV-1 in resting cells.

Therefore, the clinical use of CB2R agonists in the treatment of AIDS symptoms may also exert beneficial adjunctive antiviral effects against CXCR4-tropic viruses in late stages of HIV-1 infection.

Further study of cannabinoids and other neuroendocrine regulators that selectively modulate immune function may result in the discovery of new anti-viral drugs that can also mitigate AIDS-associated symptoms.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3309010/

Proof of Concept Trial of Dronabinol in Obstructive Sleep Apnea

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“… Δ9-TetraHydroCannabinol (Δ9THC) stabilizes autonomic output during sleep, reduces spontaneous sleep-disordered breathing, and blocks serotonin-induced exacerbation of sleep apnea. On this basis, we examined the safety, tolerability, and efficacy of dronabinol (Δ9THC), an exogenous Cannabinoid type 1 and type 2 (CB1 and CB2) receptor agonist in patients with Obstructive Sleep Apnea (OSA)…

Conclusion: Dronabinol treatment is safe and well-tolerated in OSA patients at doses of 2.5–10mg daily and significantly reduces AHI in the short-term. These findings should be confirmed in a larger study in order to identify sub-populations with OSA that may benefit from cannabimimetic pharmacologic therapy…

This proof of concept study demonstrates that dronabinol is safe, well-tolerated, and reduces AHI by approximately a third over 3 weeks of oral administration. Dronabinol treatment may be a viable alternative or adjunctive therapy in selected patients with OSA.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3550518/

Cannabinoids ameliorate impairments induced by chronic stress to synaptic plasticity and short-term memory.

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“Repeated stress is one of the environmental factors that precipitates and exacerbates mental illnesses like depression and anxiety as well as cognitive impairments. We have previously shown that cannabinoids can prevent the effects of acute stress on learning and memory.

Here we aimed to find whether chronic cannabinoid treatment would alleviate the long-term effects of exposure to chronic restraint stress on memory and plasticity as well as on behavioral and neuroendocrine measures of anxiety and depression. Late adolescence rats were exposed to chronic restraint stress for two weeks followed each day by systemic treatment with vehicle or with the CB1/2 receptor agonist WIN55,212-2 (1.2 mg/kg). Thirty days after the last exposure to stress, rats demonstrated impaired long-term potentiation (LTP) in the ventral subiculum (vSub)-nucleus accumbens (NAc) pathway, impaired performance in the prefrontal cortex (PFC)-dependent object recognition task and the hippocampal-dependent spatial version of this task, increased anxiety levels, and significantly reduced expression of glucocorticoid receptors (GRs) in the amygdala, hippocampus, PFC and NAc. Chronic WIN55,212-2 administration prevented the stress-induced impairment in LTP levels and in the spatial task, with no effect on stress-induced alterations in unconditioned anxiety levels or GR levels. The CB1 antagonist AM251 (0.3 mg/kg) prevented the ameliorating effects of WIN55,212-2 on LTP and short-term memory. Hence, the beneficial effects of WIN55,212-2 on memory and plasticity are mediated by CB1 receptors and are not mediated by alterations in GR levels in the brain areas tested.

 Our findings suggest that cannabinoid receptor activation could represent a novel approach to the treatment of cognitive deficits that accompany a variety of stress-related neuropsychiatric disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/23426383