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

[Marihuana and cannabinoids as medicaments].

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“Biological activity of cannabinoids is caused by binding to two cannabinoid receptors CB1 and CB2. Psychoactive is not only tetrahydrocannabinol (THC) but also: cannabidiol, cannabigerol or cannabichromen. Formerly, the usefulness of hemp was assessed in the relation to temporary appeasement of the symptoms of some ailments as nausea or vomiting.

 Present discoveries indicates that cannabis-based drugs has shown ability to alleviate of autoimmunological disorders such as: Multiple sclerosis (MS), Rheumatoid arthritis (RA) or inflammatory bowel disease. Another studies indicates that cannabinoids play role in treatment of neurological disorders like Alzheimer disease or Amyotrophic lateral sclerosis (ALS) or even can reduce spreading of tumor cells.

 Cannabinoids stand out high safety profile considering acute toxicity, it is low possibility of deadly overdosing and side-effects are comprise in range of tolerated side-effects of other medications.

In some countries marinol and nabilone are used as anti vomiting and nausea drug. First cannabis-based drug containg naturally occurring cannabinoids is Sativex. Sativex is delivered in an mucosal spray for patients suffering from spasticity in MS, pain relevant with cancer and neuropathic pain of various origin. Despite the relatively low acute toxicity of cannabinoids they should be avoid in patients with psychotic disorders, pregnant or breastfeeding woman. Cannabinoids prolong a time of reaction and decrease power of concentration that’s why driving any vehicles is forbidden.

 Cannabis side-effects varies and depend from several factors like administrated dose, rout of administration and present state of mind. After sudden break from long-lasting use, withdrawal symptoms can appear, although they entirely disappear after a week or two.”

http://www.ncbi.nlm.nih.gov/pubmed/23421098

Role of cannabinoid and vanilloid receptors in invasion of human breast carcinoma cells.

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“It is known that the diversified effects of cannabinoid on the fate of carcinoma cells are mediated predominantly through receptors. However, little is known about the effects of the individual activities of cannabinoid and noncannabinoid receptors. Here we investigate the role of cannabinoid receptor (CB) 1, CB2, and transient receptor potential vanilloid type 1 in cell proliferation and invasion patterns in the MDA-MB-231 cell line.

Our results showed that activation of CB1 and vanilloid receptors by methanandamide, a nonselective agonist, and arachidonyl-2′-choloroethylamide (ACEA) and N-oleoyldopamine, selective agonists, reduced invasion of MDA-MB-231 cells at pharmacological concentrations. Accordingly, CB1 activation resulted in decreased expression of matrix metalloproteinase (MMP) 2. On the other hand, administration of a CB2 agonist (CB65) increased cell invasion and expression of MMP2. The data obtained from MTT assay did not show any correlation between reduced invasion and cytotoxic effects of drugs. In addition, the level of vascular endothelial growth factor was significantly reduced in treatment with (R)-(+)-methanandamide, ACEA, CB65, and AM251 (a potent agonist for GPR55 and selective antagonist of CB1) compared with control. Elevated expression of cyclooxygenase-2 was observed in all of the MDA-MB-231 cells treated with agonists.

These results underline the influence of cannabinoid and vanilloid receptors on the invasiveness of MDA-MB-231 human breast carcinoma cells.”

http://www.ncbi.nlm.nih.gov/pubmed/23394450

The pharmacologic and clinical effects of medical cannabis.

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“Cannabis, or marijuana, has been used for medicinal purposes for many years. Several types of cannabinoid medicines are available in the United States and Canada. Dronabinol (schedule III), nabilone (schedule II), and nabiximols (not U.S. Food and Drug Administration approved) are cannabis-derived pharmaceuticals.

Medical cannabis or medical marijuana, a leafy plant cultivated for the production of its leaves and flowering tops, is a schedule I drug, but patients obtain it through cannabis dispensaries and statewide programs. The effect that cannabinoid compounds have on the cannabinoid receptors (CB(1) and CB(2) ) found in the brain can create varying pharmacologic responses based on formulation and patient characteristics. The cannabinoid Δ(9) -tetrahydrocannabinol has been determined to have the primary psychoactive effects; the effects of several other key cannabinoid compounds have yet to be fully elucidated. Dronabinol and nabilone are indicated for the treatment of nausea and vomiting associated with cancer chemotherapy and of anorexia associated with weight loss in patients with acquired immune deficiency syndrome. However, pain and muscle spasms are the most common reasons that medical cannabis is being recommended.

Studies of medical cannabis show significant improvement in various types of pain and muscle spasticity. Reported adverse effects are typically not serious, with the most common being dizziness. Safety concerns regarding cannabis include the increased risk of developing schizophrenia with adolescent use, impairments in memory and cognition, accidental pediatric ingestions, and lack of safety packaging for medical cannabis formulations. This article will describe the pharmacology of cannabis, effects of various dosage formulations, therapeutics benefits and risks of cannabis for pain and muscle spasm, and safety concerns of medical cannabis use.”

http://www.ncbi.nlm.nih.gov/pubmed/23386598

Inhibition of endocannabinoid degradation in experimental endotoxemia reduces leukocyte adhesion and improves capillary perfusion in the gut.

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“Changes in leukocyte-endothelial and microvascular perfusion are hallmark events in inflammation. Thus, protection of the intestinal microcirculation represents a pivotal therapeutic target in systemic inflammation and sepsis.

The endocannabinoid system (ECS) modulates a number of critical homeostatic functions and has been associated with anti-inflammatory responses. Our study aimed to examine intestinal leukocyte adhesion and capillary perfusion following selective inhibition of the endocannabinoid degradation enzyme, fatty acid amide hydrolase (FAAH), in experimental sepsis (endotoxemia).

Conclusions: FAAH inhibition prevents the LPS-induced increase in leukocyte adhesion and improves the capillary perfusion of the gut. This might be mediated in part by CB2R activation.

Our study encourages further investigation into the therapeutic potential of drugs targeting the ECS in sepsis.”

More: http://www.ncbi.nlm.nih.gov/pubmed/23382309

Update on the Role of Cannabinoid Receptors after Ischemic Stroke

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“The endocannabinoid system is considered as a major modulator of the cerebral blood flow, neuroinflammation, and neuronal survival… Evidence from animal models and in vitro studies suggests a global protective role for cannabinoid receptors agonists in ischemic stroke…Given its potent anti-inflammatory activities on circulating leukocytes, the CB2 activation has been proven to produce protective effects against acute poststroke inflammation. In this paper, we will update evidence on different cannabinoid-triggered avenues to reduce inflammation and neuronal injury in acute ischemic stroke…

Synthetic cannabinoids have been also investigated in animal models showing an improvement of the ischemic injury in the liver, heart, and brain. Furthermore, phytocannabinoids have been also isolated from the Cannabis sativa. Since this plant contains about 80 different cannabinoids, a strong work is still needed to test all these active compounds. This delay in cannabinoid research might be also due to the very low dose of certain cannabinoids in the plant. Thus, since Δ9-tetrahydrocannabidiol (THC) and cannabidiol (CBD) represent up to 40% of the total cannabinoid mass, these compounds have been considered as the most active mediators…

The encouraging therapeutic results of this study are in partial contrast with previous case reports, suggesting a potential relationship between stroke and chronic cannabis abuse in young human beings…

We believe that the “cannabinoid” approach represents an interesting therapeutic strategy still requiring further validations to improve neurologic and inflammatory outcomes in ischemic stroke.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337695/

Modulation of The Balance Between Cannabinoid CB1 and CB2 Receptor Activation During Cerebral Ischemic/Reperfusion Injury

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“A number of investigations have shown that CB2 receptor activation has anti-inflammatory therapeutic potential in various CNS diseases, such as multiple sclerosis, traumatic brain injury and Alzheimer’s disease. Because inflammatory responses have been shown to be important contributors to secondary injury following cerebral ischemia; the CB2 receptor has been investigated as a potential therapeutic target in stroke…

The most striking changes were obtained by combing a CB1 antagonist with a CB2 agonist. This combination elevated the cerebral blood flow during ischemia and reduced infarction by 75%…during cerebral ischemia/reperfusion injury, inhibition of CB1 receptor activation is protective while inhibition of CB2 receptor activation is detrimental.

 The greatest degree of neuroprotection was obtained by combining an inhibitor of CB1 activation with an exogenous CB2 agonist.

In conclusion, the results of this investigation demonstrate dynamic changes in the expression of CB1 and CB2 receptors during cerebral ischemic/reperfusion injury in mice. The effects of stimulation of these receptors on damage ischemia/reperfusion injury differed dramatically. Stimulation of the CB2 receptor was found to be neuroprotective, while inhibition of the CB1 receptor was also protective,too. The combination of a CB2 agonist and a CB1 antagonist provided the greatest degree of protection and indicated a synergistic effect derived from combining these agents. Therefore, changing the balance of stimulation of these receptors by endogenous cannabinoids may provide an important therapeutic strategy during stroke.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2577828/

Role of cannabinoids and endocannabinoids in cerebral ischemia

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“The human costs of stroke are very large and growing; it is the third largest cause of death in the United States and survivors are often faced with loss of ability to function independently. There is a large need for therapeutic approaches that act to protect neurons from the injury produced by ischemia and reperfusion… 

 Overall, the available data suggest that inhibition of CB1 receptor activation together with increased CB2 receptor activation produces beneficial effects.

These studies support the hypothesis that activation of the CB1 receptor by highly efficacious, exogenous agonists during the acute phase of ischemia decreases the likelihood of the occurrence of a detrimental event at the time of ischemia and thereby reduces the amount of infarction and neuronal death long-term… A protective role of the CB1 receptor is also supported by studies…

While it is possible that the ECS will be added to the long list of neuroprotective agents that show promise in animals and do not work in humans, there are a few reasons to be optimistic about this class of drugs. First, many of the other agents did not work because they do not cross the blood brain barrier. While the considerable lipophilicity of the cannabinoids poses its own set of problems, these drugs have no problems entering the brain. Second, the ECS is multifactorial and could “cover” multiple biochemical pathways in a single drug. Third, manipulations of the ECS has been shown to be beneficial in several preclinical models. Only time and further research will answer the most important question, are the cannabinoids of therapeutic benefit in humans suffering from stroke?”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2581413/

 

Endocannabinoid regulation of matrix metalloproteinases: implications in ischemic stroke.

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“Stroke is a major cause of morbidity and mortality and follows heart disease and cancer as the third leading cause of death in Western societies. Despite many advances in stroke research and pharmacotherapy, clinical treatment of this debilitating disorder is still inadequate.

Recent findings from several laboratories have identified the endocannabinoid signaling pathway, comprised of the endocannabinoid agonist anandamide and its pharmacological targets, CB1 and CB2 cannabinoid receptors and associated anandamide receptors, as a physiological system with capacity to mitigate cardiovascular and cerebrovascular disorders through neuronal and endothelial actions. Variability in experimental stroke models and modes of outcome evaluation, however, have provoked controversy regarding the precise roles of endocannabinoid signals in mediating neural and/or vascular protection versus neurovascular damage.

Clinical trials of the CB1 antagonist rimonabant demonstrate that modulation of endocannabinoid signaling during metabolic regulation of vascular disorders can significantly impact clinical outcomes, thus providing strong argument for therapeutic utility of endocannabinoids and/or cannabinoid receptors as targets for therapeutic intervention in cases of stroke and associated vascular disorders.

The purpose of this review is to provide updated information from basic science and clinical perspectives on endocannabinoid ligands and their effects in the pathophysiologic genesis of stroke. Particular emphasis will be placed on the endocannabinoids anandamide and 2-arachidonylglycerol and CB1 receptor-mediated mechanisms in the neurovascular unit during stroke pathogenesis. Deficiencies in our knowledge of endocannabinoids in the etiology and pathogenesis of stroke, caveats and limitations of existing studies, and future directions for investigation will be addressed.”

http://www.ncbi.nlm.nih.gov/pubmed/17979695

Endocannabinoids and cannabinoid receptors in ischaemia–reperfusion injury and preconditioning

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“This review is aimed to discuss the role of endocannabinoids and CB receptors in various forms of I/R injury (myocardial, cerebral, hepatic and circulatory shock) and preconditioning, and to delineate the evidence supporting the therapeutic utility of selective CB2 receptor agonists, which are devoid of psychoactive effects, as a promising new approach to limit I/R-induced tissue damage.

In this review, we will discuss the triggers and sources of endocannabinoid production during various forms of I/R injury (myocardial, cerebral, hepatic and retinal ischaemia, and circulatory shock) and preconditioning, as well as the diverse role of these novel mediators and their receptors in these processes. We will also overview the accumulating evidence obtained through the use of various synthetic CB1/CB2 receptor ligands, with particular focus on the novel role of CB2 receptors, suggesting that the modulation of the endocannabinoid system can be therapeutically exploited in various forms of I/R injury.

Cerebral I/R (stroke)

The first evidence for the neuroprotective effect of CBs came from the stroke research field from studies using synthetic non-psychotropic CB Dexanabinol/HU-211, which exerted its beneficial effects through CB1/CB2-independent mechanisms.

Collectively, it appears that both CB1 agonists and antagonists may afford neuroprotective effects against cerebral I/R…

There is considerable interest in the development of selective CB2 receptor agonists, which are devoid of psychoactive properties of CB1 agonists, for various inflammatory disorders. Further studies should also establish the therapeutic window of protection during the reperfusion phase with the currently available CB2 receptor agonists, and new compounds should also be designed with better in vivo bioavailability, to devise clinically relevant treatment strategies against various forms of I/R. Nevertheless, the recently observed beneficial effects of CB2 receptor agonists in hepatic and other forms of I/R, coupled with the absence of psychoactive properties, and antifibrotic effects of CB2 receptor in the liver suggest that this approach may represent a novel promising strategy against various forms of I/R injury and other inflammatory disorders.”

Full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219536/

Cannabinoid receptors as novel targets for the treatment of melanoma

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“Melanoma causes the greatest number of skin cancer-related deaths worldwide. Here, we evaluated the efficacy of cannabinoid receptor agonists, a new family of potential antitumoral compounds, at skin melanoma. Human melanomas and melanoma cell lines express CB1 and CB2 cannabinoid receptors. Activation of these receptors decreased growth, proliferation, angiogenesis and metastasis, and increased apoptosis, of melanomas in mice. Cannabinoid antimelanoma activity was independent of the immune status of the animal, could be achieved without overt psychoactive effects and was selective for melanoma cells vs. normal melanocytes.

Cannabinoid antiproliferative action on melanoma cells…

 These findings may contribute to the design of new chemotherapeutic strategies for the management of melanoma.

 …the present report, together with the implication of CB2 receptors in the control of processes such as pain initiation, emesis, and inflammation, opens the attractive possibility of finding cannabinoid-based therapeutic strategies devoid of nondesired psychotropic side effects.

Specifically, the antiproliferative effect of cannabinoids reported here may set the basis for a new therapeutic approach for the treatment of malignant melanoma.”

Full text: http://www.fasebj.org/content/20/14/2633.long