Monthly Archives: October 2012

Cannabidiol for neurodegenerative disorders: important new clinical applications for this phytocannabinoid?

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Abstract

“Cannabidiol (CBD) is a phytocannabinoid with therapeutic properties for numerous disorders exerted through molecular mechanisms that are yet to be completely identified. CBD acts in some experimental models as an anti-inflammatory, anticonvulsant, antioxidant, antiemetic, anxiolytic and antipsychotic agent, and is therefore a potential medicine for the treatment of neuroinflammation, epilepsy, oxidative injury, vomiting and nausea, anxiety and schizophrenia, respectively. The neuroprotective potential of CBD, based on the combination of its anti-inflammatory and antioxidant properties, is of particular interest and is presently under intense preclinical research in numerous neurodegenerative disorders. In fact, CBD combined with Δ(9) -tetrahydrocannabinol is already under clinical evaluation in patients with Huntington’s disease to determine its potential as a disease-modifying therapy. The neuroprotective properties of CBD do not appear to be exerted by the activation of key targets within the endocannabinoid system for plant-derived cannabinoids like Δ(9) -tetrahydrocannabinol, i.e. CB(1) and CB(2) receptors, as CBD has negligible activity at these cannabinoid receptors, although certain activity at the CB(2) receptor has been documented in specific pathological conditions (i.e. damage of immature brain). Within the endocannabinoid system, CBD has been shown to have an inhibitory effect on the inactivation of endocannabinoids (i.e. inhibition of FAAH enzyme), thereby enhancing the action of these endogenous molecules on cannabinoid receptors, which is also noted in certain pathological conditions. CBD acts not only through the endocannabinoid system, but also causes direct or indirect activation of metabotropic receptors for serotonin or adenosine, and can target nuclear receptors of the PPAR family and also ion channels.”

http://www.ncbi.nlm.nih.gov/pubmed/22625422

Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia

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“Cannabidiol is a component of marijuana that does not activate cannabinoid receptors, but moderately inhibits the degradation of the endocannabinoid anandamide. We previously reported that an elevation of anandamide levels in cerebrospinal fluid inversely correlated to psychotic symptoms. Furthermore, enhanced anandamide signaling let to a lower transition rate from initial prodromal states into frank psychosis as well as postponed transition. In our translational approach, we performed a double-blind, randomized clinical trial of cannabidiol vs amisulpride, a potent antipsychotic, in acute schizophrenia to evaluate the clinical relevance of our initial findings. Either treatment was safe and led to significant clinical improvement, but cannabidiol displayed a markedly superior side-effect profile. Moreover, cannabidiol treatment was accompanied by a significant increase in serum anandamide levels, which was significantly associated with clinical improvement. The results suggest that inhibition of anandamide deactivation may contribute to the antipsychotic effects of cannabidiol potentially representing a completely new mechanism in the treatment of schizophrenia.”

“Cannabidiol is a non-psychotropic component of marijuana that binds to CB1 receptors with only comparably very low affinity and is devoid of overt cannabimimetic or pro-psychotic properties. Biochemical studies indicate that cannabidiol may enhance endogenous anandamide signaling indirectly, by inhibiting the intracellular degradation of anandamide catalyzed by the enzyme fatty acid amide hydrolase (FAAH).Furthermore, preliminary clinical case reports suggest that cannabidiol might exert antipsychotic effects in schizophrenic patients. In addition, experimental studies show that cannabidiol reduces psychosis-like effects of Δ9-tetrahydrocannabinol and synthetic analogs.“

Read more:: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3316151/

Marijuana Compound Treats Schizophrenia with Few Side Effects:Clinical Trial

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“A compound found in marijuana can treat schizophrenia as effectively as antipsychotic medications, with far fewer side effects, according to a preliminary clinical trial.

“Because it comes from marijuana, there are obvious political issues surrounding its use. Extracting it from the plant is also expensive. But the biggest barrier may be that CBD is a natural compound, and therefore can’t be patented the way new drugs are. That means that despite the possibility that it could outsell their current blockbuster antipsychotic drugs, pharmaceutical companies aren’t likely to develop it — a particularly striking fact when you consider that every major manufacturer of new generation antipsychotics in the U.S. has so far paid out hundreds of millions or billions of dollars in fines for mismarketing these drugs. Yet they still reaped huge profits.”

“For people with schizophrenia and their families, of course, it is likely to be infuriating that non-scientific issues like marijuana policy and patenting problems could stand in the way of a treatment that could potentially be so restorative. While it’s possible that these study results may not hold up or that researchers could discover problems related to long-term use of CBD,  it’s hard to imagine that they could be any worse than what patients already experience.”

Read more: http://healthland.time.com/2012/05/30/marijuana-compound-treats-schizophrenia-with-few-side-effects-clinical-trial/

Medical use of cannabis. Cannabidiol: A new light for schizophrenia?

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Abstract

“The medical properties of cannabis have been known for many centuries; its first documented use dates back to 2800 BC when it was described for its hallucinogenic and pain-relieving properties. In the first half of the twentieth century, a number of pharmaceutical companies marked cannabis for indications such as asthma and pain, but since then its use has sharply declined, mainly due to its unpredictable effects, but also for socio-political issues. Recently, great attention has been directed to the medical properties of phytocannabinoids present in the cannabis plant alongside the main constituent Δ(9) -Tetrahydrocannabinol (THC); these include cannabinoids such as cannabidiol (CBD), cannabigerol (CBG), and tetrahydrocannabivarin (THCV). Evidence suggests an association between cannabis and schizophrenia: schizophrenics show a higher use of marijuana as compared to the healthy population. Additionally, the use of marijuana can trigger psychotic episodes in schizophrenic patients, and this has been ascribed to THC. Given the need to reduce the side effects of marketed antipsychotics, and their weak efficacy on some schizophrenic symptoms, cannabinoids have been suggested as a possible alternative treatment for schizophrenia. CBD, a non-psychoactive constituent of the Cannabis sativa plant, has been receiving growing attention for its anti-psychotic-like properties. Evidence suggests that CBD can ameliorate positive and negative symptoms of schizophrenia. Behavioural and neurochemical models suggest that CBD has a pharmacological profile similar to that of atypical anti-psychotic drugs and a clinical trial reported that this cannabinoid is a well-tolerated alternative treatment for schizophrenia.”

http://www.ncbi.nlm.nih.gov/pubmed/23109356

Multiple mechanisms involved in the large-spectrum therapeutic potential of cannabidiol in psychiatric disorders.

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Abstract

“Cannabidiol (CBD) is a major phytocannabinoid present in the Cannabis sativa plant. It lacks the psychotomimetic and other psychotropic effects that the main plant compound Δ(9)-tetrahydrocannabinol (THC) being able, on the contrary, to antagonize these effects. This property, together with its safety profile, was an initial stimulus for the investigation of CBD pharmacological properties. It is now clear that CBD has therapeutic potential over a wide range of non-psychiatric and psychiatric disorders such as anxiety, depression and psychosis. Although the pharmacological effects of CBD in different biological systems have been extensively investigated by in vitro studies, the mechanisms responsible for its therapeutic potential are still not clear. Here, we review recent in vivo studies indicating that these mechanisms are not unitary but rather depend on the behavioural response being measured. Acute anxiolytic and antidepressant-like effects seem to rely mainly on facilitation of 5-HT1A-mediated neurotransmission in key brain areas related to defensive responses, including the dorsal periaqueductal grey, bed nucleus of the stria terminalis and medial prefrontal cortex. Other effects, such as anti-compulsive, increased extinction and impaired reconsolidation of aversive memories, and facilitation of adult hippocampal neurogenesis could depend on potentiation of anandamide-mediated neurotransmission. Finally, activation of TRPV1 channels may help us to explain the antipsychotic effect and the bell-shaped dose-response curves commonly observed with CBD. Considering its safety profile and wide range of therapeutic potential, however, further studies are needed to investigate the involvement of other possible mechanisms (e.g. inhibition of adenosine uptake, inverse agonism at CB2 receptor, CB1 receptor antagonism, GPR55 antagonism, PPARγ receptors agonism, intracellular (Ca(2+)) increase, etc.), on CBD behavioural effects.”

http://www.ncbi.nlm.nih.gov/pubmed/23108553

Targeting the endocannabinoid system with cannabinoid receptor agonists: pharmacological strategies and therapeutic possibilities.

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Philosophical Transactions of the Royal Society B: Biological Sciences: 367 (1607)

“Human tissues express cannabinoid CB(1) and CB(2) receptors that can be activated by endogenously released ‘endocannabinoids’ or exogenously administered compounds in a manner that reduces the symptoms or opposes the underlying causes of several disorders in need of effective therapy. Three medicines that activate cannabinoid CB(1)/CB(2) receptors are now in the clinic: Cesamet (nabilone), Marinol (dronabinol; Δ(9)-tetrahydrocannabinol (Δ(9)-THC)) and Sativex (Δ(9)-THC with cannabidiol). These can be prescribed for the amelioration of chemotherapy-induced nausea and vomiting (Cesamet and Marinol), stimulation of appetite (Marinol) and symptomatic relief of cancer pain and/or management of neuropathic pain and spasticity in adults with multiple sclerosis (Sativex). This review mentions several possible additional therapeutic targets for cannabinoid receptor agonists. These include other kinds of pain, epilepsy, anxiety, depression, Parkinson’s and Huntington’s diseases, amyotrophic lateral sclerosis, stroke, cancer, drug dependence, glaucoma, autoimmune uveitis, osteoporosis, sepsis, and hepatic, renal, intestinal and cardiovascular disorders. It also describes potential strategies for improving the efficacy and/or benefit-to-risk ratio of these agonists in the clinic. These are strategies that involve (i) targeting cannabinoid receptors located outside the blood-brain barrier, (ii) targeting cannabinoid receptors expressed by a particular tissue, (iii) targeting upregulated cannabinoid receptors, (iv) selectively targeting cannabinoid CB(2) receptors, and/or (v) adjunctive ‘multi-targeting’.”  https://www.ncbi.nlm.nih.gov/pubmed/23108552

“Targeting the endocannabinoid system with cannabinoid receptor agonists: pharmacological strategies and therapeutic possibilities”  http://rstb.royalsocietypublishing.org/content/367/1607/3353.long

Endocannabinoids in nervous system health and disease: the big picture in a nutshell.

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Abstract

“The psychoactive component of the cannabis resin and flowers, delta9-tetrahydrocannabinol (THC), was first isolated in 1964, and at least 70 other structurally related ‘phytocannabinoid’ compounds have since been identified. The serendipitous identification of a G-protein-coupled cannabinoid receptor at which THC is active in the brain heralded an explosion in cannabinoid research. Elements of the endocannabinoid system (ECS) comprise the cannabinoid receptors, a family of nascent lipid ligands, the ‘endocannabinoids’ and the machinery for their biosynthesis and metabolism. The function of the ECS is thus defined by modulation of these receptors, in particular, by two of the best-described ligands, 2-arachidonoyl glycerol and anandamide (arachidonylethanolamide). Research on the ECS has recently aroused enormous interest not only for the physiological functions, but also for the promising therapeutic potentials of drugs interfering with the activity of cannabinoid receptors. Many of the former relate to stress-recovery systems and to the maintenance of homeostatic balance. Among other functions, the ECS is involved in neuroprotection, modulation of nociception, regulation of motor activity, neurogenesis, synaptic plasticity and the control of certain phases of memory processing. In addition, the ECS acts to modulate the immune and inflammatory responses and to maintain a positive energy balance. This theme issue aims to provide the reader with an overview of ECS pharmacology, followed by discussions on the pivotal role of this system in the modulation of neurogenesis in the developing and adult organism, memory processes and synaptic plasticity, as well as in pathological pain and brain ageing. The volume will conclude with discussions that address the proposed therapeutic applications of targeting the ECS for the treatment of neurodegeneration, pain and mental illness.”

http://www.ncbi.nlm.nih.gov/pubmed/23108539

Cannabinoids and innate immunity: taking a toll on neuroinflammation.

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Abstract

“The biologically active components of cannabis have therapeutic potential in neuroinflammatory disorders due to their anti-inflammatory propensity. Cannabinoids influence immune function in both the peripheral and the central nervous system (CNS), and the components of the cannabinoid system, the cannabinoid receptors and their endogenous ligands (endocannabinoids), have been detected on immune cells as well as in brain glia. Neuroinflammation is the complex innate immune response of neural tissue to control infection and eliminate pathogens, and Toll-like receptors (TLRs), a major family of pattern recognition receptors (PRRs) that mediate innate immunity, have emerged as players in the neuroinflammatory processes underpinning various CNS diseases. This review will highlight evidence that cannabinoids interact with the immune system by impacting TLR-mediated signaling events, which may provide cues for devising novel therapeutic approaches for cannabinoid ligands.”

http://www.ncbi.nlm.nih.gov/pubmed/21479354

Cannabinoid receptor signalling in neurodegenerative diseases: a potential role for membrane fluidity disturbance

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Abstract

“Type-1 cannabinoid receptor (CB1) is the most abundant G-protein-coupled receptor (GPCR) in the brain. CB1 and its endogenous agonists, the so-called ‘endocannabinoids (eCBs)’, belong to an ancient neurosignalling system that plays important functions in neurodegenerative and neuroinflammatory disorders like Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis and multiple sclerosis. For this reason, research on the therapeutic potential of drugs modulating the endogenous tone of eCBs is very intense. Several GPCRs reside within subdomains of the plasma membranes that contain high concentrations of cholesterol: the lipid rafts. Here, the hypothesis that changes in membrane fluidity alter function of the endocannabinoid system, as well as progression of particular neurodegenerative diseases, is described. To this end, the impact of membrane cholesterol on membrane properties and hence on neurodegenerative diseases, as well as on CB1 signalling in vitro and on CB1-dependent neurotransmission within the striatum, is discussed. Overall, present evidence points to the membrane environment as a critical regulator of signal transduction triggered by CB1, and calls for further studies aimed at better clarifying the contribution of membrane lipids to eCBs signalling. The results of these investigations might be exploited also for the development of novel therapeutics able to combat disorders associated with abnormal activity of CB1.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165948/

Role of CB1 cannabinoid receptors on GABAergic neurons in brain aging

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“Brain aging is associated with cognitive decline that is accompanied by progressive neuroinflammatory changes. The endocannabinoid system (ECS) is involved in the regulation of glial activity and influences the progression of age-related learning and memory deficits.

Mice lacking the Cnr1 gene (Cnr1−/−), which encodes the cannabinoid receptor 1 (CB1), showed an accelerated age-dependent deficit in spatial learning accompanied by a loss of principal neurons in the hippocampus. The age-dependent decrease in neuronal numbers in Cnr1−/− mice was not related to decreased neurogenesis or to epileptic seizures. However, enhanced neuroinflammation characterized by an increased density of astrocytes and activated microglia as well as an enhanced expression of the inflammatory cytokine IL-6 during aging was present in the hippocampus of Cnr1−/− mice. The ongoing process of pyramidal cell degeneration and neuroinflammation can exacerbate each other and both contribute to the cognitive deficits. Deletion of CB1 receptors from the forebrain GABAergic, but not from the glutamatergic neurons, led to a similar neuronal loss and increased neuroinflammation in the hippocampus as observed in animals lacking CB1 receptors in all cells.

Our results suggest that CB1 receptor activity on hippocampal GABAergic neurons protects against age-dependent cognitive decline by reducing pyramidal cell degeneration and neuroinflammation.”