Category Archives: Parkinson’s Disease

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

Cannabinoid receptor stimulation is anti-inflammatory and improves memory in old rats

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“The number of activated microglia increase during normal aging. Stimulation of endocannabinoid receptors can reduce the number of activated microglia, particularly in the hippocampus, of young rats infused chronically with lipopolysaccharide (LPS). In the current study we demonstrate that endocannabinoid receptor stimulation by administration of WIN-55212-2 (2 mg/kg/day) can reduce the number of activated microglia in hippocampus of aged rats and attenuate the spatial memory impairment in the water pool task. Our results suggest that the action of WIN-55212-2 does not depend upon a direct effect upon microglia or astrocytes but is dependent upon stimulation of neuronal cannabinoid receptors. Aging significantly reduced cannabinoid type 1 receptor binding but had no effect on cannabinoid receptor protein levels. Stimulation of cannabinoid receptors may provide clinical benefits in age-related diseases that are associated with brain inflammation, such as Alzheimer’s disease.”

“Our results are consistent with the hypothesis that CB receptors on hippocampal neurons modulate glutamatergic and GABAergic function and this leads to reduced microglia activation. This mechanism may underlie the neuroprotective effects of cannabinoids”.

“Importantly, the benefits of cannabinoid receptor stimulation occurred at a dose that did not impair performance in a spatial memory task, indeed the performance of aged rats was significantly improved. This finding is particularly relevant for elderly for patients suffering with diseases associated with brain inflammation, e.g. AD, Parkinson’s disease or multiple sclerosis. The current report is the first to our knowledge to demonstrate the anti-inflammatory actions of cannabinoid therapy in aged animals and strongly advocate an cannabinoid-based therapy for neuroinflammation-related diseases, as well as a potential tool to reduce the impairment in memory processes occurring during normal aging.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2586121/

Cannabinoid receptors and endocannabinoids: role in neuroinflammatory and neurodegenerative disorders.

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Abstract

“The G-protein coupled receptors for Δ⁹-tetrahydrocannabinol, the major psychoactive principle of marijuana, are known as cannabinoid receptors of type 1 (CB₁) and 2 (CB₂) and play important functions in degenerative and inflammatory disorders of the central nervous system. Whilst CB₁ receptors are mostly expressed in neurons, where they regulate neurotransmitter release and synaptic strength, CB₂ receptors are found mostly in glial cells and microglia, which become activated and over-express these receptors during disorders such as Alzheimer’s disease, multiple sclerosis, amyotropic lateral sclerosis, Parkinson’s disease, and Huntington’s chorea. The neuromodulatory actions at CB₁ receptors by endogenous agonists (‘endocannabinoids’), of which anandamide and 2-arachidonoylglycerol are the two most studied representatives, allows them to counteract the neurochemical unbalances arising during these disorders. In contrast, the immunomodulatory effects of these lipophilic mediators at CB₂ receptors regulate the activity and function of glia and microglia. Indeed, the level of expression of CB₁ and CB₂ receptors or of enzymes controlling endocannabinoid levels, and hence the concentrations of endocannabinoids, undergo time- and brain region-specific changes during neurodegenerative and neuroinflammatory disorders, with the initial attempt to counteract excitotoxicity and inflammation. Here we discuss this plasticity of the endocannabinoid system during the aforementioned central nervous system disorders, as well as its dysregulation, both of which have opened the way to the use of either direct and indirect activators or blockers of CB₁ and CB₂ receptors for the treatment of the symptoms or progression of these diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/20632970

Therapeutic aspects of cannabis and cannabinoids

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The British Journal of Psychiatry

“HISTORY OF THERAPEUTIC USE

The first formal report of cannabis as a medicine appeared in China nearly 5000 years ago when it was recommended for malaria, constipation, rheumatic pains and childbirth and, mixed with wine, as a surgical analgesic. There are subsequent records of its use throughout Asia, the Middle East, Southern Africa and South America. Accounts by Pliny, Dioscorides and Galen remained influential in European medicine for 16 centuries.”

“It was not until the 19th century that cannabis became a mainstream medicine in Britain. W. B. O’Shaughnessy, an Irish scientist and physician, observed its use in India as an analgesic, anticonvulsant, anti-spasmodic, anti-emetic and hypnotic. After toxicity experiments on goats and dogs, he gave it to patients and was impressed with its muscle-relaxant, anticonvulsant and analgesic properties, and recorded its use-fulness as an anti-emetic.”

“After these observations were published in 1842, medicinal use of cannabis expanded rapidly. It soon became available ‘over the counter’ in pharmacies and by 1854 it had found its way into the United States Dispensatory. The American market became flooded with dozens of cannabis-containing home remedies.”

“Cannabis was outlawed in 1928 by ratification of the 1925 Geneva Convention on the manufacture, sale and movement of dangerous drugs. Prescription remained possible until final prohibition under the 1971 Misuse of Drugs Act, against the advice of the Advisory Committee on Drug Dependence.”

“In the USA, medical use was effectively ruled out by the Marijuana Tax Act 1937. This ruling has been under almost constant legal challenge and many special dispensations were made between 1976 and 1992 for individuals to receive ‘compassionate reefers’. Although this loophole has been closed, a 1996 California state law permits cultivation or consumption of cannabis for medical purposes, if a doctor provides a written endorsement. Similar arrangements apply in Italy and Canberra, Australia.”

“Results and Conclusions Cannabis and some cannabinoids are effective anti-emetics and analgesics and reduce intra-ocular pressure. There is evidence of symptom relief and improved well-being in selected neurological conditions, AIDS and certain cancers. Cannabinoids may reduce anxiety and improve sleep. Anticonvulsant activity requires clarification. Other properties identified by basic research await evaluation. Standard treatments for many relevant disorders are unsatisfactory. Cannabis is safe in overdose but often produces unwanted effects, typically sedation, intoxication, clumsiness, dizziness, dry mouth, lowered blood pressure or increased heart rate. The discovery of specific receptors and natural ligands may lead to drug developments. Research is needed to optimise dose and route of administration, quantify therapeutic and adverse effects, and examine interactions.”

http://bjp.rcpsych.org/content/178/2/107.long

[The mechanism of action of cannabis and cannabinoids].

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Abstract

“The effect of cannabis can be explained on the basis of the function of the cannabinoid receptor system, which consists of CB receptors (CB1, CB2), endoligands to activate these receptors and an enzyme–fatty acid amidohydrolase–to metabolize the endoligands. The endoligands of the cannabinoid receptor system are arachidonic acid-like substances, and are called endocannabinoids. Indications exist that the body also contains arachidonic acid-like substances that inhibit fatty acid amido hydrolase. Various cannabinoids have diverse effects on the receptors, functioning as agonists, antagonists or partial antagonists, as well as affecting the vanilloid receptor. Many known effects of cannabis can be explained on the basis of this mechanism of action as can the use of cannabis in various conditions including multiple sclerosis, Parkinson’s disease, glaucoma, nausea, vomiting and rheumatoid arthritis.”

http://www.ncbi.nlm.nih.gov/pubmed/16463612

The therapeutic potential of novel cannabinoid receptors.

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Cover image

“Cannabinoids produce a plethora of biological effects, including the modulation of neuronal activity through the activation of CB(1) receptors and of immune responses through the activation of CB(2) receptors. The selective targeting of either of these two receptor subtypes has clear therapeutic value. Recent evidence indicates that some of the cannabinomimetic effects previously thought to be produced through CB(1) and/or CB(2) receptors, be they on neuronal activity, on the vasculature tone or immune responses, still persist despite the pharmacological blockade or genetic ablation of CB(1) and/or CB(2) receptors. This suggests that additional cannabinoid and cannabinoid-like receptors exist. Here we will review this evidence in the context of their therapeutic value and discuss their true belonging to the endocannabinoid signaling system.”  http://www.ncbi.nlm.nih.gov/pubmed/19248809

“The therapeutic potential of novel cannabinoid receptors”  http://www.sciencedirect.com/science/article/pii/S0163725809000266

[The role of the endocannabinoid system in the regulation of endocrine function and in the control of energy balance in humans].

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Abstract

“The endocannabinoid system has been recently recognized as an important modulatory system in the function of brain, endocrine, and immune tissues. It appears to play a very important regulatory role in the secretion of hormones related to reproductive functions and response to stress. The important elements of this system are: endocannabinoid receptors (types CB1 and CB2), their endogenous ligands (N-arachidonoylethanolamide, 2-arachidonoyl glycerol), enzymes involved in their synthesis and degradation, as well as cannabinoid antagonists. In humans this system also controls energy homeostasis and mainly influences the function of the food intake centers of the central nervous system and gastrointestinal tract activity. The endocannabinoid system regulates not only the central and peripheral mechanisms of food intake, but also lipids synthesis and turnover in the liver and adipose tissue as well as glucose metabolism in muscle cells. Rimonabant, a new and selective central and peripheral cannabinoid-1 receptor (CB1) blocker, has been shown to reduce body weight and improve cardiovascular risk factor (metabolic syndrome) in obese patients by increasing HDL-cholesterol and adiponectin blood levels as well as decreasing LDL-cholesterol, leptin, and C-reactive protein (a proinflammatory marker) concentrations. It is therefore possible to speculate about a future clinical use of CB1 antagonists, as a means of improving gonadotrophin pulsatility and fertilization capacity as well as the prevention of cardiovasculary disease and type 2 diabetes mellitus. Drugs acting as agonists of CB1 receptors (Dronabinol, Dexanabinol) are currently proposed for evaluation as drugs to treat neurodegenerative disorders (Alzheimer’s and Parkinson’s diseases), epilepsy, anxiety, and stroke.”

http://www.ncbi.nlm.nih.gov/pubmed/17369778

The Endocannabinoid System as an Emerging Target of Pharmacotherapy

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Abstract

“The recent identification of cannabinoid receptors and their endogenous lipid ligands has triggered an exponential growth of studies exploring the endocannabinoid system and its regulatory functions in health and disease. Such studies have been greatly facilitated by the introduction of selective cannabinoid receptor antagonists and inhibitors of endocannabinoid metabolism and transport, as well as mice deficient in cannabinoid receptors or the endocannabinoid-degrading enzyme fatty acid amidohydrolase. In the past decade, the endocannabinoid system has been implicated in a growing number of physiological functions, both in the central and peripheral nervous systems and in peripheral organs. More importantly, modulating the activity of the endocannabinoid system turned out to hold therapeutic promise in a wide range of disparate diseases and pathological conditions, ranging from mood and anxiety disorders, movement disorders such as Parkinson’s and Huntington’s disease, neuropathic pain, multiple sclerosis and spinal cord injury, to cancer, atherosclerosis, myocardial infarction, stroke, hypertension, glaucoma, obesity/metabolic syndrome, and osteoporosis, to name just a few. An impediment to the development of cannabinoid medications has been the socially unacceptable psychoactive properties of plant-derived or synthetic agonists, mediated by CB(1) receptors. However, this problem does not arise when the therapeutic aim is achieved by treatment with a CB(1) receptor antagonist, such as in obesity, and may also be absent when the action of endocannabinoids is enhanced indirectly through blocking their metabolism or transport. The use of selective CB(2) receptor agonists, which lack psychoactive properties, could represent another promising avenue for certain conditions. The abuse potential of plant-derived cannabinoids may also be limited through the use of preparations with controlled composition and the careful selection of dose and route of administration. The growing number of preclinical studies and clinical trials with compounds that modulate the endocannabinoid system will probably result in novel therapeutic approaches in a number of diseases for which current treatments do not fully address the patients’ need. Here, we provide a comprehensive overview on the current state of knowledge of the endocannabinoid system as a target of pharmacotherapy.”

Future Directions

“The length of this review, necessitated by the steady growth in the number of indications for the potential therapeutic use of cannabinoid-related medications, is a clear sign of the emerging importance of this field. This is further underlined by the quantity of articles in the public database dealing with the biology of cannabinoids, which numbered ∼200 to 300/year throughout the 1970s to reach an astonishing 5900 in 2004. The growing interest in the underlying science has been matched by a growth in the number of cannabinoid drugs in pharmaceutical development from two in 1995 to 27 in 2004, with the most actively pursued therapeutic targets being pain, obesity, and multiple sclerosis (Hensen, 2005). As in any rapidly growing area of research, not all the leads will turn out to be useful or even valid. Nevertheless, it is safe to predict that new therapeutic agents that affect the activity of the endocannaboinoid system will emerge and become members of our therapeutic armamentarium. The plant-derived cannabinoid preparation Sativex has already gained regulatory approval in Canada for the treatment of spasticity and pain associated with multiple sclerosis, and the CB1 receptor antagonist rimonabant has been approved in Europe and is awaiting Food and Drug Administration approval in the United States for the treatment of the metabolic syndrome. Undoubtedly, these will be followed by new and improved compounds aimed at the same or additional targets in the endocannabinoid system. However, it may be only after the widespread therapeutic use of such compounds that some important side effects will emerge. Although this occurrence would be undesirable from a health care perspective, such side effects may shed further light on the biological functions of endocannabinoids in health and disease.”

http://pharmrev.aspetjournals.org/content/58/3/389.long

The Endocannabinoid System and the Brain.

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Abstract

“The psychoactive constituent in cannabis, Δ(9)-tetrahydrocannabinol (THC), was isolated in the mid-1960s, but the cannabinoid receptors, CB1 and CB2, and the major endogenous cannabinoids (anandamide and 2-arachidonoyl glycerol) were identified only 20 to 25 years later. The cannabinoid system affects both central nervous system (CNS) and peripheral processes. In this review, we have tried to summarize research-with an emphasis on recent publications-on the actions of the endocannabinoid system on anxiety, depression, neurogenesis, reward, cognition, learning, and memory. The effects are at times biphasic-lower doses causing effects opposite to those seen at high doses. Recently, numerous endocannabinoid-like compounds have been identified in the brain. Only a few have been investigated for their CNS activity, and future investigations on their action may throw light on a wide spectrum of brain functions. Expected final online publication date for the Annual Review of Psychology Volume 64 is November 30, 2012. Please see http://www.annualreviews.org/catalog/pubdates.aspx for revised estimates.”

http://www.ncbi.nlm.nih.gov/pubmed/22804774

Unraveling the complexities of cannabinoid receptor 2 (CB2) immune regulation in health and disease

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CB2 is a potent regulator of immune responses making it a prime target for the treatment of inflammatory diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/21626285