ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

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“Cannabis sativa is also popularly known as marijuana. It is being cultivated and used by man for recreational and medicinal purposes from many centuries.

Study of cannabinoids was at bay for very long time and its therapeutic value could not be adequately harnessed due to its legal status as proscribed drug in most of the countries.

The research of drugs acting on endocannabinoid system has seen many ups and down in recent past. Presently, it is known that endocannabinoids has role in pathology of many disorders and they also serve “protective role” in many medical conditions.

Several diseases like emesis, pain, inflammation, multiple sclerosis, anorexia, epilepsy, glaucoma, schizophrenia, cardiovascular disorders, cancer, obesity, metabolic syndrome related diseases, Parkinson’s disease, Huntington’s disease, Alzheimer’s disease and Tourette’s syndrome could possibly be treated by drugs modulating endocannabinoid system.

Presently, cannabinoid receptor agonists like nabilone and dronabinol are used for reducing the chemotherapy induced vomiting. Sativex (cannabidiol and THC combination) is approved in the UK, Spain and New Zealand to treat spasticity due to multiple sclerosis. In US it is under investigation for cancer pain, another drug Epidiolex (cannabidiol) is also under investigation in US for childhood seizures. Rimonabant, CB1 receptor antagonist appeared as a promising anti-obesity drug during clinical trials but it also exhibited remarkable psychiatric side effect profile. Due to which the US Food and Drug Administration did not approve Rimonabant in US. It sale was also suspended across the EU in 2008.

Recent discontinuation of clinical trial related to FAAH inhibitor due to occurrence of serious adverse events in the participating subjects could be discouraging for the research fraternity. Despite of some mishaps in clinical trials related to drugs acting on endocannabinoid system, still lot of research is being carried out to explore and establish the therapeutic targets for both cannabinoid receptor agonists and antagonists.

One challenge is to develop drugs that target only cannabinoid receptors in a particular tissue and another is to invent drugs that acts selectively on cannabinoid receptors located outside the blood brain barrier. Besides this, development of the suitable dosage forms with maximum efficacy and minimum adverse effects is also warranted.

Another angle to be introspected for therapeutic abilities of this group of drugs is non-CB1 and non-CB2 receptor targets for cannabinoids.

In order to successfully exploit the therapeutic potential of endocannabinoid system, it is imperative to further characterize the endocannabinoid system in terms of identification of the exact cellular location of cannabinoid receptors and their role as “protective” and “disease inducing substance”, time-dependent changes in the expression of cannabinoid receptors.”

http://www.ncbi.nlm.nih.gov/pubmed/27086601

Cannabidiol-2′,6′-dimethyl ether stimulates body weight gain in apolipoprotein E-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice.

“The biological activities of cannabidiol (CBD), a major non-psychotropic constituent of the fiber-type cannabis plant, have been examined in detail (e.g., CBD modulation of body weight in mice and rats).

However, few studies have investigated the biological activities of cannabidiol-2′,6′-dimethyl ether (CBDD), a dimethyl ether derivative of the parent CBD.

We herein focused on the effects of CBDD on body weight changes in mice, and demonstrated that it stimulated body weight gain in apolipoprotein E (ApoE)-deficient BALB/c. KOR/Stm Slc-Apoe(shl) mice, especially between 10 and 20 weeks of age.”

http://www.ncbi.nlm.nih.gov/pubmed/26558454

Endocannabinoids and Metabolic Disorders.

“The endocannabinoid system (ECS) is known to exert regulatory control on essentially every aspect related to the search for, and the intake, metabolism and storage of calories, and consequently it represents a potential pharmacotherapeutic target for obesity, diabetes and eating disorders.

While the clinical use of the first generation of cannabinoid type 1 (CB1) receptor blockers has been halted due to the psychiatric side effects that their use occasioned, recent research in animals and humans has provided new knowledge on the mechanisms of actions of the ECS in the regulation of eating behavior, energy balance, and metabolism.

In this review, we discuss these recent advances and how they may allow targeting the ECS in a more specific and selective manner for the future development of therapies against obesity, metabolic syndrome, and eating disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/26408168

Therapeutic potential of cannabis-related drugs.

“In this review, I will consider the dual nature of Cannabis and cannabinoids.

The duality arises from the potential and actuality of cannabinoids in the laboratory and clinic and the ‘abuse’ of Cannabis outside the clinic.

The therapeutic areas currently best associated with exploitation of Cannabis-related medicines include pain, epilepsy, feeding disorders, multiple sclerosis and glaucoma.

As with every other medicinal drug of course, the ‘trick’ will be to maximise the benefit and minimise the cost.

After millennia of proximity and exploitation of the Cannabis plant, we are still playing catch up with an understanding of its potential influence for medicinal benefit.”

http://www.ncbi.nlm.nih.gov/pubmed/26216862

Biomedical benefits of cannabinoids?

“Cannabinoids appear to be of therapeutic value as antiemetics, antispasmodics, analgesics and appetite stimulants and may have potential uses in epilepsy, glaucoma and asthma.

This paper reviews the clinical trials which have been carried out with cannabinoids including Δ⁹-tetrahydrocannabinol (THC) and synthetic cannabinoids such as nabilone and levonantradol, and discusses the advantages and adverse effects of cannabinoids in clinical use.

The place of cannabinoids in modern medicine remains to be properly evaluated, but present evidence suggests that they could be valuable, particularly as adjuvants, for symptom control in a range of conditions for which standard drugs are not fully satisfactory.”

Very low doses of delta 8-THC increase food consumption and alter neurotransmitter levels following weight loss.

“We have investigated the effect of 0.001 mg/kg delta(8)-tetrahydrocannabinol (THC) on food consumption, cognitive function, and neurotransmitters in mice…

Cognitive function showed a tendency to improve in the THC-treated mice…

Delta(8)-THC increased food intake significantly more than did delta(9)-THC, while performance and activity were similar.

Thus, delta(8)-THC (0.001 mg/kg) caused increased food consumption and tendency to improve cognitive function, without cannabimimetic side effects.

Hence, a low dose of THC might be a potential therapeutic agent in the treatment of weight disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/15099912

[Cannabinoids in medicine].

“Cannabinoids have been known for many centuries because of their various effects in healthcare. They are primarily effective in reducing nausea, vomiting, pain, anorexia, spasticity and depression. Some other effects are known, all seem to be mediated by cannabinoid receptors in the central nervous system. In the past years, medical use has been proven in several studies. Today, the therapeutical use of cannabinoids in medicine is increasing, and access was made easier. Especially in pain-management and palliative care, they seem to be a valuable therapeutic option.”

http://www.ncbi.nlm.nih.gov/pubmed/19165445

Negative Regulation of Leptin-induced ROS Formation by CB1 Receptor Activation in Hypothalamic Neurons.

“The adipocyte-derived, anorectic hormone, leptin, was recently shown to owe part of its regulatory effects on appetite-regulating hypothalamic neuropeptides to the elevation of ROS levels in arcuate nucleus (ARC) neurons.

Leptin is also known to exert a negative regulation on hypothalamic endocannabinoid levels and hence on cannabinoid CB1 receptor activity.

Here we investigated the possibility of a negative regulation by CB1 receptor of leptin-mediated ROS formation in the ARC…

We conclude that CB1 activation reverses leptin-induced ROS formation, and hence possibly some of the ROS-mediated effects of the hormone, by preventing PPAR-γ inhibition by leptin, with subsequent increase of catalase activity.

This mechanism might underlie in part CB1 orexigenic actions under physiopathological conditions accompanied by elevated hypothalamic endocannabinoid levels.”

Modulation of sweet taste sensitivities by endogenous leptin and endocannabinoids in mice.

“Leptin is an anorexigenic mediator that reduces food intake by acting on hypothalamic receptor, Ob-Rb. In contrast, endocannabinoids are orexigenic mediators that act via cannabinoid CB1 receptors in hypothalamus, limbic forebrain, and brainstem.

In the peripheral taste system, leptin administration selectively inhibits behavioral, taste nerve and taste cell responses to sweet compounds. Opposing the action of leptin, endocannabinoids enhance sweet taste responses.

Taken together, our results suggest that circulating leptin, but not local endocannabinoids, may be a dominant modulator for sweet taste in lean mice; however, endocannabinoids may become more effective modulators of sweet taste under conditions of deficient leptin signaling, possibly due to increased production of endocannabinoids in taste tissue.”

http://www.ncbi.nlm.nih.gov/pubmed/25728242

The role of cannabinoids in regulation of nausea and vomiting, and visceral pain.

“Marijuana derived from the plant Cannabis sativa has been used for the treatment of many gastrointestinal (GI) disorders, including anorexia, emesis, abdominal pain, diarrhea, and others.

Several cannabinoid receptors, which include the cannabinoid receptor 1 (CB1), CB2, and possibly GPR55, have been identified throughout the GI tract.

These receptors may play a role in the regulation of food intake, nausea and emesis, gastric secretion and gastroprotection, GI motility, ion transport, visceral sensation, intestinal inflammation, and cell proliferation in the gut.

…the regulation of nausea and vomiting by cannabinoids and the endocannabinoid system has shed new knowledge in this field.

Novel drug targets such as FAAH and monoacylglycerol lipase (MAGL) inhibitors appear to be promising in animal models, but more studies are necessary to prove their efficiency.

The promise of emerging drugs that are more selective and peripherally acting suggest that, in the near future, cannabinoids will play a major role in managing an array of GI diseases.”

http://www.ncbi.nlm.nih.gov/pubmed/25715910