Getting into the weed: the role of the endocannabinoid system in the brain-gut axis.

“The actions of cannabis are mediated by receptors that are part of an endogenous cannabinoid system.

The endocannabinoid system (ECS) consists of the naturally occurring ligands N-arachidonoylethanolamine (anandamide) and 2-arachidonoylglycerol (2-AG), their biosynthetic and degradative enzymes, and the cannabinoid receptors CB1 and CB2.

The ECS is a widely distributed transmitter system that controls gut functions peripherally and centrally. It is an important physiologic regulator of gastrointestinal motility.

Polymorphisms in the gene encoding CB1 (CNR1) have been associated with some forms of irritable bowel syndrome. The ECS is involved in the control of nausea and vomiting and visceral sensation. The homeostatic role of the ECS also extends to the control of intestinal inflammation.

We review the mechanisms by which the ECS links stress and visceral pain. CB1 in sensory ganglia controls visceral sensation, and transcription of CNR1 is modified through epigenetic processes under conditions of chronic stress. These processes might link stress with abdominal pain.

The ECS is also involved centrally in the manifestation of stress, and endocannabinoid signaling reduces the activity of hypothalamic-pituitary-adrenal pathways via actions in specific brain regions-notably the prefrontal cortex, amygdala, and hypothalamus.

Agents that modulate the ECS are in early stages of development for treatment of gastrointestinal diseases. Increasing our understanding of the ECS will greatly advance our knowledge of interactions between the brain and gut and could lead to new treatments for gastrointestinal disorders.”

http://www.ncbi.nlm.nih.gov/pubmed/27133395

ENDOCANNABINOID SYSTEM: A multi-facet therapeutic target.

Image result for Curr Clin Pharmacol.

“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

Medicinal cannabis.

“A number of therapeutic uses of cannabis and its derivatives have been postulated from preclinical investigations.

Possible clinical indications include spasticity and pain in multiple sclerosis, cancer-associated nausea and vomiting, cancer pain and HIV neuropathy.

Controversies lie in how to produce, supply and administer cannabinoid products.

Introduction of cannabinoids therapeutically should be supported by a regulatory and educational framework that minimises the risk of harm to patients and the community.

The Regulator of Medicinal Cannabis Bill 2014 is under consideration in Australia to address this.

Nabiximols is the only cannabinoid on the Australian Register of Therapeutic Goods at present, although cannabidiol has been recommended for inclusion in Schedule 4.”

http://www.ncbi.nlm.nih.gov/pubmed/26843715

“There is some evidence of therapeutic benefit for cannabis products in defined patient populations.” http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4674028/

Endocannabinoid Mechanisms Influencing Nausea.

“One of the first recognized medical uses of Δ(9)-tetrahydrocannabinol was treatment of chemotherapy-induced nausea and vomiting.

Although vomiting is well controlled with the currently available non-cannabinoid antiemetics, nausea continues to be a distressing side effect of chemotherapy and other disorders.

Indeed, when nausea becomes conditionally elicited by the cues associated with chemotherapy treatment, known as anticipatory nausea (AN), currently available antiemetics are largely ineffective.

Considerable evidence demonstrates that the endocannabinoid system regulates nausea in humans and other animals.

In this review, we describe recent evidence suggesting that cannabinoids and manipulations that enhance the functioning of the natural endocannabinoid system are promising treatments for both acute nausea and AN.”

Controlled release tablet formulation containing natural δ9 tetrahydrocannabinol.

“Cannabinoids are increasingly being used in the treatment of chemotherapy induced nausea and vomiting (CINV) because of their action on the cannabinoid receptors, CB1 and CB2.

The currently marketed capsule formulations (sesame oil based and crystalline powder) are required to be administered frequently to maintain therapeutic levels, which leads to non-compliance.

In the present study, oral controlled release tablet formulations of Δ9- tetrahydrocannabinol (THC) were prepared using the lipids Precirol® and Compritrol®. Release profiles using THC-lipid matrices and/or with the lipids in the external phase (blend) were evaluated…

The overall results demonstrate the feasibility of preparing oral THC tablets for once a day administration which can improve CINV management.”

http://www.ncbi.nlm.nih.gov/pubmed/26585693

Cannabinoids for nausea and vomiting in adults with cancer receiving chemotherapy.

“Cannabis has a long history of medicinal use.

Cannabis-based medications (cannabinoids) are based on its active element, delta-9-tetrahydrocannabinol (THC), and have been approved for medical purposes.

Cannabinoids may be a useful therapeutic option for people with chemotherapy-induced nausea and vomiting that respond poorly to commonly used anti-emetic agents (anti-sickness drugs).

Cannabis-based medications may be useful for treating refractory chemotherapy-induced nausea and vomiting.”

http://www.ncbi.nlm.nih.gov/pubmed/26561338

http://www.thctotalhealthcare.com/category/nauseavomiting/

Endocannabinoid regulation of nausea is mediated by 2-arachidonoylglycerol (2-AG) in the rat visceral insular cortex.

“Cannabinoid (CB) agonists suppress nausea in humans and animal models; yet, their underlying neural substrates remain largely unknown.

Evidence suggests that the visceral insular cortex (VIC) plays a critical role in nausea. Given the expression of CB1 receptors and the presence of endocannabinoids in this brain region, we hypothesized that the VIC endocannabinoid system regulates nausea…

Taken together, these findings provide compelling evidence that acute nausea selectively increases 2-AG in the VIC, and suggests that 2-AG signaling within the VIC regulates nausea by reducing neuronal activity in this forebrain region.”

A comparison of cannabidiolic acid with other treatments for anticipatory nausea using a rat model of contextually elicited conditioned gaping.

“The effectiveness of cannabidiolic acid (CBDA) was compared with other potential treatments for anticipatory nausea (AN), using a rat model of contextually elicited conditioned gaping reactions.

The potential of ondansetron (OND), Δ(9)-tetrahydrocannabinol (THC), chlordiazepoxide (CDP), CBDA, and co-administration of CBDA and tetrahydrocannabinolic acid (THCA) to reduce AN and modify locomotor activity was evaluated…

CBDA has therapeutic potential as a highly potent and selective treatment for AN without psychoactive or locomotor effects.”

http://www.ncbi.nlm.nih.gov/pubmed/24595502

Cannabidiolic acid prevents vomiting in Suncus murinus and nausea-induced behaviour in rats by enhancing 5-HT1A receptor activation.

“The cannabis plant is a natural source of at least 70 compounds known collectively as phytocannabinoids, and there is convincing evidence that one of these, cannabidiol (CBD), can suppress nausea and vomiting.

To evaluate the ability of cannabidiolic acid (CBDA) to reduce nausea and vomiting and enhance 5-HT(1A) receptor activation in animal models…

Compared with cannabidiol, CBDA displays significantly greater potency at inhibiting vomiting in shrews and nausea in rats, and at enhancing 5-HT(1A) receptor activation, an action that accounts for its ability to attenuate conditioned gaping in rats.

Consequently, CBDA shows promise as a treatment for nausea and vomiting, including anticipatory nausea for which no specific therapy is currently available.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3596650/

Neuromotor tolerability and behavioural characterisation of cannabidiolic acid, a phytocannabinoid with therapeutic potential for anticipatory nausea.

“Anticipatory nausea (AN) is a poorly controlled side effect experienced by chemotherapy patients. Currently, pharmacotherapy is restricted to benzodiazepine anxiolytics, which have limited efficacy, have significant sedative effects and induce dependency.

The non-psychoactive phytocannabinoid, cannabidiolic acid (CBDA), has shown considerable efficacy in pre-clinical AN models…:

This study aims to assess the tolerability of CBDA in locomotor activity, motor coordination and muscular strength tests, and additionally for ability to modulate feeding behaviours…

CBDA is very well tolerated and devoid of the sedative side effect profile of benzodiazepines, justifying its clinical investigation as a novel AN treatment.”

http://www.ncbi.nlm.nih.gov/pubmed/26439367