Mechanisms of Broad-Spectrum Antiemetic Efficacy of Cannabinoids against Chemotherapy-Induced Acute and Delayed Vomiting.

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“Chemotherapy-induced nausea and vomiting (CINV) is a complex pathophysiological condition and consists of two phases.

The conventional CINV neurotransmitter hypothesis suggests that the immediate phase is mainly due to release of serotonin (5-HT) from the enterochromaffin cells in the gastrointestinal tract (GIT), while the delayed phase is a consequence of release of substance P (SP) in the brainstem. However, more recent findings argue against this simplistic neurotransmitter and anatomical view of CINV.

Revision of the hypothesis advocates a more complex, differential and overlapping involvement of several emetic neurotransmitters/modulators (e.g. dopamine, serotonin, substance P, prostaglandins and related arachidonic acid derived metabolites) in both phases of emesis occurring concomitantly in the brainstem and in the GIT enteric nervous system (ENS).

No single antiemetic is currently available to completely prevent both phases of CINV.

The standard antiemetic regimens include a 5-HT₃ antagonist plus dexamethasone for the prevention of acute emetic phase, combined with an NK1 receptor antagonist (e.g. aprepitant) for the delayed phase. Although NK1 antagonists behave in animals as broad-spectrum antiemetics against different emetogens including cisplatin-induced acute and delayed vomiting, by themselves they are not very effective against CINV in cancer patients.

Cannabinoids such as D⁸-THC also behave as broad-spectrum antiemetics against diverse emetic stimuli as well as being effective against both phases of CINV in animals and patients.

Potential side effects may limit the clinical utility of direct-acting cannabinoid agonists which could be avoided by the use of corresponding indirect-acting agonists.

Cannabinoids (both phyto-derived and synthetic) behave as agonist antiemetics via the activation of cannabinoid CB₁ receptors in both the brainstem and the ENS emetic loci.

An endocannabinoid antiemetic tone may exist since inverse CB₁ agonists (but not the corresponding silent antagonists) cause nausea and vomiting.”

https://www.ncbi.nlm.nih.gov/pubmed/27713384

Cannabinoids As Potential Treatment for Chemotherapy-Induced Nausea and Vomiting.

“Despite the advent of classic anti-emetics, chemotherapy-induced nausea is still problematic, with vomiting being somewhat better managed in the clinic.

If post-treatment nausea and vomiting are not properly controlled, anticipatory nausea-a conditioned response to the contextual cues associated with illness-inducing chemotherapy-can develop. Once it develops, anticipatory nausea is refractive to current anti-emetics, highlighting the need for alternative treatment options.

One of the first documented medicinal uses of Δ(9)-tetrahydrocannabinol (Δ(9)-THC) was for the treatment of chemotherapy-induced nausea and vomiting (CINV), and recent evidence is accumulating to suggest a role for the endocannabinoid system in modulating CINV.

Here, we review studies assessing the therapeutic potential of cannabinoids and manipulations of the endocannabinoid system in human patients and pre-clinical animal models of nausea and vomiting.”

http://www.ncbi.nlm.nih.gov/pubmed/27507945

Cannabinoids biology: the search for new therapeutic targets.

“Cannabinoids, in the form of marijuana plant extracts, have been used for thousands of years for a wide variety of medical conditions, ranging from general malaise and mood disorders to more specific ailments, such as pain, nausea, and muscle spasms.

The discovery of tetrahydrocannabinol, the active principal in marijuana, and the identification and cloning of two cannabinoid receptors (i.e., CB1 and CB2) has subsequently led to biomedical appreciation for a family of endocannabinoid lipid transmitters.

The biosynthesis and catabolism of the endocannabinoids and growing knowledge of their broad physiological roles are providing insight into potentially novel therapeutic targets.

Compounds directed at one or more of these targets may allow for cannabinoid-based therapeutics with limited side effects and abuse liability.”

http://www.ncbi.nlm.nih.gov/pubmed/16809476

Effect of combined oral doses of Δ9-tetrahydrocannabinol (THC) and cannabidiolic acid (CBDA) on acute and anticipatory nausea in rat models.

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“The purpose of this study was to evaluate the potential of oral combined cannabis constituents to reduce nausea.

The objective of this study was to determine the effect of combining subthreshold oral doses of Δ9-tetrahydrocannabinol (THC) and cannabidiolic acid (CBDA) on acute and anticipatory nausea in rat models of conditioned gaping.

RESULTS:

For acute nausea, i.g. administration of subthreshold doses of THC (0.5 and 1 mg/kg) or CBDA (0.5 and 1 μg/kg) significantly suppressed acute nausea-induced gaping, whereas higher individual doses of both THC and CBDA were maximally effective. Combined i.g. administration of higher doses of THC and CBDA (2.5 mg/kg THC-2.5 μg/kg CBDA; 10 mg/kg THC-10 μg/kg CBDA; 20 mg/kg THC-20 μg/kg CBDA) also enhanced positive hedonic reactions elicited by saccharin solution during conditioning. For anticipatory nausea, combined subthreshold i.g. doses of THC (0.1 mg/kg) and CBDA (0.1 μg/kg) suppressed contextually elicited conditioned gaping. When administered i.g., THC was effective on its own at doses ranging from 1 to 10 mg/kg, but CBDA was only effective at 10 μg/kg. THC alone was equally effective by intraperitoneal (i.p.) and i.g. administration, whereas CBDA alone was more effective by i.p. administration (Rock et al. in Psychopharmacol (Berl) 232:4445-4454, 2015) than by i.g. administration.

CONCLUSIONS:

Oral administration of subthreshold doses of THC and CBDA may be an effective new treatment for acute nausea and anticipatory nausea and appetite enhancement in chemotherapy patients.”

http://www.ncbi.nlm.nih.gov/pubmed/27438607

Dronabinol for chemotherapy-induced nausea and vomiting unresponsive to antiemetics.

“Chemotherapy-induced nausea and vomiting (CINV) is one of the most common symptoms feared by patients, but may be prevented or lessened with appropriate medications.

Several antiemetic options exist to manage CINV. Corticosteroids, serotonin receptor antagonists, and neurokinin receptor antagonists are the classes most commonly used in the prevention of CINV. There are many alternative drug classes utilized for the prevention and management of CINV such as antihistamines, benzodiazepines, anticonvulsants, cannabinoids, and dopamine receptor antagonists.

Medications belonging to these classes generally have lower efficacy and are associated with more adverse effects. They are also not as well studied compared to the aforementioned agents.

This review will focus on dronabinol, a member of the cannabinoid class, and its role in CINV.

Cannabis sativa L. (also known as marijuana) contains naturally occurring delta-9-tetrahydrocannibinol (delta-9-THC). The synthetic version of delta-9-THC is the active ingredient in dronabinol that makes dronabinol an orally active cannabinoid.

Evidence for clinical efficacy of dronabinol will be analyzed in this review as monotherapy, in combination with ondansetron, and in combination with prochlorperazine.”

http://www.ncbi.nlm.nih.gov/pubmed/27274310

Cannabinoid 2 (CB2) receptor agonism reduces lithium chloride-induced vomiting in Suncus murinus and nausea-induced conditioned gaping in rats.

“We aimed to investigate the potential anti-emetic and anti-nausea properties of targeting the cannabinoid 2 (CB2) receptor.

We investigated the effect of the selective CB2 agonist, HU-308, on lithium chloride- (LiCl) induced vomiting in Suncus murinus (S. murnius) and conditioned gaping (nausea-induced behaviour) in rats.

These findings are the first to demonstrate the ability of a selective CB2 receptor agonist to reduce nausea in animal models, indicating that targeting the CB2 receptor may be an effective strategy, devoid of psychoactive effects, for managing toxin-induced nausea and vomiting.”

http://www.ncbi.nlm.nih.gov/pubmed/27263826

Effects of Delta-9-Tetrahydrocannabinol and Cannabidiol on Cisplatin-Induced Neuropathy in Mice.

“Sativex, a cannabinoid extract with a 1 : 1 ratio of tetrahydocannabinol and cannabidiol, has been shown to alleviate neuropathic pain associated with chemotherapy.

This research examined whether tetrahydocannabinol or cannabidiol alone could attenuate or prevent cisplatin-induced tactile allodynia.

These data demonstrate that each of the major constituents of Sativex alone can achieve analgesic effects against cisplatin neuropathy.”

http://www.ncbi.nlm.nih.gov/pubmed/27214593

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/