What cannot be overstated is the importance of the discovery of the endocannabinoid system (ECS) for the human body.
Present in nearly all living animals, the system consists of the cannabinoid receptors CB1 and CB2, the endocannabinoid ligands anandamide (AEA) and 2-arachidonoylglycerol (2-AG), and their metabolic enzymes. Found throughout the brain, connective tissues, glands, immune cells, and organs, together they form a system of locks (cannabinoid receptors) and keys (endocannabinoids), which play a major role in day-to-day bodily functions and are responsible for homeostasis, or the maintenance of a stable internal environment, in the body. The ECS is recognized as probably the most important modulatory system in the human body.
However, the journey to the discovery of the ECS was only made possible by pioneering research into the cannabis sativa plant. According to Professor Raphael Mechoulam, known as “The Father Of Cannabis Research”:
“The work on the plant has now led to the identification of a major physiological system (the endocannabinoid system), which seems to be involved in many human diseases. The plant THC mimics compounds found in the brain, named endocannabinoids (anandamide and 2-AG), which we discovered in 1992 and 1995. These two endogenous brain cannabinoids are of immense importance in the working of our body.”
Researchers have discovered that modulating the activity of the ECS holds therapeutic promise for treating a wide range of diseases and pathological conditions and there are a growing number of studies exploring its regulatory functions in health and disease.
These studies have not only offered new insights into the mechanisms underlying the therapeutic actions of plant-derived phytocannabinoids like tetrahydrocannabinol (THC) and cannabidiol (CBD), but are also exploring novel molecular targets for pharmacotherapy as well.
Of course, because of its main role as a modulator of day-to-day physiological functions, one of the main areas of research in recent years has been the ECS’s participation in both the homeostatic and hedonic (pleasure) aspects of eating.
The ECS and eating disorders
The ECS has been well-documented to be involved in controlling and regulating eating behavior. To date, there have been numerous studies that have found the ECS to be a valuable pharmacotherapeutic target for obesity and other metabolic disorders.
But what about its potential role in treating eating disorders?
Eating disorders are mental disorders that are serious and often fatal illnesses that cause severe and abnormal eating habits.
According to the National Institute of Mental Health, obsessions with food, body weight, and shape may also signal an eating disorder. Common eating disorders include anorexia nervosa (where people eat very little food and have a low body weight), bulimia nervosa (where people eat a lot of food and then try to purge themselves of the food), and binge-eating disorder (where people eat a large amount of food in a short period of time). Anxiety disorders, depression, and substance abuse are common among people with eating disorders.
Adequate nutrition, reducing excessive exercise, and stopping purging behaviors are the foundations of treatment. Treatment plans are tailored to individual needs and may include medical care and monitoring, nutritional counseling, psychotherapies, and medications.
Unfortunately, although clinical studies indicate some improvement in the pharmacological management of eating disorders, treatment options are quite restricted and relapse incidences are still high. Limited progress in the development of strategies for the treatment of eating disorders is mainly due to the fact that the factors that cause these disorders are complex and not yet completely understood.
However, one of the more promising avenues for research has been the endocannabinoid system, which has long been known to be an important regulator of day-to-day physiological functions, including the homeostatic and hedonic aspects of eating.
To explore the role of the ECS in eating disorders, a team of Italian researchers reviewed the scientific literature and published their findings in 2014 in the journal Current Pharmaceutical Design.
The authors identified several reports that lead to the hypothesis that a dysregulation of neuronal pathways, which encode the rewarding value of food (i.e. limbic system), may drive individuals with eating disorders to aberrant eating behaviors. Furthermore, they found that therapeutic strategies based on drugs that modulate endocannabinoid system signaling might be useful in the treatment of these disorders.
In fact, they found that pharmacotherapy may be especially useful in some patients at risk of excessive weight gain and obesity due to a binge-eating disorder. For example, studies have shown that chronic pharmacological blockade of CB1 receptors reduces binge eating behavior in female rats and may prove effective in significantly reducing body weight. Although the CB1 receptor antagonist Rimonobant was banned from the European market for causing psychiatric side effects, the authors pointed out that research for the development of new antagonists of the CB1 receptor is still active, and that neutral or peripheral antagonists may be safer in terms of side effects, but may still retain metabolic actions. They suggested that given its ability to suppress caloric intake, CBD should be considered for the treatment of binge-eating disorders.
Another area of great interest is in utilizing pharmacotherapies for patients with anorexia who are chronically under voluntary food restriction that causes excessive weight loss.
Several studies in the past have demonstrated cannabis’ ability to stimulate the appetite and support weight gain for patients undergoing chemotherapy and for patients with HIV. The authors also found encouraging results on the rationality of a cannabinoid pharmacotherapy, demonstrating the effectiveness of THC in rescuing animals from the great body weight loss associated with the development of anorexia, thus improving the survival rate.
(However, it’s important to note that because of the psychoactive properties of THC, high doses of the drug cannot be easily tolerated. Thus, the inclusion of CBD which can counteract some of the intoxicating effects of THC may allow for higher doses and better beneficial effects.)
The researchers concluded that strenuous research on the identification of drugs acting on the endocannabinoid system but that also impinge on other associated neurotransmitter systems can lead to an important progress in the pharmacotherapy of eating disorders.
Next Article: How CB1 and CB2 Receptors Regulate Impulsive Behaviors