What is the endocannabinoid system?
The endocannabinoid system (ECS) is composed of a vast network of chemical signals and cellular neuroreceptors, densely present in our brain and body.
Cannabinoid receptors in the brain, known as CB1 receptors, are more numerous than any other type of brain receptor. They act as regulators, controlling the levels and activity of most neurotransmitters. Through immediate feedback, these receptors increase or decrease the activity of bodily systems requiring adjustment, be it hunger, temperature or alertness.
To activate these receptors, our bodies produce molecules called endocannabinoids, which share a structure similar to that of the molecules in the cannabis plant. The first endocannabinoid discovered was named anandamide, after the Sanskrit word “ananda” meaning happiness.
This means that we all have tiny cannabis-like molecules floating around in our brains. The cannabis plant, used by humans for around 5,000 years, essentially works by “hijacking” this ancient cellular machinery.
A second type of cannabinoid receptor, the CB2 receptor, is found mainly in our immune tissues. It plays a crucial role in controlling our immune function, modulating inflammation, intestinal contraction and pain in inflammatory bowel conditions.
CB2 receptors are particularly interesting for drug development because, unlike CB1 receptors, their stimulation does not cause the “high” associated with cannabis, making them a more attractive target for medical treatments without the undesirable side effects.
What role does the endocannabinoid system play in learning and memory?
We know that the endocannabinoid system plays a crucial role in learning and memory, and several lines of research confirm this.
One obvious observation is that one of the main side effects of high doses of recreational cannabis is the temporary disruption of short-term memory, which returns to normal with abstinence. Sophisticated studies have also been carried out into how humans respond to the administration of THC (the active ingredient in cannabis), examining both their capacity for short-term memory and the patterns observed via functional brain imaging.
According to Michael Pollan, in his best-selling book The Botany of Desire, cannabis is one of the plants with which humans have co-evolved for thousands of years. Pollan suggests that forgetting plays an essential role in our brain’s ability to function without being overloaded by the countless sensory inputs that continually bombard us. Without this ability to forget, we would be overwhelmed, and cannabis could help us manage this overload.
The role of the endocannabinoid system in forgetting also opens up prospects for the treatment of post-traumatic stress disorder (PTSD), a condition where intrusive and unpleasant memories haunt people, causing a set of disruptive symptoms linked to pathological recollection.
What role does ECS play in hunger and the fine-tuning of weight-loss drugs?
The story of the drug rimonabant, which blocks the CB1 receptor, is a revealing example of the central role of the endocannabinoid system (ECS) in many crucial functions.
Developed as an anti-obesity drug, the idea behind rimonabant was that the endocannabinoid system controls hunger. This was based on evidence, including the fact that cannabis causes “the munchies”. By blocking the CB1 receptor, this was expected to lead to weight loss, and rimonabant did indeed succeed in making people lose weight.
However, the endocannabinoid system also regulates mood, and the drug had to be withdrawn from the market in a hurry because people taking it were becoming suicidal. This shows just how complex and interconnected the ECS is in the body.
In the future, with a better understanding of the subtleties of the SEC, it may be possible to develop a weight-loss drug that specifically targets cannabinoid receptors linked to weight loss, without affecting those that regulate mood.
Exploring the endocannabinoid system could lead to the discovery of new drugs
Originally, the study of the endocannabinoid system focused on efforts to understand (and often demonize) an illegal substance. However, recent research has evolved into a much broader exploration of what is an incredibly complex and extensive system, through which our bodies manage learning, sensation, motivation and overall balance.
We are truly at the dawn of an era of discovery of the endocannabinoid system and the development of new drugs that could help alleviate some of the cruelest diseases suffered by humans (and animals).
Glossary of the Endocannabinoid System :
- Endocannabinoid system (ECS): intercellular communication system responsible for balancing metabolic processes and optimizing body functions.
- Phytocannabinoid: Cannabinoid produced naturally by a plant.
- Endocannabinoid: Cannabinoid produced naturally by the human or animal body.
- Synthetic cannabinoids : Cannabinoids created in the laboratory.
- Cannabinoid receptor: Components of the endocannabinoid system responsible for activation and binding to endocannabinoids/phytocannabinoids.
- Cannabinoid enzymes: components of the endocrine system that synthesize and break down cannabinoids.
- Homeostasis: All the functions that ensure the stability and equilibrium of our organism in the face of change, with the aim of maintaining relative constancy in the composition and properties of an organism.
Many of us are familiar with our body’s regulatory systems, such as the sympathetic nervous system, responsible for our fight-or-flight response. However, the more recently discovered endocannabinoid system (ECS) remains less well known, despite its essential role in almost every aspect of our daily functioning.
The SEC plays a central role in regulating and controlling many critical bodily functions, including learning and memory, emotional processing, sleep, body temperature regulation, pain management, as well as inflammatory and immune responses, not to mention appetite. Currently, the SEC is the focus of intense international research and represents a promising avenue for the development of new drugs.
