The endocannabinoid system (ECS) was discovered in the 1990s. It is composed of several components:
- The CB1 and CB2 cannabinoid receptors, present in certain types of cells, which function as "locks";
- Cannabinoids that act as 'keys';
- Enzymes that serve to synthesise, transport or degrade endocannabinoids.
CB1 receptors
CB1 cannabinoid receptors are found throughout the body, but are massively expressed in the central nervous system (brain and spinal cord).
The functions of CB1 receptors
CB1 receptors regulate in particular :
- Metabolism
- Emotional responses.
They are also involved in processes that regulate thinking, memory and learning. Psychoactive substances such as THC readily bind to CB1 receptors.
CB2 receptors
CB2 cannabinoid receptors are concentrated in the peripheral nervous system - the nerves that connect the central nervous system to other areas of the body - and in certain types of immune cells.
The functions of CB2 receptors
CB2 receptors regulate certain body and muscle functions.
They also play a role in the immune system. Once activated, CB2 receptors reduce inflammation.
Cannabinoids that bind exclusively to CB2 receptors are generally not psychoactive.
Cannabinoids
A molecule is said to be cannabinoid when it binds and interacts with cannabinoid receptors. There are 2 types of cannabinoids:
- Exogenous or phytogenic cannabinoids come from outside the body.
There are several types of cannabinoids: THC, cannabidiol (CBD), CBN, CBG, etc. They are particularly abundant in cannabis, but many plants make them. They are particularly abundant in cannabis, but many plants make them.
- Endocannabinoids are produced naturally by the body.
To date, researchers have identified several. Anandamides play a key role in the regulation of mood and emotion. The main function of 2-AG is to reduce inflammation by regulating various immune system functions.
Why this name?
Originally, researchers wanted to understand how the active substances in cannabis (cannabinoids) interact with the human body. They therefore named the receptors involved 'cannabinoid receptors'.
Later, they discovered that the human body naturally produces molecules very similar to exogenous cannabinoids.
They too bind to and activate the same receptors. Scientists therefore named them endocannabinoids; the suffix 'endo-' meaning 'internal'.
The ESA therefore goes far beyond cannabis, but the original term has remained.
What is the purpose of the SEC?
In all likelihood, ECS is involved in the homeostasis of the body. It serves to maintain the balance of other systems: the nervous, immune, digestive, neuronal and hormonal systems, etc.
This undoubtedly explains the varied and multiple effects of certain cannabinoids on our health.
Having said that, research on the SEC has only just begun. Discovered barely thirty years ago, it is still far from having revealed all its secrets...
References
Devane, W.A. et al, "Determination and characterization of a cannabinoid receptor in rat brain", in Mol Pharm, 1988.
Munro S. et al, "Molecular characterization of a peripheral receptor for cannabinoids" in Nature, 1993.
Fezza, F. et al, "Endocannabinoids, related compounds and their metabolic routes" in Molecules, 2014.
Venance L. et al, "Endocannabinoids in the central nervous system" in Med Sci (Paris), 2004.
