WHAT IS THE ENDOCANABINOID SYSTEM?
The endocannabinoid system is a biological system present not only in the human body but also in other animals, which was discovered during the 80s and 90s and about which there is still a lot of ignorance today. It is known that it is a fundamental homeostatic regulator in the human body and that it plays a role in almost all physiological systems in our body1. The endocannabinoid system is mainly composed of:
- Endocannabinoids: which are the molecules that will bind to the receptors of cannabinoids and activate them (called retrograde neurotransmitters). They are present in cell membranes and are synthesized only in the necessary amounts. The main endocannabinoids are anandamide and 2-arachidonoylglycerol or 2-AG.
- Cannabinoid receptors: which are a type of proteins that are present on the surface of cells. These receptors monitor the conditions outside the cells and whenever they change (loss of homeostasis), they send signals inside them so that an adequate cellular response is given. The two main cannabinoid receptors are CB1, which are mostly present in the central nervous system, particularly in the brain, and CB2, which are more abundant outside the nervous system, mostly in the immune system.
- Metabolic enzymes: it is through these enzymes that endocannabinoids are used only when needed, breaking them down into other components after use. The main enzymes are FAAH (Fatty Acid Amide Hydrolase, or amide hydrolase of fatty acids), which break down anandamide, and MAGL (Monoacylglycerol Lipase), which break down 2-AG.2
It is through this triad that the endocannabinoid system helps to regulate a wide variety of functions, such as learning and memory, emotions and mood, sleep, appetite and metabolism, addiction behaviors, pain and neuroprotection3,4. Basically, the endocannabinoid system comes into play whenever something appears that alters the normal conditions of a cell. Through the action of endocannabinoids (produced only when needed), cannabinoid receptors (to which endocannabinoids bind to send the necessary signal into the cell) and metabolic enzymes (which break down endocannabinoids after use), it is possible to maintain homeostasis.
- Viveros M, by Fonseca F, Bermudez-Silva F, McPartland J. Critical role of the endocannabinoid system in the regulation of food intake and energy metabolism, with phylogenetic, developmental, and pathophysiological implications. Endocrine, Metabolic & Immune Disorders-Drug Targets 2008; 8 (3): 220-30.
- Silva S, et al. Endocannabinoid System - Therapeutic Intervention: Solution or Illusion? Portuguese Journal of Diabetes. 2009; 4 (3): 120-125.