Endocannabinoid system

The endocannabinoid system (ECS) is a complex cell-signaling system identified in the early 1990s. It involves endogenous cannabinoids (endocannabinoids), receptors, and enzymes that synthesize and break down endocannabinoids. The ECS plays a vital role in regulating various physiological and cognitive processes, including fertility, pregnancy, pain, mood, and memory. It comprises cannabinoid receptors (CB1 and CB2), which are found throughout the body, especially in the central nervous system and immune system.

Components of the Endocannabinoid System

• The endocannabinoid system consists of endogenous arachidonate-based lipids such as anandamide and 2-AG.
• Enzymes like fatty acid amide hydrolase are responsible for synthesizing and degrading endocannabinoids.
• Cannabinoid receptors CB1 and CB2, which are G protein-coupled receptors, are crucial components in the nervous system.
• Neurons, pathways, and cells where these molecules are colocalized form the ECS.
• Cannabinoids serve as neuromodulators influencing processes like motor learning and appetite regulation.

Expression of Cannabinoid Receptors

• Cannabinoid binding sites are present in both the central and peripheral nervous systems.
• CB1 and CB2 receptors are predominantly expressed in the brain and immune system.
• The density of receptor expression varies by species, impacting the efficacy of behavior modulation.
• Rodents exhibit the highest concentration of cannabinoid binding sites in the basal ganglia and cerebellum.
• Human cannabinoid receptors are found in lower concentrations in these regions.

Role of the Endocannabinoid System in Physiological Processes

• The ECS plays a crucial role in regulating physiological and cognitive processes.
• It is involved in fertility, pregnancy, immune system function, appetite regulation, pain-sensation, mood, and memory.
• The ECS influences neural functions such as movement control, learning, emotion, and pain modulation.
• CB1 receptors are the primary molecular targets for anandamide and tetrahydrocannabinol.
• The endocannabinoid 2-AG acts as a full agonist at both CB receptors.

Research and Studies on the Endocannabinoid System

• The ECS is still undergoing preliminary research to understand its full functions.
• Studies have demonstrated that cannabinoids act as neuromodulators for various physiological processes.
• Localization of the CB1 receptor overlaps with functions mediated by the orexinergic projection system.
• Genetic and pharmacological methods have been utilized to study the ECS.
• The CB1 receptor is colocalized with orexin projection neurons in the lateral hypothalamus.

Terminology and Nomenclature of the Endocannabinoid System

• The ECS is also referred to as the endocannabinoidome or expanded endocannabinoid system.
• Endocannabinoids are eicosanoids and serve as physiological ligands for cannabinoid receptors.
• Enzymes like monoacylglycerol lipase are involved in the synthesis and degradation of endocannabinoids.
• CB1 and CB2 are the two primary cannabinoid receptors identified in the ECS.
• Components of the ECS include neurons, neural pathways, and cells where molecules are colocalized.

Endocannabinoid system Data Sources