What is the Endocannabinoid System?

Scientific research has discovered many things over the years about the human body. There are many more things to be explored and the endocannabinoid system is one of them. Every year, we learn more about this complex biological system that controls physical and psychological functions in the body. And there’s certainly a great deal more still to be discovered.

Knowledge of the endocannabinoid system began with research in the early 1990’s into the effects of cannabis. In the process, the work of other cannabinoids, like CBD, also captured researchers’ attention. They found that cannabinoids are not just something that people consume, but they are naturally produced by the body itself. 

Because the work began with an interest in the effects of cannabis, they named the biological system they discovered after the substance that inspired the research.

Endocannabinoids and Exogenous Cannabinoids

Endocannabinoids are compounds that the body manufactures entirely on its own. They are responsible for the homeostasis, or the ideal balance, of many body functions. They regulate just about every function of the body.

Exogenous cannabinoids come from outside the body. CBD oil and marijuana are two examples of exogenous cannabinoids that can have very different effects on the body’s homeostasis.

The Three Parts of the Endocannabinoid System

The endocannabinoid system is made up of three parts working together in a smooth, self-regulating way. If there’s a breakdown in that natural system, such as in disease, exo-cannabinoids like CBD oil have the potential to restore the balance.

The three parts of the endocannabinoid system are: (1) endocannabinoids, (2) cannabinoid receptors, and (3) enzymes that are part of the body’s metabolism.

Endocannabinoids are produced by the body. They’re neurotransmitters that bond with cannabinoid receptors.

Cannabinoid receptors are found embedded in the surface of cells in the brain, spinal cord, and elsewhere in the body. Their function is to regulate our nervous systems, gastrointestinal systems, heart functions, and other things, such as appetite, sleep, pain, and mood.

Metabolic enzymes keep the system clean, ridding the body of cannabinoids that have already served their purpose and are no longer useful to the system.

CB1 and CB2 Cannabinoid Receptors

So far, researchers have discovered two main cannabinoid receptors, which they’ve called CB1 and CB2. Researchers have found these receptors in different parts of the body and they continue to track locations. The consensus at this time is that CB1 receptors are found in many parts of the body, but mostly in the spinal cord and brain. 

There is a heavy concentration of CB1 receptors in the brain. These are the ones that bond with the cannabinoid THC, producing the feeling of being high. CB2 receptors are found in other parts of the body, such as the immune system, GI tract, tonsils, liver, spleen, and other locations.

The biochemistry of the endocannabinoid system is very complex. A full picture of how it works is still under investigation. CB1 and CB2 are called Class A G-Protein coupled receptors. They bind with molecules such as pheromones or hormones and regulate a wide variety of specific functions. The endogenous cannabinoids produced by the body are called ligands, and these send signals to the receptors, literally enabling cells to “talk” to each other.

Other Cannabinoid Receptors

There are other cannabinoid receptors in addition to CB1 and CB2. Over the last two decades, scientists have found at least 8 other “atypical” receptors that they can track to specific body functions. More have been found but haven’t been fully identified yet. Here are some of the ones they’ve found and what they know about them so far.

GPR18 receptors are found mostly in the spinal cord, but also in immune cells, bone marrow, lungs, testes, and elsewhere. When these receptors are activated, they can lower blood pressure and bolster the immune system’s migration of cells.

GPR55 receptors are widely distributed throughout the body which gives them many functions. They’re found in the central nervous system, gastrointestinal system, liver, lungs, bladder, kidneys, bone marrow, and uterus. Like GPR18, these receptors lower blood pressure and reduce inflammation. These receptors function as moderators of incoming and outgoing energy, and researchers are investigating their effect on diabetes, obesity, and possibly osteoporosis.

GPR119 receptors are only found in a few parts of the body, particularly in the gastrointestinal tract and pancreas. Researchers believe that are most related to metabolism. When these receptors are activated by one of the endocannabinoids in particular, OEA, they regulate food intake, weight loss, and levels of sugar in the blood.

TRVP1, the Vanilloid receptors, relate to pain and are heat-activated sensors of possible tissue damage. Current research explores how this receptor affects pain. It’s believed that when it’s not regulated, it results in chronic pain.

5-HT is a category of many serotonin receptors. The 5-HT3 receptor is best known for its role in limiting nausea and vomiting, as in the effects of chemotherapy.

Other receptors have also been identified, including GlyRs, glycine receptors and PPARs, peroxisome proliferator-activated receptors. GlyRS are related to transmission of pain signals to the brain. PPARs are believed to be involved in a lot of functions, including reduction in weight, nicotine addiction, and inflammation, protection against tumors and neurodegeneration.

Summary of the Endocannabinoid System

In spite of all the modern advances in medical knowledge and research, the endocannabinoid system wasn’t even discovered until the early 1990s. Research into the endocannabinoid system is still in the early stages and each year there are new insights into what the endocannabinoid system does in regulating body homeostasis.

Much of this research involves how cannabinoids affect healing and this information is being used in drug development and treatment. It is clear that there is still a great deal to be discovered, and many possibilities from this research for improved health in the future.