People produce endocannabinoids—similar to compounds found in marijuana—that are critical to many bodily functions

Over the past two decades, a great deal of attention has been given to marijuana—also known as pot or weed. As of early 2023, marijuana has beenlegalized for recreational use in 21 statesand Washington, D.C., and the use ofmarijuana for medical purposeshas grown significantly during thelast 20 or so years.

But few people know that thehuman bodynaturally produces chemicals that are very similar to delta-9-tetrahydrocannabinol, or THC, the psychoactive compound inmarijuana, which comes from theCannabis sativaplant. These substances are called endocannabinoids, and they'refound across all vertebrate species.

Evolutionarily, the appearance of endocannabinoids in vertebrate animals predates that ofCannabis sativabyabout 575 million years.

It is as if the human body has its own version of a marijuana seedling inside, constantly producing small amounts of endocannabinoids.

The similarity of endocannabinoids to THC, and their importance in maintaininghuman health, have raised significant interest among scientists to further study their role in health and disease, and potentially use them as therapeutic targets to treat human diseases.

THCwas first identifiedin 1964, and is just one of more than 100 compounds found in marijuana that arecalled cannabinoids.

Endocannabinoids were not discovereduntil 1992. Since then, research has revealed that they are critical for many important physiological functions thatregulate human health. An imbalance in the production of endocannabinoids, or in the body's responsiveness to them,can lead to major clinical disorders, including obesity as well as neurodegenerative, cardiovascular and inflammatory diseases.

Weare immunologistswho have beenstudying the effects of marijuana cannabinoids and vertebrate endocannabinoidson inflammation and cancer for more than two decades.Research in our laboratoryhas shown that endocannabinoids regulate inflammation and other immune functions.

What is the endocannabinoid system?

A variety of tissues in the body, including brain, muscle, fatty tissue andimmune cells,produce small quantities of endocannabinoids. There aretwo main types of endocannabinoids: anandamide, or AEA, and 2-arachidonoyl glycerol, known as 2-AG. Both of them can activate the body's cannabinoid receptors, which receive and process chemical signals in cells.

One of these receptors, called CB1, isfound predominantly in the brain. The other, called CB2, isfound mainly in immune cells. It is primarily through the activation of these two receptors that endocannabinoids control many bodily functions.

The receptors can be compared to a "lock" and the endocannabinoids a "key" that can open the lock and gain entry into the cells. All these endocannabinoid receptors and molecules together are referred to as the endocannabinoid system.

The cannabis plant contains another compound called cannabidiol, or CBD, which has become popular for its medicinal properties. Unlike THC, CBD doesn't have psychoactive properties because itdoes not activate CB1 receptors in the brain. Nor does itactivate the CB2 receptors, meaning that its action on immune cells is independent of CB2 receptors.

Role of endocannabinoids in the body

The euphoric "high" feeling that people experience when using marijuana comes from THC activating the CB1 receptors in the brain.

But when endocannabinoids activate CB1 receptors, by comparison, they do not cause a marijuana high. One reason is that the bodyproduces them in smaller quantitiesthan the typical amount of THC in marijuana. The other is thatcertain enzymes break them downrapidly after they carry out their cellular functions.

However, there is growing evidence that certain activities may release mood-elevating endocannabinoids. Some research suggests that the relaxed, euphoric feeling you get after exercise, called a "runner's high," results from therelease of endocannabinoidsrather than from endorphins, as previously thought.

The endocannabinoidsregulate several bodily functionssuch as sleep, mood, appetite, learning, memory, body temperature, pain, immune functions and fertility. They control some of these functions by regulating nerve cell signaling in the brain. Normally, nerve cells communicate with one another at junctions called synapses. The endocannabinoid system in the brain regulates this communication at synapses, which explains its ability to affect a wide array of bodily functions.

The elixir of endocannabinoids

Research in our laboratory has shown that某些细胞的免疫系统产生endocannabinoidsthat can regulate inflammation and otherimmune functionsthrough the activation of CB2 receptors.

In addition, we have shown thatendocannabinoids are highly effective in lessening the debilitating effects of autoimmune diseases. These are diseases in which the immune system goes haywire andstarts destroying the body's organs and tissues. Examples includemultiple sclerosis,lupus,hepatitisandarthritis.

Recent research suggests that migraine, fibromyalgia,irritable bowel syndrome,post-traumatic stress disorderand bipolar disease are alllinked to low levels of endocannabinoids.

In a 2022 study, researchers found that a defect in a gene that helps produce endocannabinoids causesearly onset of Parkinson's disease. Another 2022 study linked the same gene defect toother neurological disorders, including developmental delay, poor muscle control and vision problems.

Other research has shown that people with a defective form of CB1 receptorsexperience increased pain sensitivitysuch as migraine headaches and suffer from sleep and memory disorders and anxiety.

The likeness between marijuana and endocannabinoids

We believe that the medicinal properties of THC may be linked to the molecule's ability to compensate for a deficiency or defect in the production or functions of the endocannabinoids.

For example, scientists have found that people who experience certain types of chronic pain may havedecreased production of endocannabinoids. People who consume marijuana for medicinal purposesreport significant relief from pain. Because the THC in marijuanais the cannabinoid that reduces pain,它可能有助于弥补减少d production or functions of endocannabinoids in such patients.

Deciphering the role ofendocannabinoidsis still an emerging area of health research. Certainly much more research is needed to decipher their role in regulating different functions in the body.

In our view, it will also be important to continue to unravel the relationship between defects in theendocannabinoid systemand the development of various diseases and clinical disorders. We think that the answers could hold great promise for the development of new therapies using the body's own cannabinoids.

This article is republished fromThe Conversationunder a Creative Commons license. Read theoriginal article.