How Do Cannabinoids Work?

Cannabinoids are a type of chemical compound that are found in cannabis plants and produced naturally in humans and other animals.  Over a hundred different cannabinoids have been identified to date.

The endocannabinoid system of the human body is made up of cannabinoid receptors found on cells as well as cannabinoid molecules produced by the body, including anandamide and 2-Arachidonoylglycerol (2-AG).  The endocannabinoid system helps to regulate many physiological responses such as pain, mood, and appetite.

In the cannabis plant, there are two major cannabinoids responsible for the effects associated with marijuana: tetrahydrocannabinol (THC) and cannabidiol (CBD).  THC is the main psychoactive cannabinoid found in marijuana, and it mimics the naturally occurring effects of anandamide.  CBD is another major component of the cannabis plant, but it is not psychoactive.

In general, cannabinoids work by attaching to specific cannabinoid receptors found on our cells called CB₁ and CB₂ receptors.  CB₁ receptors are predominantly found in the brain, whereas CB₂ receptors are present in other parts of the body like the immune and gastrointestinal systems.  When a cannabinoid binds to its matching receptor, the brain responds by releasing different amounts of neurotransmitters.  Neurotransmitters are the chemicals that send signals between neurons in the brain.  Cannabinoids therefore impact how our neurons communicate with one another.  THC, CBD, and other cannabinoids all have different effects on these receptors.

THC can bind to both CB₁ and CB₂ receptors.  Its interaction with CB₁ causes a decrease in the amount of GABA neurotransmitter and a corresponding increase in dopamine. Because CB₁ receptors are concentrated in parts of the brain that deal with memory, movement, and coordination, this shift in neurotransmitter release leads to the psychoactive and behavioural changes associated with marijuana use.  While THC and CB₁ receptors lead to the “getting high” feeling, CB₂ receptors most likely mediate some of the medicinal and anti-inflammatory effects observed with cannabis use.

CBD is a little different.  It doesn’t have much attraction for CB₁ and CB₂ receptors, but rather it stimulates the body to release more of its own endogenous cannabinoids like anandamide.  CBD also interacts with other receptors in the body such as vanilloid, adenosine, and serotonin receptors.  Serotonin helps regulate many essential functions such as appetite, sleep, anxiety, and mood.  The fact that CBD attaches to these various receptors may explain the medicinal properties of CBD, like the antidepressant effects of this compound.

Interestingly, CBD is an antagonist for the CB₁ and CB₂ receptors.  This means that it limits how much other cannabinoids like THC can interact with those receptors.  Therefore, CBD may moderate the psychoactive effect of THC, lessening the behavioural effects of THC.  This is a desirable characteristic in many strains that are used for medical purposes, and some strains have been specifically developed to have a higher amount of CBD relative to THC so users don’t feel as high.