Cannabinoid Receptors: CB1 & CB2

Apr 17th 2024

By now, most people are familiar with the idea that CBD and THC can have psychological and physiological benefits, but how exactly do these compounds cause a reaction in our bodies?

In a 1988 study conducted at the St. Louis University School of Medicine, researchers Allyn Howlett and William Devane discovered that mammalian brains contain receptor sites that respond to cannabinoids. These receptors, the CB1 and CB2 receptors, turned out to be some of the most abundant types of neurotransmitter receptors in the body!

The activation of these receptors by cannabinoids is what causes the psychological and physiological reactions of the endocannabinoid system. CB1 and CB2 receptors are activated by phytocannabinoids like CBD, THC, CBG, etc, as well as by endocannabinoids like Anandamide and 2AG. The cannabinoids act as a key, where the receptor is a lock - once the key turns the lock, a response is triggered in the body.

CB1 receptors are primarily found in the brain and central nervous system, while CB2 receptors are dispersed throughout the body's peripheral organs and immune system.

The CB1 Receptor:

The CB1 receptor consists of 472 amino acids, and is one of the most abundant receptors in the central nervous system - particularly in the neocortex, hippocampus, basal ganglia, cerebellum and brainstem. CB1 receptors are also found "on peripheral nerve terminals and some other areas, such as the testis, eye, vascular endothelium and spleen." Activation of the CB1 receptor can help with issues relating to memory, emotional regulation, pain, and motor control.

The CB2 Receptor:

CB2 receptors consist of 360 amino acids, and occur "mainly on immune cells, but also have been detected in the central nervous system, where they are associated with inflammation, addiction and synaptic plasticity." Activation of the CB2 receptor can help modulate inflammation and immune responses. By regulating the body's dopamine production, activation of the CB2 receptor has also been known to help govern behaviors associated with reward and addiction.

CBD in particular has an interesting relationship with our cannabinoid receptors. While most cannabinoids will directly bind to either the CB1 or CB2 receptor, CBD does not bind to either receptor, but in fact influences other receptors in a way that researchers still don't fully understand. The introduction of CBD can influence the body's production of endocannabinoids, and can increase the likelihood of cannabinoids binding to the CB1 and CB2 receptors.

"CBD also acts as a CB1 'agonist', whereby it inhibits the receptor’s activity...CB1 is the receptor THC 'binds' to. Therefore, there’s scope to suggest CBD suppresses THC when it attaches itself to the CB1 receptor, negating some of its intoxicating effects."

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