CB2 receptor

CB2 receptors, or cannabinoid receptor type 2, is an important part of the endocannabinoid system, a biological network of endocannabinoids, receptors, and enzymes with which cannabis interacts. This type of cannabinoid receptor is expressed primarily in cells of the body’s immune system, whereas CB1 receptors are heavily concentrated in the brain and nervous system. It is believed that CB2 receptors may play a role in regulating immune system responses such as inflammation.

“CB2 receptors are one of several types of cannabinoid receptors.”

What are CB2 receptors?

CB2 receptors refer to a specific type of cannabinoid receptor found in the body. These receptors allow us to experience the subjective and therapeutic effects of cannabis by interacting with its compounds, such as THC and CBD. One cannabis terpene, caryophyllene, appears to also interact with CB2 receptors.

CB2 receptors make up one part of what is known as the endocannabinoid system. This endocannabinoid system functions to maintain balance within our bodies—or homeostasis—and involves various enzymes, receptors, and natural cannabis-like compounds called endocannabinoids.

When we consume cannabis, chemical compounds ether the body which interact with CB2 receptors and catalyze effects in the body, such as a reduction in inflammation. Similar in structure to the cannabinoids in cannabis, the body naturally produces compounds called endocannabinoids which also interact with cannabinoid receptors. These endocannabinoids include chemicals like anandamide and 2-AG.

What do CB2 receptors do?

CB2 receptors are believed to play a role in regulating immune signaling and inflammatory responses throughout the body. Some cannabinoids are believed to carry out anti-inflammatory effects via CB2 receptors, whose activation changes the way signals of inflammation are transmitted. Unlike CB1 receptors, which are abundant in the brain and associated with the experience of feeling high, CB2 receptors are more evenly distributed throughout the body in cells of the immune system.

Contrary to popular belief, CBD does not bind readily to CB2 receptors; CBD demonstrates a weak affinity for CB2. It has a weak affinity for CB1 as well, but CBD does interact with those receptors in non-direct ways by influencing related systems.

The difference between CB1 and CB2 receptors

CB1 and CB2 are the two most well-studied cannabinoid receptor types, though others exist. Both receptor types appear throughout the body but differ somewhat in their local concentration—CB1 receptors appear heavily in the brain, central nervous system, and lungs, while CB2 receptors occur more abundantly in the immune system. 

The activation of these two receptor types appear to have different regulatory functions. CB1 receptors seem to play a role in regulating a broad set of homeostatic functions influencing sleep, appetite, memory, mood, and sensory experience, among others. CB2 receptors are believed to be involved in functions pertaining to immune and inflammation signaling. 

CB1 and CB2 receptors also differ in structure, which affects the way cannabinoids interact with them. For example, THC binds strongly to CB1 receptors but weakly to CB2 receptors.