Cannabinoid CB2 receptors in the gastrointestinal tract: a regulatory system in states of inflammation

Summary & key facts

This paper reviews evidence that a particular part of the body's cannabis system, called the CB2 receptor, exists in the gut and seems to help calm inflammation, reduce pain from the gut, and slow down abnormal gut movement. Unlike the better-known CB1 receptor, CB2 does not cause the mind‑altering effects of marijuana. Because of that, drugs that activate CB2 might be useful for inflammatory gut problems, but researchers say we still need more studies because CB2’s roles in the gut are not fully worked out yet.

Key facts:

• This article is a review, meaning the authors looked at many studies to summarize what we know about CB2 receptors in the digestive tract.
• CB2 receptors are present in the gastrointestinal tract and seem to act as a “brake” that helps resolve inflammation there.
• Activating CB2 receptors can reduce abnormal gut movement, lower inflammation in the intestine, and decrease visceral sensitivity and gut pain in studies so far.
• CB2 receptors do not produce the psychoactive, mind‑altering effects that come from activating CB1 receptors, which are the ones linked to the high from marijuana.
• Because CB2 can affect immune activity and gut movement without causing a high, researchers say CB2 is a promising target for new treatments of inflammatory gut conditions, but its functions are not yet well characterized and more research is needed.

Abstract

The emerging potential for the cannabinoid (CB) system in modulating gastrointestinal inflammation has gained momentum over the last few years. Traditional and anecdotal use of marijuana for gastrointestinal disorders, such as diarrhoea and abdominal cramps is recognized, but the therapeutic benefit of cannabinoids in the 21st century is overshadowed by the psychoactive problems associated with CB1 receptor activation. However, the presence and function of the CB2 receptor in the GI tract, whilst not yet well characterized, holds great promise due to its immunomodulatory roles in inflammatory systems and its lack of psychotropic effects. This review of our current knowledge of CB2 receptors in the gastrointestinal tract highlights its role in regulating abnormal motility, modulating intestinal inflammation and limiting visceral sensitivity and pain. CB2 receptors represent a braking system and a pathophysiological mechanism for the resolution of inflammation and many of its symptoms. CB2 receptor activation therefore represents a very promising therapeutic target in gastrointestinal inflammatory states where there is immune activation and motility dysfunction.

Topics

Cannabis and Cannabinoid Research Infant Health and Development Sleep and Wakefulness Research

Categories

Health Sciences Medicine Pharmacology

Tags

Agonist Biology Cannabinoid Cannabinoid receptor Cannabinoid receptor type 2 Endocannabinoid system Gastrointestinal tract Genetics Immune system Immunology Inflammation Internal medicine Medicine Motility Pharmacology Receptor

Substances

Cannabis

Conditions & symptoms

Chronic Pain Chronic pain Poor appetite or overeating