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

Summary & key facts

This paper reviews what scientists know about a part of the body’s cannabis system called the CB2 receptor that sits in the gut. The authors say CB2 seems to help calm gut inflammation, slow or normalise abnormal gut movement, and reduce gut pain. Unlike the better-known CB1 receptor, CB2 does not cause the “high” tied to marijuana. The review calls CB2 a promising target for future treatments of inflammatory gut conditions, but it also notes that CB2’s role in the gut is not yet fully worked out.

Key facts:

• The paper is a review, meaning the authors looked at and summarized many studies about the CB2 receptor in the gut.
• CB2 receptors are present in the gastrointestinal tract and are linked to the immune system’s control of inflammation there.
• Activating CB2 receptors seems to limit intestinal inflammation and reduce visceral (internal organ) sensitivity and pain.
• CB2 also appears to help regulate abnormal gut movement, which can affect symptoms like cramps or diarrhea.
• Unlike CB1 receptors, which cause psychoactive effects (the “high” from marijuana), CB2 does not have those psychotropic effects, making it an attractive drug target.
• The authors say CB2 acts like a braking system that helps resolve inflammation, but they also note that its functions in the gut are not yet fully characterized.

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