IBD: Patients with IBD find symptom relief in the Cannabis field

Abstract

Cannabis (or marijuana) has been used in traditional medicine to treat intestinal inflammation and is used as a self-medication by patients with inflammatory bowel disease (IBD). A survey by Ravikoff Allegretti et al. at a specialized IBD clinic shows that, in the US, marijuana is used by a significant number of patients with IBD to alleviate their symptoms.

Fig. 1. Scheme of the endocannabinoid system

The endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) are synthesized and released on demand in a paracrine fashion. N-arachidonoylphosphatidylethanolamine (NAPE) needs arachidonic acid as a precursor and is cleaved by a phospholipase D (NAPE-PLD) into AEA. The key enzyme in synthesizing 2-AG from diacylglycerol (DAG) is diacylglycerol lipase (DAGL). AEA and 2-AG primarily activate cannabinoid receptors (cannabinoid receptor 1 and 2; CB₁, CB₂) but AEA may also act as a ligand for the transient receptor potential cation channel 1 (vanilloid receptor 1; TRPV1) and the G protein-coupled receptor 55 (GPR55). The existance of an endocannabinoid transporter (EMT) is still controversial. The main enzyme in degrading AEA is fatty acid amide hydrolase (FAAH) while 2-AG is degraded by monoacylglycerol lipase (MAGL). The EMT, the GPR55 and the TRPV1 receptor may not be part of the endocannabinoid system in a close sense but were added to the system as they are responsive to and involved in the action of exo- and endocannabinoids.