In the gut, Endocannabinoids are produced by both the serosal and mucosal component of the human intestine, and studies on cell lines have shown that human intestinal epithelial cells can produce endocannabinoids; additional sources of endocannabinoids in the gut include human endothelial cells, platelets, resident macrophages and other immune cells such as lymphocytes. CB1 and CB2 receptors are be upregulated in experimental models of inflammatory bowel disease. In a mouse model of colitis, cannabinoids were found to ameliorate inflammation, and in the human intestine, levels of Anandamide are increased during inflammation. The inflamed small intestine also has significantly elevated activity of FAAH as well as expression of CB1 cannabinoid receptors.