Table 1 Summary of adaptive changes of the endogenous cannabinoid system in experimental models of intestinal dysfunction and in clinical conditions
Experimental/clinical conditionAnimal species/region of gutAdaptive changesReference
Croton oil-induced ileitisMouse, small intestineIncreased CB1 protein expression and FAAH activity. No changes in endocannabinoid levels32
Cholera toxin-induced diarrhoeaMouse, small intestineIncreased levels of anandamide (but not 2-AG) and CB1 mRNA; no changes in FAAH activity26
Acetic acid-induced ileusMouse, small intestineIncreased levels of anandamide (but not 2-AG) and CB1 expression; no changes in FAAH25
Colitis induced by DNBSMouse, colonIncreased number of CB1-expressing neurons33
Colitis induced by oil of mustard or by dextran sulfate sodiumMouse, colonImmunohistochemistry revealed strong upregulation of CB1 receptors in myenteric neurons and endothelial cells; CB2 immunostaining was more marked in infiltrated immune cells in colitis34
Preneoplastic lesions induced by azoxymethaneMouse, colonIncreased levels of 2-AG41
Coeliac-like atrophy induced by methotrexateRat, duodenumIncreased levels of both anandamide and 2-AG (in both muscle/serosa and mucosa layers)37
Toxin A-induced ileitisRat, ileumIncreased levels of anandamide and 2-AG40
Coeliac diseaseHumans, duodenumIncreased levels of anandamide and a trend towards an increase of 2-AG; increased CB1 receptor immunofluorescence37
Colorectal cancer/adenomatous polypsHumans, colonIncreased levels of anandamide and 2-AG; No changes in CB1, CB2 and FAAH expression36
DiverticulitisHumans, colonIncreased levels of anandamide, decreased levels of 2-AG. No changes in CB1 and CB2 mRNA expression38
Inflammatory bowel diseaseHumans, colonMore intense epithelial CB1 immunoreactivity in the acute phase IBD and Crohn’s disease; CB2 receptor immunoreactivity evident in the epithelium of colonic tissue characteristic of IBD; increased levels of anandamide (but not 2-AG)29,35

  • 2-AG, 2-arachydonylglycerol; DNBS, dinitrobenzene sulfonic acid; FAAH, fatty acid amide hydrolase; IBD, inflammatory bowel disease.