µ-opioid receptor, β-endorphin, and cannabinoid receptor-2 are increased in the colonic mucosa of irritable bowel syndrome patients.

Giovanni DothelLin ChangWendy ShihMaria Raffaella BarbaroCesare CremonVincenzo StanghelliniFabrizio De PontiEmeran A MayerGiovanni BarbaraCatia Sternini
Published in: Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society (2019)
The increased expression of MOR, β-END, and CB2 in the mucosa of IBS patients, where they are localized to immune cells, suggests that opioid and cannabinoid systems play an immune-related compensatory role in visceral pain in IBS patients. Further work is necessary to support this hypothesis.