Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Role of mucosal mast cells in visceral hypersensitivity in a rat model of irritable bowel syndrome | J. Vet. Sci. 2004 5 4 319-324 JOURNAL OF Veterinary Science Role of mucosal mast cells in visceral hypersensitivity in a rat model of irritable bowel syndrome Jun-Ho La1 Tae-Wan Kim2 Tae-Sik Sung1 Hyun-Ju Kim1 Jeom-Yong Kim3 Il-Suk Yang Department of Physiology College of Veterinary Medicine Seoul National University Seoul 151-742 Korea Department of Physiology College of Veterinary Medicine Kyungpuk National University Daegu 702-701 Korea Institute of Bioscience and Biotechnology Daewoong Pharm Co. LTD. Yongin 449-814 Korea The involvement of mucosal mast cells MMC in the pathophysiology of irritable bowel syndrome IBS is still controversial. We aimed to re-evaluate the role of MMC in visceral hypersensitivity associated with IBS using a rat IBS model that develops the IBS symptom after a subsidence of acetic acid-induced colitis. No significant difference in the number of MMC was observed between normal rat colon and IBS rat colon. mm2 in normal vs. mm2 in IBS p . However the degranulation rate of MMC was significantly higher in IBS rat colon in normal vs. in IBS p . Pretreatment of a mast cell stabilizer doxantrazole 5 mg kg . reduced the degranulation rate of MMC and significantly attenuated visceral hypersensitivity to rectal distension in IBS rat whereas it had no effect on the visceral sensory responses in normal rat. These results suggest that although the number of MMC is not significantly changed in IBS rat colon the higher degranulation rate of MMC is responsible for visceral hypersensitivity in this model IBS. Key words Irritable bowel syndrome visceral hypersensitivity mucosal mast cell. Introduction Irritable bowel syndrome IBS a chronic disorder in the absence of objective abnormalities in structures is the most common disorder encountered by gastroenterologist 6 . Investigators have demonstrated that one of the important pathophysiological features of IBS is a lowered threshold for visceral pain .