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World J Gastroenterol. Feb 7, 2008; 14(5): 731-736
Published online Feb 7, 2008. doi: 10.3748/wjg.14.731
Peripheral corticotropin releasing hormone mediates post-inflammatory visceral hypersensitivity in rats
Jun-Ho La, Tae-Sik Sung, Hyun-Ju Kim, Tae-Wan Kim, Tong Mook Kang, Il-Suk Yang
Jun-Ho La, Tae-Sik Sung, Hyun-Ju Kim, Il-Suk Yang, Department of Physiology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
Tae-Wan Kim, Department of Physiology, College of Veterinary Medicine, Kyungpuk National University, Daegu 702-701, Republic of Korea
Tong Mook Kang, Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
Author contributions: La JH and Yang IS designed the research; La JH, Sung TS, and Kim HJ performed the research; La JH, Kim TW and Kang TM analyzed the data; La JH, Kang TM and Yang IS wrote the paper
Correspondence to: Il-Suk Yang, DVM, PhD, Department of Physiology, College of Veterinary Medicine, Seoul National University, San 56-1 Sillim-Dong, Kwanak-Gu, Seoul 151-742, Republic of Korea. isyang@snu.ac.kr
Telephone: +82-2-8801261
Fax: +82-2-8852732
Received: August 15, 2007
Revised: November 24, 2007
Published online: February 7, 2008
Abstract

AIM: To investigate whether peripheral corticotropin releasing hormone (CRH), which is up-regulated in intestinal inflammation, mediates the post-inflammatory visceral hypersensitivity in a rat model of colitis.

METHODS: We measured mucosal myeloperoxidase (MPO) activity as a marker of inflammation, plasma CRH level, and abdominal withdrawal reflex (AWR) to colorectal distension as a visceral nociceptive response at 2, 7 and 14 d after the induction of colitis with 4% acetic acid.

RESULTS: Colonic inflammation, quantified by MPO activity, significantly increased on d 2 and subsided thereafter, which indicated a resolution of inflammation within 7 d. On the contrary, plasma CRH level and AWR score were increased on d 2, remained high on d 7, and returned to control level on d 14. Intraperitoneal injection of a CRH antagonist, astressin (30 &mgr;g/kg), significantly attenuated the post-inflammatory visceral hypersensitivity on d 7. Furthermore, intraperitoneal administration of CRH (3 and 10 &mgr;g/kg) mimicked the post-inflammatory visceral hypersensitivity in naive rats.

CONCLUSION: These results suggest that increased peripheral CRH mediates the enhanced visceral nociception in rats recovered from experimental colitis.

Keywords: Corticotropin releasing hormone; Visceral hypersensitivity; Colitis