Peripheral corticotropin releasing hormone mediates post-inflammatory visceral hypersensitivity in rats.
OBJECTIVE
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 mug/kg), significantly attenuated the post-inflammatory visceral hypersensitivity on d 7. Furthermore, intraperitoneal administration of CRH (3 and 10 mug/kg) mimicked the post-inflammatory visceral hypersensitivity in naive rats.


CONCLUSIONS
These results suggest that increased peripheral CRH mediates the enhanced visceral nociception in rats recovered from experimental colitis.
La
Jun-Ho
JH
Department of Physiology, College of Veterinary Medicine, Seoul National University, San 56-1 Sillim-Dong, Kwanak-Gu, Seoul 151-742, Republic of Korea.
Sung
Tae-Sik
TS
Kim
Hyun-Ju
HJ
Kim
Tae-Wan
TW
Kang
Tong-Mook
TM
Yang
Il-Suk
IS
D015746:Abdominal Pain / Q000209:etiology / Q000276:immunology*; D000818:Animals; D002404:Catheterization; D003092:Colitis / Q000150:complications / Q000276:immunology*; D003106:Colon / Q000276:immunology / Q000294:innervation; D003346:Corticotropin-Releasing Hormone / Q000097:blood* / Q000276:immunology; D004195:Disease Models, Animal; D008297:Male; D009619:Nociceptors / Q000276:immunology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D003346:Corticotropin-Releasing Hormone