Effects of acute and chronic restraint stress on visceral sensitivity and neuroendocrine hormones in rats.
OBJECTIVE
To investigate the effects of acute and chronic partial restraint stress (PRS) on visceral sensitivity to colorectal distention and the neuroendocrine response in rats.


METHODS
Male Sprague-Dawley rats were used in this study. The abdominal withdrawal reflex score was assessed before stress, immediately after acute or chronic PRS, and 7 days after the first stress. The plasma levels of corticosterone (CORT) and adrenocorticotropic hormone (ACTH) were detected by radioimmunoassay at different time points.


RESULTS
The abdominal withdrawal reflex scores of the rats with acute or chronic PRS were significantly higher immediately after stress than those before and 7 days after the stress (P < 0.05). The levels of CORT (25.35 +/- 6.03 ng/mL) and ACTH (312.47 +/- 50.76 pg/mL) in rats with acute PRS showed a significant elevation immediately after stress compared to rats without PRS (7.24 +/- 2.97 ng/mL, 97.00 +/- 23.33 pg/mL, P < 0.05). However, these hormones returned to the baseline value 7 days after acute PRS. The levels of CORT (20.84 +/- 2.19 ng/mL) and ACTH (200.41 +/- 78.10 pg/mL) in rats with chronic PRS were significantly higher after stress than in rats without PRS (P < 0.05), and these hormones remained elevated 7 days after chronic PRS.


CONCLUSIONS
Both acute and chronic PRS induce reversible visceral hypersensitivity. Acute PRS transiently elevates the plasma levels of CORT and ACTH, whereas chronic PRS has a longer term effect.
Sun
Yan
Y
Division of Gastroenterology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Liu
Feng Ling
FL
Song
Geng Qing
GQ
Qian
Wei
W
Hou
Xiao Hua
XH
D000005:Abdomen; D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D003345:Corticosterone / Q000097:blood*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012007:Rectum / Q000503:physiopathology; D012020:Reflex, Abdominal / Q000502:physiology*; D012149:Restraint, Physical / Q000009:adverse effects*; D013312:Stress, Physiological / Q000503:physiopathology*; D014781:Viscera / Q000503:physiopathology
D000324:Adrenocorticotropic Hormone; D003345:Corticosterone