STRESS-INDUCED ENHANCEMENT OF COLITIS IN RATS - CRF AND ARGININE-VASOPRESSIN ARE NOT INVOLVED

Because exacerbation of colitis seems to be associated with stress, we proposed evaluating the influence of stress and the involvement of co rticotropin-releasing factor (CRF) and arginine vasopressin (AVP) on e xperimental colitis in rats. Partial restraint stress was applied duri ng 4 consecutive days, before or after intracolonic 2,4,6-trinitrobenz enesulfonic acid (TNB) instillation (15 mg) in rats. Finally, two grou ps of rats were centrally injected with alpha-helical CRF-(9-41) (5 mu g) or AVP antagonist (5 mu g) before each session of stress. Stress w as applied before or right after TNB enhanced colitis, with an increas e in macroscopic and histological scores and myeloperoxidase activity. alpha-Helical CRF-(9-41) or AVP antagonist had no effect on TNB-induc ed colitis but enhanced the effects of stress on colitis. These result s show that stress may exacerbate experimental colitis in rats and tha t CRF and AVP are not responsible for this effect.