Sensitization of the colonic response to novel stress after
previous stressful experience.
Stam, Ruben, Gerda Croiset, Louis M. A. Akkermans, and Victor M.
Wiegant.
Department of Medical Pharmacology, Rudolf Magnus Institute for
Neurosciences, Utrecht University, 3508 TA Utrecht, The
Netherlands
APStracts 3:0231R, 1996.
Stressful life events may be important causative or precipitating
factors for functional gastrointestinal disorders such as the
irritable bowel syndrome in humans. In the rat, a single session of
footshocks is known to sensitize the behavioral and hormonal
responses to subsequent stress, but intestinal responses have not
been investigated. Rats were fitted with bipolar electrodes on
proximal colon and exposed to a single session of footshocks (10 _ 6
s in 15 min, preshocked) or no shocks (control). Weight gain after
footshocks was identical to that in controls. Two weeks after
footshocks, basal colonic spike burst frequency did not differ from
controls or from that recorded before shock treatment. Unlike
controls, however, preshocked rats showed a significant increase in
colonic spike burst frequency to a novel stressful challenge in the
home cage, an electrified prod. Since the behavioral responses to
this challenge did not differ, colonic hyperresponsiveness in
preshocked rats may represent a form of stress-induced autonomic
sensitization. The model should be a useful tool to study mechanisms
and pharmacotherapeutic approaches of the gastrointestinal
consequences of traumatic stress.
Received 18 December 1995; accepted in final form 13 May 1996.
APS Manuscript Number R799-5.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 28 June 96