ARE BOMBESIN-LIKE PEPTIDES INVOLVED IN THE MEDIATION OF STRESS RESPONSE?
Section snippets
Material and Methods
Animals. Male Sprague Dawley rats (weighing between 300 and 350 g), obtained from Charles River (St-Constant, Quebec) were used in both experiments. All rats were individually housed and maintained on a 12 h light/dark cycle (with lights on at 6:00 a.m.), with ambient temperature of 23°C and a relative humidity of about 60%. All animals had free access to food (Purina rat chow) and water. Experiments were run in a separate room between 09:00 and 11:00 a.m.
Experiment 1. Rats were randomly
Results
Experiment 1. The ANOVA revealed that BN-like immunoreactivity varied as a function of the interaction between Brain region and Stress duration (F18,165 =2.15; P<0.0069). Tukey's post hoc comparisons revealed that the interaction was attributable to a differential regional responsiveness to the stressor application. In accordance with previously published data, individual brain regions differed significantly in their bombesin-like immunoreactivity, with the highest concentration being detected
Discussion
The objective of the present study was to determine whether the endogenous BN/GRP peptidergic system was involved in the mediation of some of the effects of acute stress. These results demonstrated that acute immobilization stress induced site-specific changes in the endogenous levels of BN-like peptide as well as in BN/GRP receptor density. To our knowledge this is the first account of stress-induced alterations in the BN/GRP system in the brain, and provides evidence supporting the role of
Acknowledgements
This work was supported by a grant from the Natural Sciences and Engineering Research Council of Canada (NSERC) to Z.M. and an MRC studentship to P.K.
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