Behavioral and endocrine change following chronic predatory stress.

Adult male rats showed very high levels of crouching when exposed to a cat, with suppression of the nondefensive behaviors (e.g., lying, locomotion, rearing) that were shown by toy cat-exposed controls.

Chronic social stress alters levels of corticotropin-releasing factor and arginine vasopressin mRNA in rat brain.

In the visible burrow system model of chronic social stress, male rats housed in mixed-sex groups quickly form a dominance hierarchy in which the subordinates appear to be severely stressed. A subgroup of subordinates have an impaired corticosterone response after presentation of a novel restraint stressor, leading to their designation as nonresponsive subordinates. To examine the mechanism underlying the blunted corticosterone response in these animals, in situ hybridization histochemistry was used to quantify corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) mRNA expression in the brain.