The effect of emotional stress on the behavioral and endocrine indices of rats selected for their contrasting capacities for active avoidance

Female rats of two strains selected for high (Koltushi high avoidance, KHA) and low (Koltushi low avoidance, KLA) acquisition of active avoidance of shock in a two-way shuttle-box were exposed to emotional stress accompanied by pain and without it. Emotional stress with pain (electrical paw stimulation) had no effects on behavioural and endocrine responses. It was found out that behaviour of KHA rats with their active behavioural strategy was not affected by the emotional stress without pain. In contrast, KLA rats demonstrated enhanced locomotion and exploratory activity, decreased grooming and anxiety. There were no changes in endocrine stress responses. Our findings suggest putative beneficial effect of emotional stress on the animals with passive behavioural strategy.