Behavioral characteristics of vasopressin-deficient rats (Brattleboro strain)

A group of vasopressin-deficient rats (Brattleboro strain--DI) and a group of normal Long-Evans rats were successively evaluated on visual discrimination, olfactory discrimination, delayed alternation at short and long intertrial intervals (ITIs), approach-avoidance conflict in a straight runway, and open-field behavior. It was found that DI rats adapted more slowly than normal rats in the T-maze, in the straight runway, and they were slower to emerge into the open field. The DI rats were impaired relative to normal animals on the discrimination tasks (visual and olfactory), but they were not impaired on delayed alternation (at least for short ITIs). DI rats also showed better retention of the punishment effect in the approach-avoidance conflict test than normal animals. It is suggested that DI rats have defective reference-memory mechanisms, fairly intact working-memory processes and altered adaptability (timidity or cautiousness).