The behavior of vasopressin-deficient rats (Brattleboro strain)

Seven Brattleboro rats homozygous for diabetes insipidus (DI) and seven normal Long-Evans (LE) rats were tested on a neuropsychological test battery comprised of the following tasks: time-spent-eating in two adaptation boxes, time-to-emerge into an open field, adaptation to a T-maze, contingently reinforced T-maze alternation, olfactory and visual discrimination, runway learning, approach-avoidance conflict, step-through passive avoidance, prod burying, and stress-induced interference. It was found that DI rats adapted more slowly than LE rats to novel environments (e.g., adaptation box, T-maze, and runway), and DI rats were slower to emerge into an open field. However, DI rats performed as well as LE rats on all other tasks. These results suggest that DI rats have altered temperamental dispositions (timidity or cautiousness), normal working and reference memory, and similar susceptibility (compared to LE rats) to the interfering effects of inescapable stress.