PRENATAL PROTEIN-MALNUTRITION AFFECTS EXPLORATORY-BEHAVIOR OF FEMALE RATS IN THE ELEVATED PLUS-MAZE TEST

To study the effects of prenatal protein deficiency in the exploration of the elevated plus-maze, an ethological procedure was used. Female rats were provided with 25% (control) or with 6% (low-protein) casein diets before and during pregnancy. After birth eight pups in each litt er (six males and two females) were fostered to a control mother. Afte r weaning (21 days of age) all animals received a lab chow diet until behavioral testing began at 70 days of age. Individual prenatally maln ourished (n = 12) and well-nourished (n = 12) females were placed at t he center of the elevated plus-maze and allowed to explore for a 5-min session. One session was given per day for 6 consecutive days, The fo llowing variables were recorded: percentage of open arm entries; perce ntage of time spent in open arms; total arm entries; time in the cente r platform; latency to first open arm entry; number of attempts to ent er an open arm; number of rearings; number of head-dips. The results s howed a significant effect of malnutrition on six behaviors (percent o pen arm entries, percent time spent in open arms, attempts to enter op en arms, rearings, head-dips, and latency to first open arm entry) and a significant diet by session interaction on two behaviors (attempts to enter open arms and head-dips). These results indicate increased ex ploration of the open arms in prenatally malnourished as compared with well-nourished control rats, suggestive of lower anxiety and/or a hig her impulsiveness in these animals.