Prenatal protein malnutrition affects avoidance but not escape behavior in the elevated T-maze test

Abstract

An elevated T-maze was used to study the effects of prenatal protein deficiency on inhibitory avoidance and escape behaviors. Female rats were provided with a 25% (control) or a 6% (low protein) casein diets before and during pregnancy. After birth, eight pups in each litter (six males and two females) were fostered to a lactating well-nourished mother. After weaning (21 days of age) all animals received a lab chow diet. Behavioral testing of these offspring began at 70 days of age. To assess inhibitory avoidance, prenatally malnourished and control rats were placed individually at the end of an enclosed arm in an elevated T-maze (one enclosed and two open arms) and the time taken to emerge from this arm was recorded. The same procedure was repeated in 2 subsequent trials given at 30-s intervals. Thirty seconds after the last of these trials, the rat was placed at the end of one open arm and the time taken to withdraw from this arm was measured, thus estimating escape latency. To assess retention, inhibitory avoidance and escape were measured again 72 h later. Prenatally malnourished males and females did not significantly increase avoidance latency from trials 1-3, in contrast to male and female controls. Only control female rats significantly reduced their avoidance latency on the retention test. No significant differences in escape latency were found between diet groups. These results suggest that prenatal malnutrition results in a reduction of anxiety, and that there are gender-specific responses to this test.