THE INFLUENCE OF PRENATAL STRESS ON RAT L EARNING

Behaviour was studied of the offsprings of female rats which were expo sed to pain (P) and emotional (PSY) stress during the last 9 days of p regnancy. The P group received 5 electrical footshocks (shuffle thresh old, 50 Hz, 3 sec). PSY rats were placed in the compartment adjacent w ith the grid-floor box, thus they could watch, hear and smell the mate exposed to P, Pups of the intact rats served as a control (C), At 7-8 weeks of age the offsprings were tested in a modified Morris maze, Pe rformance was significantly better in the P group than in the PSY and C groups, Acquisition of avoidance in a one-way shuttle-box at 10-12 w eeks was higher in the P group than in the PSY and C animals, Two week s later, the C rats were more successful in acquisition in a two-way s huttle-box than the PSY and P rats, At the age of 4-5 months a trend w as revealed to higher capacity for learning in female P and C offsprin gs than in males while in the PSY group capacity for learning was sex- independent. The findings suggest that the pain and emotional stress d uring pregnancy exert different effects on behaviour of the offsprings .