[The effect of prenatal "pain" and "emotional" stresses on the learning characteristics of rats].

Behaviour was studied of the offsprings of female rats which were exposed to pain (P) and emotional (PSY) stress during the last 9 days of pregnancy. The P group received 5 electrical foot shocks (shuffle threshold, 50 Hz, 3 sec). PSY rats were placed in the compartment adjacent with 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. Performance 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 weeks was higher in the P group than in the PSY and C animals. Two weeks later, the C rats were more successful in acquisition in a two-way shuttle-box than the PSY and P rats. At the age of 4-5 months a trend was revealed to higher capacity for learning in female P and C offsprings than in males while in the PSY group capacity for learning was sex-independent. The findings suggest that the pain and emotional stress during pregnancy exert different effects on behaviour of the offsprings.