Behavioural changes in prenatal rats irradiated with low dosage of gamma - rays

The effects of prenatal γ-irradiation on selected behavioural parameters in adult rats were studied. Four-monthold female Sprague-Dawley rats were irradiated with a 1 Gy dose of γ-rays on the 15 th d of gestation. The offspring of both sexes from irradiated (n=26) and non-irradiated mothers (n=36), were tested at the age of 3 months in Morris water maze and open field tests. All the animals showed a tendency to shorten the time needed to reach the platform in the Morris water maze during repeated trials. Statistically significant difference between irradiated and control rats were detected only in males on the 3 rd experimental day. The ability to remember the position of the platform was not altered in irradiated animals after a 4 d break. In open field test, a statistically significant increase in locomotory activities (number of squares entered and in crossings of the central square) was found in irradiated males in comparison with controls. These findings support the results of other authors, that irradiation effects on postnatal behaviour in rats are extremely dependent on the time point of irradiation, and that a correlation exists between the developmental stage of the individual brain structures at time of irradiation, and the late behavioural effects.