The goal of this work was to establish the effects of irradiation of the head with gamma-rays on selected forms of innate behavior, as well as on the habituation process to new environment in the open field test in rats. During a 5-day control period behavioral parameters reflecting motoric and explorative activities, as well as anxiety (6 parameters in total) were followed daily in 20 male Sprague-Dawley rats in an open field. Fourteen animals were repeatedly tested after irradiation of the head with a single dose of 10 Gy of gamma-rays. The results showed statistically significant depression of motoric and explorative activities during the first 3 days after irradiation in comparison with the control period. After irradiation the level of anxiety was elevated. Habituation to a new environment was observed in non-irradiated, but not in irradiated animals. These results suggest that the applied dose of ionizing radiation influenced the brain centers involved in control of innate behavioral functions connected with response to a new environment in rats.
The aim of this study was to assess, whether a sublethal dose of gamma-rays will influence the avoidance behaviour and anxiety in rats and whether the response to radiation depends on time of day of its application. Adult male Wistar rats were tested in elevated plus-maze, in hot plate test and in the light/dark box in 4 regular intervals during a day. After two weeks the animals were irradiated with a whole-body dose 6 Gy of gamma-rays. One day after irradiation the animals were repeatedly tested in the same way, as before irradiation. In the plus-maze test an increased level of anxiety was established. The irradiation significantly decreased the locomotor activity of rats, but the extent of exploratory and comfortable behaviour were not altered. After irradiation, an elevated aversion to the thermal stimulus was observed in the hot plate test. The effects of radiation were more pronounced in the light period of the day, than in the dark one. No significant differences in aversion to light were detected after irradiation. The obtained results indicate, that sublethal doses of ionizing radiation can markedly influence the reactivity of animals to adverse stimuli, their motoric activity and emotional status, as well.