Objective. The effect of antidepressant bupropion on the behavior of rats subjected to chronic mild unpredictable stress was investigated. Rats with opposite coping styles — active and passive — were subjected to stress. Materials and methods. In the population of outbred animals Wistar were isolated individuals with the opposite coping styles on the basis of the acquisition of active avoidance. The animals of these two groups were tested in the Porsolt’s test and in the elevated plus-maze, and then subjected to chronic stress. Results. Behavioral deficits were more pronounced in rats with initial active coping style. After administration of bupropion behavior in the Porsolt’s test was restored only in rats with initially active coping style. On the behavior of animals with an initially passive coping style, bupropion had no impact. Conclusion. Our findings suggest the different nature of post-stress disorders in animals with different active and passive coping styles.

The results of behavioral tests of laboratory animals are highly variable. Even within the same laboratory the results of the same test can differ significantly. We tested the effect of the experimenter's smell -male and female -on the behavior of male Wistar rats. The smell donors were clinically healthy non-smoking, low-alcohol-consuming volunteers aged 20-21: four men, and four women in the luteal phase of the menstrual cycle. They wore cotton socks and T-shirts at night, which, in the morning, were sealed in plastic bags. The animals were tested on the same day. In the first experiment (n = 20), smell samples were placed in the center of the elevated zero maze. First, we tested naive animals, after 20 days in the presence of a male smell, and after another 20 days in the presence of a female smell. The presence of human body smells during testing increased the rats' anxiety. A male smell had a greater effect than a female smell. In the second experiment (n = 29), the delayed effect of exposure to human smells was studied. The home cages were equipped with perforated plastic containers with fabric inside. They remained in the cages for one hour. During exposure to the smell, the animals were aroused, which was manifested in an intensive examination of containers and multiple agonistic contacts. Four hours later, increased anxiety was noted only after exposure to a female smell. The obtained data show that the results of behavioral tests on laboratory rats may depend, inter alia, on the sex of the experimenter.