For examination of the influence of many pharmacological substances with psychotropic activity on the behavioral structure of rabbits we used two experimental models. In the first we investigated the spontaneous behavior, by event-recorded method in 2 hours, and in the second we studied behavior under stress conditions (between stimulation of the ventromedial hypothalamus nucleus, evoked every 10 min). The behavioral structure was estimated in the following phases (each of them changing aperiodically):

• tension (assuming the immobile standing position with increased muscle tension and quickened breathing),
• orientation-searching (sniffing at the experimental cage, watching the surroundings with either moving about or not, sometimes trying to leave the cage),
• comfort (assuming a resting position, mostly in a horizontal position, napping or falling asleep now and again),
• grooming (body cleaning with the tongue and paws, rubbing against the cage walls),
• food uptake (eating and coprophagy), and
• water uptake.

The spectrum of behavioral activity of the rabbits in either of the models - in comparison - showed a significant prolongation of the tension phase at the expense of all the others in the stress conditions (p<0.01). The control experiments, however, have not shown any influence of a solvent (distilled water, starch solution) on the behavior of the rabbits. By administration of various pharmacological substances - potential anxiolytics (in different doses and in different ways: intravenously, intraperitoneally, intranasally, into the lateral ventriculus of the brain; and in different time before the experiment, dependent on the way of treatment), we have, first of all, investigated their influence on the behavior of the rabbits in the stress situation - "good" drugs shortened the tension phase and prolonged the other phases of the animals' behavior. The investigation under spontaneous conditions has provided information about possible negative side effects of some substances, for instance, sedation which was visible in prolongation of the comfort phase, weakened attention manifested in the shortened of orientation-searching), or in the change of food tastes (shortened or prolonged water and food uptake). All substances taken by us into the experiment (fragment of the ACTH 4-10, cyclic analogue of ACTH 5-14, tuftsin analogue TP-7 including tripeptide Pro-Gly-Pro in its structure, derivative of bensodiazepine BD-158, new antioxidant CM-46 from the group of mercaptobenzimidazol) showed a significant anxiolytic effect in the stress situation (p<0.05), but only TP-7 has not changed the normal behavioral structure of the rabbits in spontaneous conditions.