The influence of dysosmia simulation on changes in plasma corticosterone and behavior in biological objects

Introduction. Septoplasty simulation in rats provokes changes in the cytoarchitectonics of the hippocampal formation and promotes the release of corticosterone. When exposed to various negative stimuli on the olfactory analyzer, the regulation of the body by the autonomic nervous system changes. The aim of the study was to study the relationship between the type of exposure to the olfactory analyzer, subsequent stress reactions (release of corticosterone into blood plasma) and changes in behavioral reactions in experimental models in rats Material and methods. The first group (control group) (n=10) consisted of intact rats. In the second group, a septoplasty simulation was performed (n=15). Bulbectomy was performed on 19 rats from the third group (n=19). In the fourth group (the predator contact group), each rat was placed once in a cage with a filler freshly fed with cat urine from the same animal (an unsterilized cat aged 26 months) for 10 minutes. The concentration of cortisol in blood plasma was assessed and animals were tested in an open field in the postoperative period. Results. Compared with the 1st control group, in the 2nd group, the concentration of corticosterone in blood plasma in rats was significantly higher throughout the postoperative period (p<0.001). Its maximum occurred at the time of surgery, and in the following days the corticosterone concentration began to significantly decrease (p<0.001). In the bulbectomy group (group 3), after the end of the conditional surgical period, starting from day 15, the concentration of corticosterone in blood plasma in rats was significantly reduced throughout the followup period (p<0.001). In group 4, during the day after exposure, the concentration of corticosterone in the blood of rats was significantly higher than in the control group (p<0.001). Already on the 2nd day after exposure, the values of this indicator significantly decreased compared to the 1st day (p<0.001), and did not differ from the control group. Changes in motor and research activity, anxiety reactions in rats under open field testing conditions after various negative methods of influencing the function of the olfactory analyzer were expressed to varying degrees. In animals, after modeling septoplasty and after contact with a predator, a decrease in research activity was expressed, anxiety, depressive-like states appeared, as well as anxiety. Conclusion. These reactions, compared with intact animals, are probably caused by hyperactivation of the sympathetic nervous system, activation of the hypothalamic-pituitary-adrenal axis. In animals after bulbectomy, research activity is also reduced, but motor activity is increased. This is due to the complete lack of olfactory analyzer function (in the case of septoplasty, it is partially preserved), which causes distress syndrome in animals. © Team of authors, 2024.