Ethological and Vegetative Correlates of Experimental Neurogenic Stress

The study aimed to comprehensively investigate the ethological and vegetative mechanisms involved in the development of experimental emotional stress, establish the relationship between these correlates, and identify an indicator or group of indicators with prognostic value for the occurrence of cardiac dysfunction under neurogenic stress conditions. Materials and Methods. The study presents the results of research on the ethological and autonomic correlates of emotional stress in 254 sexually mature male Wistar rats, using the "afferent excitation conflict" model. Results. Heart rhythm was studied electrocardiographically as an autonomic correlate of emotional stress. The results of the research have shown that ethological and vegetative reactions that perform regulatory and adaptive functions are constant and natural correlates of emotional stress states. The data obtained allow us to note that animals of all three typological groups responded to the onset of stress with a tendency to increase heart rate. Prolonged exposure to the conflict situation was associated with a return of heart rate to baseline values in animals of groups I and II, and a significant decrease in heart rate in animals of group III. Qualitative analysis of the variation curves showed that vagotonic (right position of the variation curve – right graph) prevailed in animals of group I before stress exposure, and sympathotonic (left graph) regulatory influences on the sinus node prevailed in the animals of group III. The onset of stress exposure led to a leftward shift of the variation curves in animals of all groups. However, in animals of group I, this shift was accompanied by a widening of the variation curves (83%), and in animals of group III – by a narrowing (67%). Conclusion. As a result of the studies, four types of heart rate changes were identified during prolonged (3-hour) exposure to stress. A correlation was established between the ethological and typological characteristics of the animals and the occurrence of cardiac rhythm disorders. In animals with a high frequency of cardiac arrhythmias under stress, there was also an increased influence of the sympathetic nervous system on the sinus node, accompanied by a decrease in heart rate variability. Animals with a high frequency of cardiac arrhythmias under stress also showed an increase in the influence of the sympathetic nervous system on the sinus node but with a decrease in heart rate variability.