Frolova G. Analysis of neurochemical mechanisms of psychical depression induction on the background of emotional stress

This work covers the theoretical ground of phenotypic distinctions of psychoemotional states and their dynamics under conditions of emotional stress and pharmacological influences. It is set that psychoemotional state of examined animals in control condition is different. Comparison of quantitative values of behavioral indexes studied allowed distinguishing groups of animals with different levels of anxiety, behavioral activity and depressiveness. It was shown that emotional stress specifically modified behavior of experimental rats with the initially low, middle and high behavioral indexes; social isolation induced development of the depression-similar state more frequently in comparison with immobilization which was expressed in decline of motor and explorative activity, as well as in increase of immobilization time in Porsolt's test. It is first indicated that selective elevation activity of the specific monoaminergic systems of the brain by introduction of L-tryptophan and deprenyl led to rise in depressiveness level in animals with the initially high value of this index. It is also determined that selective pharmacological stimulation of the monoaminergic systems has rendered different, often opposite, influence on the anxiety level and behavioral activity of experimental rats. Is was found that changes in psychoemotional profile of animals' sub-groups with low, middle and high behavioral indexes on the background of selective suppression of synaptic transmission in brain monoaminergic systems by para-chlorophenylalanine, ?-methyl-p-tyrosine and haloperidol, proved to be comparatively more variable and highly depended on the initial level of behavioral indexes that were seen as in increase of general reactivity, as in expansion of spectrum of observed changes. It was ascertained that the changes of psychoemotional profile of sub-groups of rats with low, middle and high behavioral indexes on a background of selective pharmacological elevation or suppression of the monoaminergic systems activity coincided in direction and intensity with the changes occurred due to emotional stress influences. It confirms generality of neurochemical nature of stress-inducible shifts in behavior, resulting in forming the depression-similar state, and supposes the preliminary analysis of phenoltypical distinctions of behavior at prognostication of pharmacological effects of psychoactive drugs.