DISTURBANCES OF EMOTIONAL STATES BY NEUROGEN STRESS AND SOME WAYS OF THEIR CORRECTION

Shevereva V.M.

Department of Physiology of Ontogenesis, Kharkov National University, Institute of Biology, 4. Svobody pl., Kharkov, 66077, Ukraine

The problem of disturbances of emotional states and their correction is one of the most burning at this stage in the medico-biological research. The keen interest of scientists in the problem is due to the fact that emotiogenic mechanisms of the brain are involved in the pathological processes occurring in times of prolonged violent effort and emotion. Disturbances of these mechanisms are found to end in desadaptation thus promoting nervous, mental, and somatic disorders. Simulation of the stress-induced emotional states and their manifestations offers promise as a method of studying the neurogenic mechanisms. These models meeting clinical practice needs may be also a great help in seeking the adequate ways to correct the disturbances.

For this purpose, the investigations have been made by a group of scientists from Ukrainian Research Institute of Experimental and Clinical Neurology & Psychiatry and Research Institute of Biology, Kharkov National University. Using a model of neurogen stress, it has been shown that

i) chronic emotional stress gradually produces profound changes in bioelectrogenesis of limbic-neocortical structures of brain. In EEG, they can be seen as hypersynchronic electrical waves and hippocampal theta-rhythms, neocortical desynchronization, components of convulsive reactions or decreased electrical activity of the brain and stable suppression of biopotentials;

ii) chronic emotional stress gradually decreases the thresholds of negative emotional reactions (active avoidance) initiation, changes the neutral and positive emotiogenic hypothalamic zones into the negative and ambivalent ones and may enhance the ambivalent properties of self-stimulation. The response of the positive emotions system to the stress effects is ambiguous. As the suppression of the brain biopotentials progresses, the decrease in activity of the positive emotiogenic zones of ventrolateral hypothalamus (self-stimulation) is observed;

iii) cessation of the stress action does not restore the original electric activity and emotional behavior of animals for a long period of time. Moreover, it has been found that after a lapse of time the general functional state of the rats investigated can also be affected. Character and intensity of stress-induced disturbances, different time for their initiation and restoration are mainly defined by the individual features of the animals;

iv) stimulation of the positive emotiogenic zones of ventrolateral hypothalamus in the post-stress period can decrease the negative impacts of the stress and contributes largely to a restoration of original emotional states;

v) transcranial micropolarization by small direct current activates the positive emotions system, exerts inhibiting (modulating) effect on cerebral mechanisms of negative emotional reactions and initiates a synchronization of biopotentials and sleep. In old animals, the positive consequences appeared after the above procedure had been repeated some times. The modeled emotional disturbances ´feelª the antistress effect of the polarization through the mediation of the positive emotions system and mechanisms of general physiological activity, So, such effects of brain polarization can be considered as the theoretical prerequisites for its wider application in a management of nervous and mental diseases treatment;

vi)under neurogen stress the beta-adrenoblocker, obsidan, suppresses the manifestations of bioelectric, emotional and vegetative stress components, thus regulating and normalizing the excitability level of structural-functional (neocortical and limbico-reticular ones) which are responsible for initiation of the reactions of the emotional-stress character.

In conclusion it may be said that chronic emotional stress gradually changes the electrical brain activity and emotional states of animals. Removal of stress action can enhance the manifestations of bioelectric and emotional stress components.

For archive of summaries of bio-medical researches from Kharkov (Ukraine) universities and institutes contact: Nataliya Babenko, Head of Department of Physiology of Ontogenesis, Institute of Biology, Kharkov National University, e-mail: babenko@univer.kharkov.ua, fax: (0572)352923.