[Ultrastructural changes in the brains of rats after sustaining acute emotional stress].

The ultrastructure of the neurones and synapses of the parietal area of the cortex and reticular formation of the brain of rats was studied after emotional stress induced by 2-hour immobilization, as well as 1 and 24 hours after discontinuance of immobilization. Two types of ultrastructural changes were revealed. Some of the changes were reversible and functional in nature and were largely pertinent to the alterations on the cytoplasma part, with these alterations being appreciably reduced 24 hours after the discontinuance of immobilization. The other ones (vacuolization of neuronal nuclei and marked changes in the synapses) were more pronounced and resistant and were seen 24 hours after the immobilization was discontinued. It is suggested that stable changes that do not disappear 24 hours after the immobilization stress might form the pathomorphological basis for the clinical syndromes of cerebrovisceral disorders that develop during long-term periods after the stress.