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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.

Ultrastructural aspects of the secondary brain stem syndrome in patients with hemorrhages and infarcts in the brain hemispheres are considered. The secondary brain stem syndrome is manifested by diverse clinical symptomatology suggestive of dysfunction of different levels of the brain stem: a diminished level of awakening, oculomotor disturbances, changes in the muscle tone and reflexes, cardiorespiratory and other vegetative disorders. Examining the reticular formation of the brain stem under the electron microscope the authors revealed changes in neurons in the form of chromatolysis, an increase in the cellular cytoplasm of the number of lipid inclusions and lysosomes, swelling of mitochondria and (less frequently) the appearance of cells with an elevated osmiophilia of the cytoplasm. Also observed was a systemic increase in lysosomes and lipid granules in capillary structures, and in glial and nervous cells. The pathogenetic factors of secondary brain stem syndrome are discussed.