[Effect of tissue hypoxia on the structure of cerebral cortex neurons (light--electron microscopic study)]

An examination of the cerebral cortex of rats exposed to sublethal doses of potassium cyanide has revealed changes in the neurons characteristic of the developing histotoxic hypoxia. The neurons of the large hemisphere cortex showed a pronounced hydropic reaction in their cytoplasm with prevalent involvement of the mitochondria. This form of the pathology was observed irrespectively of the duration of the animals live after the poisoning. In rats which survived for a longer time there appeared hyperchromic neurons the number of which gradually increased. This fact was interpreted as addition of the hypoxic state of the neurons to the cyanide intoxication: this was confirmed by development of signs characteristic of hypoxic hypoxia at this stage. The degree of the changes in the mitochondria was found to correlate with the depth of the impairment of vitally important neuron structures. The data obtained show that the primary morphological changes in the neurons develop in their cytomembranes. The degree of the impairment of the mitochondrial membranes can serve as a criterion of reversibility or irreversibility of the pathological process in the nerve cells.