Ultrastructural changes in the neurons of the cerebral cortex of ondatra in acute hypoxia

The reaction of cells in the sensomotor cortex of the ondatra cerebrum has been studied electron microscopically under acute hypoxia conditions. Certain changes have been revealed in neuronal bodies, dendrites, dendritic spines, as well as in synaptic contacts. Reaction of glial cells is noted. The degree of manifestation of the changes essentially varies in different neurons. In most cells, however, they are of reversible character, despite duration of the hypoxia effect. This is evidently connected with the fact, that the ondatra is a diving animal, which is evolutionary adapted to a periodical deficiency of oxygen. The neuronal changes revealed, nevertheless, are not the signs, specifically caused by hypoxia, they are peculiar for many other effects (deafferentation, influences of neurotoxins, stress etc.).