Ultrastructure of the rat hippocampus after isobaric respirative hyperoxia

After exposing rats to an environment of isobaric hyperoxia, the ultrastructural alterations of the hippocampus were studied. No major alterations were found in the nerve cells. Of importance was the moderate osmiophilia and the spindle-like transformation of the mitochondria. Vacuolated synapses and neuraxons were found, containing amorphous material. Astrocytic perivascular end feet were found vacuolated in many places. Many endothelial cells of the capillaries presented high osmiophilia, which sometimes prevented structural details. Quantitatively, the findings were proportionally related to the time of exposure in the pure oxygen atmosphere (24, 48 and 65 hours).