Crystalloid structures in the neuronal nuclei of the cerebral cortex of rats following total ischaemia.

The study was concerned with the nuclei of neurons derived from the cerebral cortex of rats that underwent experimental cardiac arrest for a duration of 10 minutes and then, after reanimation, survived from 2 weeks up to 10 months. The animals were divided into two groups: in the first-those specimens that survived from 2 to 6 weeks; in the second-those that survived 8 weeks to 10 months. In the specimens obtained from the first group we observed irregular vesicular structures and bundles of parallel fibrils 8 nm in diameter. In the second group we often observed paracrystalline form resembling "plaited ropes" and tubulous structures linked by a microfibrillar netting. These structures were analysed with a gonyometer. We believe that both the paracrystalline and the irregular vesicular structures that have been observed in the neurons obtained from ischaemic brains appeared due to the alterations in the structure of the karyoskeleton and that the observed intracellular structures are not specific for post-ischaemic alterations.