Changes in Hippocampal Ultrastructure After Ischemia with Long Survival Times

  • P. Bonnekoh
  • U. Oschlies
  • K.-A. Hossmann


The hippocampal morphology after 5-min forebrain ischemia was investigated by electron microscopy in the gerbil. Survival times of up to 10 months were studied. After 3 weeks of recirculation, the number of pyramidal neurons in the CA1 sector had decreased to about 6%, a value which did not further change after 6 or 10 months survival. Neuronal death was followed by a marked shrinkage of all CA1 layers becoming obvious after 6 months. Electron microscopy after 3 weeks of recirculation showed normal and morphologically altered neurons in the CA1 pyramidal layer. There were “pale” and “dark” type injured neurons present. After 6 and 10 months only the pale type was observed. CA1 stratum radiatum consisted of intact presynaptic terminals even after 10 months of recirculation. After the long survival times the astrocytic population in the CA1 sector was characterized by huge fiber bundles.

The presence of intact presynaptic terminals and reactive astrocytes lying side by side may be of importance for the development of chronic changes after acute neuronal damage in this region.


ischemia hippocampus Mongolian gerbil selective vulnerability recirculation Time 


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© Springer-Verlag Berlin Heidelberg 1992

Authors and Affiliations

  • P. Bonnekoh
  • U. Oschlies
  • K.-A. Hossmann

There are no affiliations available

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