Fine structure of synapses in the hippocampus of the rabbit with special reference to dark presynaptic endings

  • Y. Ibata
  • N. Otsuka


The stratum radiatum of h3 and h4 in the hippocampus of the rahbit, where the mossy fiber endings are distributed, was investigated under the electron microscope. These regions contain a certain number of electron dense presynaptic endings. These are characterized by highly dense synaptic vesicles and mitochondrial matrices. The dense endings are not considered as degenerated. Electron dense silver particles, substituted for zinc, occurred on the synaptic vesicles of these dense terminals as well as the mossy fiber endings after the application of Timm's histochemical method modified for electron microscopy. It is concluded that the dark synaptic endings observed might represent mossy fiber terminals in a special functional phase, or might be the result of structural alteration in the course of tissue preparation. The zinc localized in the synaptic vesicles is thought to be associated with the neurotransmitter present in these endings.


Zinc Fine Structure Synaptic Vesicle Structural Alteration Tissue Preparation 
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Copyright information

© Springer-Verlag 1968

Authors and Affiliations

  • Y. Ibata
    • 1
  • N. Otsuka
    • 1
  1. 1.Department of AnatomyKyoto Prefectural University of MedicineKyotoJapan

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