Light and electron microscopy investigation of glycoconjugates of rat hippocampus by lectin-gold technique

The distribution of glycoconjugates in rat hippocampus was investigated by light and electron microscopy using gold-labelled lectins with different sugar specificities: ConA, WGA, PNA and LTA. A morphological correlation with cytochemical data was performed, and revealed the presence of intensely-stained (dark), unstained (light) and weakly-stained (intermediate) neurons both in Ammon's horn and in the dentate gyrus. The glycoconjugates are located in the nucleus, the perikaryal cytoplasm and the cytoskeleton of axons and dendrites: they are probably involved in the mechanisms of transport towards the synaptic membrane. The presence or absence of glycoconjugates corresponds to the particular ultrastructural aspect of the cell. This suggests the existence of different functional states of the neurons, probably correlated with the synthesis of neurotransmitter precursors or receptors.