Cytochemical Redistribution of 5′-Nucleotidase in the Developing Cat Visual Cortex

Authors

  • S. W. Schoen,

    1. Department of Neurophysiology, Max Planck Institute for Brain Research, Deutschordenstraße 46, W-6000 Frankfurt 71, FRG. Department of Neuromorphology, Max Planck Institute for Psychiatry, W-8033 Martinsried, FRG
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    • 4

      Department of Neurology, Aachen University School of Medicine, W-5100 Aachen, Germany

  • G. W. Kreutzberg,

    1. Department of Neuromorphology, Max Planck Institute for Psychiatry, W-8033 Martinsried, FRG
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  • W. Singer

    Corresponding author
    1. Department of Neurophysiology, Max Planck Institute for Brain Research, Deutschordenstraße 46, W-6000 Frankfurt 71, FRG.
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Professor W. Singer, as above

Abstract

The adenosine-producing ectoenzyme 5′-nucleotidase has recently been shown to undergo a marked redistribution during development of the cat visual cortex and to be involved in the remodelling of ocular dominance columns (Schoen et al., J. Comp. Neurol., 296, 379 – 392, 1990). Using an enzyme-cytochemical technique, we now investigate the developmental redistribution of 5′-nucleotidase activity in area 17 of kittens at the ultrastructural level. Between postnatal days 35 and 42, when 5′-nucleotidase is concentrated in layer IV, enzyme reaction product occupies the clefts of asymmetrical synapses within the neuropil. During later development (9th and 13th postnatal weeks), when 5′-nucleotidase spreads over all cortical laminae, the enzyme disappears from its synaptic localization and becomes increasingly associated with astrocytic membranes. The transient appearance of 5′-nucleotidase at synapses parallels the time-course and laminar profile of the synaptic remodelling which takes place during the critical period of visual cortex development. This suggests that synapse-bound 5′-nucleotidase activity plays a role in synaptic malleability, whereas its later association with glial profiles is likely to reflect other functions of the enzyme.

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