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Cytochemical redistribution of 5'-nucleotidase in the developing cat visual cortex
S W Schoen1, G W Kreutzberg, W Singer
1Department of Neurophysiology, Max Planck Institute for Brain Research, Frankfurt, FRG.
The European Journal of Neuroscience
|March 1, 1993
Summary
The enzyme 5'-nucleotidase redistributes during kitten visual cortex development. It transiently localizes to synapses during critical periods, suggesting a role in synaptic plasticity, then shifts to glial cells.
Area of Science:
- Neuroscience
- Developmental Biology
- Enzymology
Background:
- 5'-nucleotidase is an adenosine-producing ectoenzyme.
- This enzyme shows redistribution during cat visual cortex development.
- It is implicated in the remodeling of ocular dominance columns.
Purpose of the Study:
- To investigate the developmental redistribution of 5'-nucleotidase activity.
- To examine this redistribution at the ultrastructural level in kitten visual cortex area 17.
Main Methods:
- Enzyme-cytochemical technique was employed.
- Ultrastructural analysis was performed on kitten visual cortex.
Main Results:
- Between postnatal days 35-42, 5'-nucleotidase concentrated in layer IV and occupied asymmetrical synaptic clefts.
- Later, in the 9th and 13th postnatal weeks, the enzyme redistributed across cortical laminae.
- The enzyme disappeared from synapses and became associated with astrocytic membranes.
Conclusions:
- Transient synaptic localization of 5'-nucleotidase parallels synaptic remodeling during the visual cortex critical period.
- Synapse-bound 5'-nucleotidase activity likely contributes to synaptic malleability.
- Later association with glial cells suggests alternative functions for the enzyme.