Cytochemical redistribution of 5'-nucleotidase in the developing cat visual cortex.
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.
Schoen
S W
SW
Department of Neurophysiology, Max Planck Institute for Brain Research, Frankfurt, FRG.
Kreutzberg
G W
GW
Singer
W
W
D015720:5'-Nucleotidase / Q000378:metabolism*; D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002415:Cats; D006651:Histocytochemistry; D008854:Microscopy, Electron; D014018:Tissue Distribution; D014793:Visual Cortex / Q000201:enzymology* / Q000254:growth & development / Q000648:ultrastructure
D015720:5'-Nucleotidase