RAPID LAMINAR-DEPENDENT CHANGES IN GFAP IMMUNOREACTIVE ASTROCYTES IN THE VISUAL-CORTEX OF RATS REARED IN A COMPLEX ENVIRONMENT

Neuronal changes in the visual cortex have previously been found to oc cur within days of housing weanling rats in a complex environment (EC) compared to rats housed in standard laboratory cages (IC). In contras t, layer IV astrocytes immunostained for glial fibrillary acidic prote in (GFAP) have been found to be slow to change. Recent quantitative an alysis has shown the surface density of GFAP immunoreactive (GFAP-IR) astrocytes in young rats to be significantly lower in layer IV in comp arison to layer II/III. In the present study, the analysis of experien ce effects on GFAP-IR astrocytes was extended to include layer II/III as well as layer IV of EC and IC rats. The surface density of GFAP-IR processes was found to be significantly increased within layer II/III after 4-10 days of EC rearing in comparison to IC rats. Consistent wit h previous findings, housing condition did not significantly affect GF AP-IR within layer TV during these early time points. It is possible t hat GFAP immunocytochemistry is not a sensitive means of detecting exp erience-induced early changes in astrocytes within layer IV of weanlin g rats. The rapid astrocytic changes detected in layer II/III are sugg estive of a close relationship between astrocytic plasticity and exper ience-induced synaptic plasticity. Copyright (C) 1996 Elsevier Science Ltd