SELECTIVE ABLATION OF ASTROCYTES BY INTRACEREBRAL INJECTIONS OF ALPHA-AMINOADIPATE

The efficacy and the specificity of the putative astrotoxin, alpha-ami noadipate, were examined in this study. The integrity of astrocytes wa s evaluated at several time points following a single injection of alp ha-aminoadipate into amygdala of adult rats using immunohistochemistry . The density and the morphological appearance of neurons and the resp onse of microglia were also examined. The injection of alpha-aminoadip ate disrupted the astrocytic network in that region. There was a profo und loss of glial fibrillary acidic protein-positive and S100 beta-pos itive astrocytes, normally present in the region, while vimentin immun ohistochemistry revealed the presence of deformed cell processes, pres umably astrocytic. The presence of reactive microglia at the injection site was suggestive of an active degenerative process, while the norm al neuronal density and appearance, as compared to controls, suggested that the damage was confined to astrocytes. The confirmed effectivene ss and cellular specificity of alpha-aminoadipate in vivo makes it a p otentially important experimental tool for attempting to decipher the functional significance of astrocytes. (C) 1996 Wiley-Liss, Inc.