Gliotoxic effects of alpha-aminoadipic acid on monolayer cultures of dissociated postnatal mouse cerebellum.

The cytotoxic effects of DL-, D- and L-alpha-aminoadipic acid, a six-carbon homologue of glutamate, were investigated in cell cultures of dissociated postnatal mouse cerebellum. Treatment with alpha-aminoadipic acid resulted in rapid nuclear and cytoplasmic swelling and, after longer periods of exposure, karyopyknosis of astrocytes, identified by indirect immunofluorescence labelling with anti-human glial fibrillary acidic protein antiserum. The number of astrocytes with pyknotic nuclei depended on the concentration of alpha-aminoadipic acid as well as on the duration of drug action. The presence of 0.21 mM DL-alpha-aminoadipic acid or 0.10 mM L-alpha-aminoadipic acid for 40 h caused karyopyknosis in 50% of the astrocytes. In contrast, D-alpha-aminoadipic acid, had little gliotoxic activity. None of the cytotoxic effects of DL-alpha-aminoadipic acid or L-alpha-aminoadipic acid observed for astrocytes were seen for the neurons present in the cultures when the drug was added after 4 days in vitro. Neurotoxic effects were evident, however, when alpha-aminoadipic acid was included in the culture medium at plating. These results indicate that alpha-adminoadpic acid can be used to substantially reduce the number of astroglia in cerebellar cultures and that dissociated cell cultures will provide a useful model with which to study the mechanisms of alpha-aminoadipic acid induced glial toxicity.