QUISQUALATE-INDUCED EXCITOTOXIC DEATH OF GLIAL-CELLS - TRANSIENT VULNERABILITY OF CULTURED ASTROCYTES

The cytotoxic effect of quisqualate, a potent excitatory amino acid (EAA), was examined in purified astrocyte cultures obtained from neonatal rat cerebral cortex and grown in a serum-free, defined medium (G5). Excitotoxicity was evaluated by phase contrast microscopy and quantified by the measurement of lactic dehydrogenase (LDH) activity released from the damaged cells into the culture medium. Quisqualate evoked not only osmotic swelling, but also cytotoxic cell death of cultured astrocytes. The vulnerability of cells was restricted to a period between day 4 and 8 in subculture, with a maximal sensitivity on day 7. The present findings indicate that not only neurons, but also glial cells may exhibit excitotoxic vulnerability. The vulnerability to quisqualate appears to be a transient phenomenon, at least in cultured astrocytes.