GABA does not protect cerebro-cortical cultures against excitotoxic cell death

The effects of gamma-aminobutyric acid (GABA) and selective agonists of GABAA and GABAB receptors were examined on excitotoxic cell death evoked in primary cultures of the rat cerebral cortex by glutamate and related excitotoxins. The activity of lactate dehydrogenase released from irreversibly damaged cells into the culture medium was taken as a measure of cell death. Neither GABA nor its agonists protected the cerebro-cortical cells against the toxicity caused by glutamate, N-methyl-D-aspartate, quisqualate and kainate. It is concluded that the cerebro-protective activity of GABA demonstrated in situ involves indirect mechanisms rather than a direct effect on vulnerable cells.