Effects of amantadine and memantine on NMDA receptor-mediated glutamate toxicity were studied in cultured cerebellar, cortical and mesencephalic neurons. Both drugs protected cerebellar and cortical neurons against glutamate toxicity, memantine being consistently more effective than amantadine but less effective than MK-801. Glutamate toxicity of dopaminergic neurons in mesencephalic cultures was only mildly attenuated by memantine but was also only incompletely blocked by MK-801. These findings suggest that adamantanamines act by inhibiting NMDA receptor-mediated excitatory neurotransmission. However, since non-NMDA receptors appear to be principal mediators of glutamate toxicity of dopaminergic mesencephalic neurons, adamantanamines may fail to protect the nigrostriatal neurons which specifically degenerate in Parkinson's disease.
- N-methyl-d-amphetamine neuron