AMINO-ACIDS AS DIETARY EXCITOTOXINS - A CONTRIBUTION TO UNDERSTANDINGNEURODEGENERATIVE DISORDERS

The possibility that some acidic amino acids occurring naturally or as additives in the diet can act as excitotoxins producing central nervo us system pathology has been the subject of extensive debate in the la st 20 years and is here reviewed. High doses of glutamate, aspartate o r related excitatory amino acids given in isolation to neonatal rodent s produce acute degeneration in periventricular organs. Neuropathology resulting from consumption of glutamate or aspartate has not been des cribed in man. Various unusual amino acids of plant origin can produce acute excitotoxic syndromes. In man domoate (consumed in mussels that have fed on (Nitschia pungens) can produce an acute syndrome associat ed with limbic system lesions and anterograde amnesia. Kainate and dom oate produce similar syndromes in rodents; acromelate produces spinal pathology. The mechanisms and manifestations of chronic excitotoxicity are less clearly established. A combination of impaired energy metabo lism or impaired buffering of calcium and free radicals and endogenous or exogenous excitotoxins may contribute to neuronal loss in human ne urodegenerative disorders.