Stereospecific acute neuronotoxicity of 'uncommon' plant amino acids linked to human motor-system diseases.

The L-isomer of beta-N-methylamino-L-alanine (BMAA), present in free form in seed of Cycas circinalis, elicits in spinal cord cultures a pattern of acute postsynaptic neuronal vacuolation comparable to that induced by beta-N-oxalylamino-L-alanine (BOAA), an excitotoxic amino acid of greater potency isolated from seed of Lathyrus sativus. The neuronotoxic properties of these compounds may be linked to the etiology of motor-system degenerative disorders (amyotrophic lateral sclerosis and lathyrism, respectively) found in human groups that have used these plant seeds for food.