INTERACTION OF SOME PLANT HETEROCYCLIC BETA-SUBSTITUTED ALANINES WITHRAT-BRAIN N-METHYL-D-ASPARTATE (NMDA) RECEPTORS

The neuropharmacological actions of some plant heterocyclic beta-subst ituted alanines on rat brain N-methyl-D-aspartate (NMDA) receptors wer e studied. Of the compounds tested, 3-N-oxalyl-L-2,3-diaminopropanoic acid (beta-ODAP), the causal agent of human neurolathyrism, exhibited an inhibitory activity on the NMDA receptor binding assay at a relativ ely high concentration (IC50: 4.7 x 10(-5) hr). The biochemical precur sor of beta-ODAP, beta-(isoxazolin-5-on-2-yl)-L-alanine (BIA) was inac tive in this assay. These results suggest that beta-ODAP, the neurotox in of Lathyrus sativus, in addition to its excitatory action on lpha-a mino-3-hydroxy-5-methylisosazole-4-propanoic acid (AMPA) receptors, al so has neurotoxic potential through its action on NMDA receptors.