EXTRACTS FROM RHIZOMES OF CYPERUS-ARTICULATUS (CYPERACEAE) DISPLACE [H-3] CGP39653 AND [H-3] GLYCINE BINDING FROM CORTICAL MEMBRANES AND SELECTIVELY INHIBIT NMDA RECEPTOR-MEDIATED NEUROTRANSMISSION

The marshland plant Cyperus articulatus (Cyperaceae) is commonly used in traditional medicine in Africa and Latin America to treat a wide va riety of human diseases ranging from headache to epilepsy. We tested t he hypothesis that the purported anti-epileptic effect of this plant m ight be due to a functional inhibition of excitatory amino acid recept ors. One or several component(s) contained in the extracts inhibited t he binding of [H-3]CGP39653 to the NMDA recognition site and of [H-3]g lycine to the strychnine-insensitive glycine site of the NMDA receptor complex from rat neocortex. Water extracts from rhizomes of Cyperus a rticulatus dose-dependently reduced spontaneous epileptiform discharge s and NMDA-induced depolarizations in the rat cortical wedge preparati on at concentrations at which AMPA-induced depolarizations were not af fected. We conclude that the purported beneficial effects of Cyperus a rticulatus might at least partially be due to inhibition of NMDA-media ted neurotransmission.