Ion channel properties of a protein complex with characteristics of a glutamate/N-methyl-D-aspartate receptor

The functional reconstitution of glutamate receptor proteins purified from mammalian brain has been difficult to accomplish, However, channels activated by L-glutamate (L-Glu) and N-methyl-D-aspartate (NMDA) were detected in planar lipid bilayer membranes (PLMs) following the reconstitution of a complex of proteins with binding sites for NMDA receptor (NMDAR) ligands, The presence of glycine was necessary for optimal activation, A linear current-voltage relationship was observed with the reversal potential being zero, Channels activated by L-Glu had conductances of 23, 47 and 65 pS, and were suppressed partially by competitive and fully by noncompetitive inhibitors of NMDARs. Magnesium had little effect on the reconstituted channels.