Functional reconstitution of N-methyl-D-aspartate receptors in artificial lipid bilayers

Functional reconstitution of the N-methyl-D-aspartate (NMDA) receptors was achieved by adding synaptic membranes from rat brain to large planar bimolecular lipid membranes (BLMs). The reconstituted receptors exhibited several properties of the NDMA receptors described using a variety of biochemical and electrophysiological techniques. Addition of NMDA at concentrations between 5 and 50 microM produced large, voltage-dependent increases in membrane conductivity. The selective antagonist of NMDA receptors, amino-2-phosphonopentanoate (AP-7), totally blocked the response of the bilayers to NMDA as did micromolar concentrations of magnesium; this latter effect was also voltage-dependent. These results indicate that BLMs can be used to study the ion channels and regulatory processes associated with NMDA receptors from adult brain in ways that could not be accomplished with conventional neurophysiological techniques.