AMPA and kainate-operated channels reconstituted in artificial bilayers.

Cationic channels which can be activated by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) and kainate play a key role in the generation of excitatory postsynaptic potentials in the brain of all vertebrates. On a protein carrying binding sites for both these ligands, affinity-purified from the Xenopus nervous system, electrical measurements have been performed to investigate its functional properties after the pure complex had been incorporated into planar lipid bilayers. Domoate, AMPA or kainate added to the reconstituted protein activated cationic channels, which were blocked by typical antagonists for this neurotransmitter system. These data suggest that the reconstituted protein is an ionotropic receptor of the unitary non-NMDA subtype.