Functional characteristics ofl-glutamate,N-methyl-d-aspartate and kainate receptors in isolated brain synaptic membranes

Abstract
L-Glutamic acid (l-Glu) and other excitatory amino acids and amino acid analogs enhanced [35S]thiocyanate (SCN) uptake in isolated-resealed synaptic membrane vesicles. The SCN uptake was used as a measure of membrane depolarization to evaluate the characteristics of functional excitatory amino acid receptors in the synaptic membranes.N-Methyl-d-aspartate (NMDA) andl-Glu produced additive effects on SCN accumulation indicating the presence of distinctl-Glu and NMDA receptors. On the other hand, kainic acid (KA) andl-Glu shared either common receptor sites or ion channels. The effects of antagonists on NMDA,l-Glu, and KA stimulation of SCN influx were consistent with previously reported electrophysiologic observations in intact neurons.