cgp-39653 and ferrous-chloride

Quinolinic acid (QUIN) displaced binding of agonist and antagonist ligands for the N-methyl-D-aspartate (NMDA) receptor in rat brain synaptic membranes. Both QUIN and glutamic acid (GLU) potentiated binding of [3H]dizocilpine (MK-801) in the presence of glycine (GLY) alone, whereas the potentiation by QUIN was in a bell-shaped fashion in contrast to that by GLU. However, further addition of spermidine (SPD) induced bell-shaped potentiation by GLU as well as QUIN. The potentiation by QUIN was markedly deteriorated by the further addition of FeCl2 irrespective of the presence of GLY and SPD added. These results suggest that QUIN may potentiate [3H]MK-801 binding to the open NMDA channel in rat brain synaptic membranes through a mechanism different from that underlying the potentiation by GLU.

Topics: 2-Amino-5-phosphonovalerate; Allosteric Regulation; Animals; Binding Sites; Brain; Dizocilpine Maleate; Excitatory Amino Acid Antagonists; Ferrous Compounds; Glutamic Acid; Glycine; Inhibitory Concentration 50; Kynurenic Acid; Male; Quinolinic Acid; Rats; Rats, Wistar; Receptors, N-Methyl-D-Aspartate; Spermidine; Synaptic Membranes