Pharmacological characterization of the N-methyl-D-aspartate (NMDA) receptor recognition site in porcine cerebral cortical membranes using [3H]-CGP 39653.
The high-affinity NMDA receptor competitive antagonist [3H]-CGP 39653 binds to Triton X-100 (0.04%) treated porcine cerebral cortex membranes in a saturable and reversible manner, with a KD of 6.1 +/- 0.97 nM and a Bmax of 944 +/- 55 fmol/mg protein. Association of ligand with the recognition site was rapid (estimated k1 = 1.1 x 10(7) M-1 min-1), and a steady state was reached within 30 min of incubation at 4 degrees C. Dissociation was also rapid (estimated k-1 = 0.2 min-1). The pharmacology of the binding site was similar to that for the rat brain, with mean pIC50 values (Hill slopes in parentheses, *indicating significant difference from unity) of 7.54 (0.51*), 6.99 (0.68*), 6.98 (0.71), 6.63 (0.80*), 6.31 (0.62*) and 5.17 (0.78) for R-CPP, L-glutamate, CGS 19755, cis-2,4-methanoglutamate, L-aspartate and NMDA, respectively. Other compounds (glycine, MK-801, kainate, S-AMPA and magnesium ions), previously observed not to interact competitively with the NMDA binding recognition site, showed a low affinity for the porcine cerebral cortex [3H]-CGP 39653 binding site. It is concluded that the pharmacological properties of the NMDA receptor recognition site labelled by [3H]-CGP 39653 are similar in the pig and rat cerebral cortices.
Banks
M D
MD
Astra Pain Control AB, Novum Unit, Huddinge, Sweden.
Sandberg
M P
MP
Fowler
C J
CJ
D015763:2-Amino-5-phosphonovalerate / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects*; D002462:Cell Membrane / Q000737:chemistry; D002540:Cerebral Cortex / Q000737:chemistry* / Q000648:ultrastructure; D005998:Glycine / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007700:Kinetics; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D013552:Swine; D014316:Tritium
D016194:Receptors, N-Methyl-D-Aspartate; D014316:Tritium; C069052:CGP 39653; D015763:2-Amino-5-phosphonovalerate; D005998:Glycine