NBQX, a competitive non-NMDA receptor antagonist, reduces degeneration due to focal spinal cord ischemia.

We have used the laser-induced photochemical thrombosis model in adult rats to evaluate the significance of the non-N-methyl-D-aspartate (non-NMDA) subtype of glutamate receptors in situations of focal spinal cord ischemia. The animals were pretreated with the selective non-NMDA antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)-quinoxaline (NBQX) or, for comparison, the NMDA antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5-10-imine (MK-801). Neurological function was quantified using evaluations of motor score and inclined plane. The MK-801-treated rats had higher motor scores during the 3-week observation period while NBQX-treated rats only performed significantly better at 1 week. Both treatments caused significantly better performance in the inclined plane test. NBQX and MK-801 reduced the volume of necrosis by approximately 47% at 3 weeks postlesion. We conclude that blockade of both NMDA and non-NMDA subtypes of glutamate receptors reduces ischemic necrosis, possibly by preventing excessive stimulation of these receptors by released excitatory amino acids in the lesion area.