NBQX DIHYDROXY-6-NITRO-7-SULFAMOYL-BENZO(F)QUINOXALINE) DID NOT AFFECT RECOVERY OF HIGH-ENERGY PHOSPHATES AND PH IN EARLY REPERFUSION IN A RAT MODEL OF TRANSIENT FOREBRAIN ISCHEMIA OR - AN IN-VIVO P-31 NMR-SPECTROSCOPY STUDY

The new non-NMDA (N-methyl-D-aspartate) receptor antagonist NBQX (2,3- dihydroxy-6-nitro-7-sulfamoyl-benzo(F) quinoxaline) has previously bee n shown to exert a neuroprotective effect in animal models of cerebral ischemia when administered in the post-ischemic phase. In this invest igation the effect of NBQX on acidosis and energy recovery in early re perfusion after 10 min of transient forebrain ischemia with the 2-vess el occlusion model in the rat was studied with P-31 NMR spectroscopy I n the intervention group the animals received a bolus dose of NBQX 30 mg.kg(-1) iv at the start of reperfusion. P-31 NMR spectroscopy was us ed to measure intracellular pH, ATP and phosphocreatine continuously i n-vivo during, and after, the ischemic event. The recovery of high ene rgy phosphates and pH was followed during 30 min of reperfusion. Pre-i schemic levels of phosphocreatine were reached after approximately 9-1 0 min in both groups. Although a slight improvement could be seen in t he intervention group there was no significant difference in the rate of recovery between the two groups. ATP reached 90% of preischemic lev els after about 8 min without significant difference between the two g roups. With respect to the recovery of intracellular pH, no difference could be shown. Our results do not contradict previously published re sults, but suggest that the potential protective effect of NBQX is not mediated through improved recovery of energy metabolism in early repe rfusion.