NBQX (6-nitro-sulfamoyl-benzo-quinoxaline-dione) and CPP (3-carboxy-piperazin-propyl phosphonic acid) potentiate dopamine agonist induced rotations in substantia nigra lesioned rats.

Degeneration of dopaminergic nigrostriatal neurons in primate models of Parkinson's disease (PD) leads to an overactivity of excitatory glutamatergic projections from the subthalamic nucleus (STN) to the output nuclei of the basal ganglia resulting in rigidity and akinesia. The selective alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) antagonist 6-nitro-sulfamoyl-benzo-quinoxaline-dione (NBQX) and the competitive N-methyl-D-aspartate (NMDA) antagonist 3-carboxy-piperazin-propyl phosphonic acid (CPP) ameliorate parkinsonian symptomatology when co-administered with threshold doses of L-DOPA in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated common marmosets and induce rotations in rats with unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra (SN). Here we report that in the 6-OHDA-lesioned rat NBQX and CPP induce contralateral rotations when combined with threshold doses of the direct dopamine agonists lisuride or apomorphine. AMPA antagonists and competitive NMDA antagonists may therefore be suitable as adjuvants for the treatment of PD.