[3H]MK-801 binding to NMDA glutamatergic receptors in Parkinson's disease and progressive supranuclear palsy

The interactions existing between glutamatergic and dopaminergic systems, notably in the basal ganglia, suggest that glutamatergic antagonists may have therapeutic interest in extrapyramidal disorders characterized by impaired dopaminergic transmission. The binding of [3H]dizocilpine maleate (MK-801) to glutamate receptors of the N-methyl-D-aspartate (NMDA)-subtype was characterized in temporal and frontal cortex, in hippocampus and in subcortical areas (caudate nucleus and putamen) from controls and patients with Parkinson's disease or progressive supranuclear palsy. The binding affinity (KD) and the maximal specific binding capacity (Bmax) of [3H]MK-801 were unchanged in all the cerebral regions studied in both diseases. This indicates the existence of preserved NMDA glutamate receptors, which is required for potential therapeutic efficacy of specific antagonists.