GRIA2 and Parkinson disease: No significant changes in GluA2 subunit expression were observed in the HD or PD hippocampus dentate gyrus, area CA3, or area CA1, or in the striatal caudate nucleus (HD n = 4, PD n = 5, control n = 5; P > 0.05 in all cases; Figures 3(a)–3(d)).