Immunocytochemical analysis of mGluR5 in the hippocampus of APP, α-syn, and α-syn/APP tg mice. Vibratome sections were immunostained with an antibody against mGluR5. A. Low- and high-magnification photomicrographs of the CA3 and CA1 regions of the hippocampus from non-tg, APP, α-syn, and α-syn/APP tg mice immunoreacted with anti-mGluR5. Endogenous mGluR5 was observed in a punctate pattern in the neuropil of CA1 and CA3 in the non-tg mice. In the CA3, but not the CA1 the APP, α-syn, and α-syn/APP tg mice had mGluR5 in the neuronal cell bodies, and the punctate staining in the neuropil was significantly enhanced. B. Corrected optical densitometry analysis of the hippocampal CA3 region revealed that mGluR5 was significantly enhanced across all tg mice compared to non-tg mice α-syn, and mGluR5 was significantly increased in the α-syn/APP double tg line compared with the α-syn single tg line. C. In the CA1, there was no significant difference in the amount of mGluR5 in any of the tg line compared to the non-tg line. D. Confocal imaging of CA3 hippocampus double-labeled with α-syn and mGLuR5 confirmed the presence and increase in mGluR5 with α-syn in both the α-syn and α-syn/APP tg mice. Scale bars = 10 and 50 μm for the low and high magnifications, respectively. * = p-value < 0.05 by one-way ANOVA and Dunnett’s post hoc analysis compared to non-tg mice. # = p-value < 0.05 by one-way ANOVA and Tukey-Kramer post hoc analysis when, compared to α-syn/APP tg mice. For each analysis, N = 6 (3–4 months old) mice from each line were utilized.