Comparison of the patterns of full-length α-synuclein in the hippocampus of APP, α-syn, and α-syn/APP tg mice. Vibratome sections were immunostained with rabbit polyclonal antibody against full-length total α-syn (Millipore) 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-syn. Endogenous α-syn was observed in a punctate pattern in the neuropil of CA1 and CA3 in the non-tg and APP tg mice which was significantly enhanced in the α-syn and α-syn/APP tg mice. Moreover, α-syn and α-syn/APP tg mice also had α-syn in the neuronal cell bodies. B. Corrected optical densitometry analysis of the hippocampal CA3 region revealed that α-syn was significantly enhanced in both the α-syn and α-syn/APP tg mice compared to non-tg mice α-syn, and α-syn was significantly increased in the α-syn/APP double tg line compared with the α-syn single tg line. C. In the CA1, the increase in α-syn in α-syn tg line was equivalent to the increase in the α-syn/APP double tg line, which were both significantly increased compared to non-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.