I₁^PP2A and hyperphosphorylated tau are colocalized and memantine reduces expression of hyperphosphorylated tau.

<p>A,B) GFP served as a reporter protein for AAV1-induced expression. Strong immunofluorescence in the cerebral cortex (Aa-Ad and Am-Ap), the ventricular area (Ba-Bd and Bm-Bp) was observed. Tau was hyperphosphorylated at pT231/pS235 (M4), and pS262/pS356 (12e8) epitopes in the cerebral cortex (Ag, As), the ventricular area (Bg, Bs) of AAV1-I₁^PP2A, but not AAV1-GFP rats (Ae, Aq, Be and Bq). Double immunostaining showed that I₁^PP2A colocalized with hyperphosphorylated tau (Ak, Aw, Bk and Bw). Memantine inhibited tau hyperphosphorylation and phosphorylated tau distribution in the I₁^PP2A rats (Ah, At, Bh and Bt) while memantine didn’t influence the distribution and expression of I₁^PP2A (Ac, Ad, Ao, Ap and Bc, Bd, Bo, Bp). 3–4 rats were employed in each experiment. Scale bar in A and B, 50 μm.