Fig. 2.

SRN-003-556 prevents okadaic acid-induced tau hyperphosphorylation in rat hippocampal slices in a dose-dependent manner. Four hundred fifty-micrometer slices were prepared from hippocampi of adult Wistar rats in artificial cerebrospinal fluid buffer. SRN-003-556 was added 90 min before addition of okadaic acid (1 μM final concentration). After another 90 min, the slices were extracted and analyzed by Western blotting with phosphospecific antibodies: AP422, AT8, anti-pSer262, and Tau-1, which detects tau protein when unphosphorylated at residues 189–207. For normalization to total tau, blotted proteins were dephosphorylated exhaustively on the blot with excess alkaline phosphatase and reprobed with Tau-1.