<p>(A) SH-SY5Y cells were treated with vehicle (VEH) or 0.01 to 10 µM H<sub>2</sub>O<sub>2</sub> for 5 min. Following drug treatments, cell lysates were evaluated by Western blot analysis as described in Materials and Methods. Data were normalized to total TrkB protein expression and are expressed as the fold change (average ± S.E.M.) in TrkB phospho-816 immunoreactivity compared to vehicle-treated cells. Representative blots for phospho-TrkB Y816 (pY816) and TrkB at 145 kDa are shown. (B) Cell cultures were incubated with 0.1 µM 5-HT for 0, 1, 2, 5, 10, or 15 min, and fold change in TrkB Y816 phosphorylation was measured with respect to vehicle. (C) Cultures were pretreated with vehicle or 1000 µM of the ROS scavenger <i>N</i>-acetyl-l-cysteine (NAC) for 45 min followed by treatment with vehicle or 100 nM 5-HT for 5 min. Normalized data was analyzed for phospho-TrkB Y816. (D) Cells were incubated overnight with 0.01 or 0.1 µg/mL pertussis toxin (Ptx) followed by 5 min treatment with 0.1 µM 5-HT. (E) Cell cultures were pretreated with vehicle or 1 or 10 µM of the PDGF receptor kinase inhibitor AG 1296 for 45 min followed by treatment with vehicle or 100 nM 5-HT for 5 min. Western blots were evaluated for changes in phospho-TrkB Y816. (Data are representative of 5-6 independent experiments. * = p < 0.05 compared to vehicle-treated cells; # = p < 0.05 compared to 5-HT-treated cells, one-way ANOVA, Tukey post-test).</p
