FIGURE 2.

Immunoreactivity of phospho-TrkB receptor induced by D1 receptor agonist in rat striatal neurons. A–N, striatal cultures were treated with control (PBS), SKF38393 (SKF), or BDNF at 37 °C on DIV5. Some dishes were preincubated with K-252a or SCH23390 (SCH) prior to SKF38393 incubation. The cultures were fixed and immunostained with phospho-TrkB antibody (red) and dopamine D1 receptor antibody (green). Note that phospho-TrkB immunoreactivity was detected in 87 ± 11% of D1 receptor positive neurons (data not shown). O, specificity of phospho-TrkB antibody was measured by using HEK293-TrkB cells. To assess specificity of phospho-TrkB antibody, cell lysates (30 μg/each) obtained from HEK293-TrkB cells treated with control (PBS) or BDNF (10 ng/ml) for 5 min were probed with phospho-TrkB antibody as well as the antibody that was preincubated with either a phosphorylated or nonphosphorylated TrkB peptide competitor. WB, Western blotting.