TrkB and p-TrkB antibody specificity in TrkB-deficient neuromuscular junctions and motoneuron terminals. (A) NMJs in the Transversus abdominis anterior (TVA) of control and Ntrk2^−/− P5 animals stained against TrkB (gray), Synaptophysin-1 (SYP, magenta), and postsynaptic ACh receptors (BTX, green), scale bar: 10 µm. Dotted line depicts outline of the presynapse (SYP signal). Normalized mean gray values of TrkB (N = 2, n = 24). (B) Growth cones from control and Ntrk2^−/− motoneurons stained against TrkB (gray) and SYP (magenta); scale bar: 5 µm. Normalized mean gray values of TrkB (N = 1, n = 40). (C) Growth cones from control and Ntrk2^−/− motoneurons stained against surface TrkB (gray) and SYP (magenta); scale bar: 5 µm. Normalized mean gray values of surface TrkB (N = 1, n = 20). (D) Growth cones from control and Ntrk2^−/− motoneurons unstimulated and 15 min BDNF stimulated stained against p-TrkB (gray) and SYP (magenta); scale bar: 5 µm. Normalized mean gray values of p-TrkB (N = 2, n = 40). Data are presented as scatter dot plot with bar. Bars represent the mean ± SD.