Figure 2.

A, Expression levels of neurotrophic factors in E14.5 hindlimbs measured by semiquantitative reverse transcription-PCR. B, D, Neuromuscular junctions (NMJ) in the soleus muscle of 1-month-old WT (B) and Bax KO (D) mice. Postsynaptic acetylcholine receptors (AChRs) were labeled with Alexa 594-α-bungarotoxin (red), and presynaptic axons-nerve terminal are labeled green. Nerve terminals overlying AChR appear yellow. Both genotypes show focal innervation of end plates by single axons, and end plate size and morphology are similar. Scale bar: D (for B, D), 20 μm. C, E, Examination of muscle fiber subtype composition using acidic ATPase staining in triceps muscles of WT (C) and Bax KO (E) mice. In this staining procedure, different muscle fibers are stained at different intensities (type 1 < type 2b < type 2a). Scale bar: E (for C, E), 20 μm. F, Quantification of muscle fiber numbers in adult triceps. Five different fields were chosen and different fiber types were counted in each field and then summated. G, The wet weight of adult gastrocnemius and triceps muscles in Bax KO mice and WT littermates. Values are means ± SDs; n = 3 for F and G.