Fig. 5

Requirement of muscle activity for Lrp4 β-gal concentration at NMJ. a Diffused synaptic Lrp4 β-gal in denervated TA muscles. Muscle sections (90 µm thick) were prepared from control or denervated lacZ/+ mice at P42 and were subjected to β-gal staining. Red arrow: NMJ localization. Scale bar, 0.8 mm. b Increased mRNA levels of Lrp4 and lacZ in denervated TA muscle. n = 3 mice per group. c Diffused synaptic Lrp4 β-gal in µ-conotoxin-injected muscles. TA muscles were injected with PBS or µ-conotoxin (80 µl, 10 µM) once every 2 days for 5 days. Slices (90 µm thick) were stained with α-BTX (red) and SYN/NF (green), and then subjected to X-gal staining (blue). Scale bar, 0.2 mm. d Enlarged images of AChR clusters from the box in c. Scale bar, 50 µm. e Decreased number of AChR clusters with Lrp4 β-gal cluster in µ-conotoxin-treated muscles. **p = 0.0058. f No change in AChR areas. p = 0.7489. g No change in nerve coverage (red/green). p = 0.8679. h Increased fragments of AChR clusters in µ-conotoxin-treated muscles. ***p < 0.0001. n = 4 mice per group, 30–40 NMJ per mice, unpaired t-test