Fig. 3. Formation and function of NMJs. (A) -bungarotoxin (red) stained NMJ of diaphragm muscle of 4-weekold mice. Mature NMJ in wild-type (left) and mutant (right) mice showed the typical pretzel-like structure. (B) ß-dystroglycan (green) and (C) utrophin (green) were expressed in the postsynaptic membrane of NMJs of soleus muscle and co-localized with -bungarotoxin (red) in both wild-type (left) and mutant (right) mice. (D) Miniature endplate currents were decreased in amplitude by 15% in mutant mice when compared with wild-type mice, while decay time constants (E) were similar (means±s.e.; data from 37 wild-type and 39 mutant endplates, from five wild-type and six mutant diaphragms), as shown in these representative recordings. (F) Quantitative immunofluorescence of -bungarotoxin-labeled AChRs at NMJs of diaphragm muscle reveals decrease in AChR density by about 20% in mutant mice (means±s.e.; data from 27 wild-type and 27 mutant endplates, from five wild-type and five mutant diaphragms), consistent with the reduction in mepc. amplitude observed in electrophysiological recordings. Scale bars: 3 µm in A-C.