Fig. 3.

TSC number is correlated with terminal area, but most of the postnatal gain in TSC number precedes the gain in endplate area. A, Correlation of nerve terminal area and TSC number in 2-month-old soleus and edl muscles. The correlation coefficient (r) was 0.37 for soleus and 0.68 for edl. R² = 0.14 for soleus and 0.46 for edl. Both are significant with p < 0.01. Nerve terminal area was determined by measuring the area labeled by anti-synaptophysin antibodies. TSC number was determined by colocalization of S-100 and DAPI labeling over the nerve terminal region. B, Change in TSC number (solid line) and endplate area (hatched line) with age in soleus and edl. Data for the change in TSC number with age in soleus are replotted from Figure 2G. Endplate area was determined by measuring the area labeled by binding of rhodamine-conjugated α-bungarotoxin in one set of muscles. The number of TSCs was determined in a second set of muscles by colocalization of DAPI and S-100 labels over synaptophysin-labeled regions. In each set of muscles, three rats from each age group were examined, and a minimum of 30 endplates was examined in each muscle.