Fig. 1

Two-dimensional images of labeled endplates (red) on type-identified muscle fibers with anti-myosin heavy chain (green) from 24-month-old rat. The acetylcholine receptor area was stained in red, and the surrounding area was determined as the outer border of the acetylcholine receptor area marked with white dashed line (a). Muscle diameter is indicated by a yellow arrow (a). These data were used to calculate the endplate normalized area and endplate surrounding area. White bar indicates 30 μm