Fig. 1.

Different staining patterns are observed in different fibers of a mixed muscle stained with an antibody to a Golgi complex protein. Single fibers were prepared from rat soleus (a) or red gastrocnemius (b–d) and stained with anti-GM130. Images, focused at the surface of the fibers (left panels) or 5- to 6-μm-deep in the core of the fibers (right panels) were collected with a conventional fluorescence microscope. Insets give an enlarged view of a single nucleus (left) or of an equivalent area in the core (right).Arrows point to the position of nuclei (a–c) or of nuclear poles (d).Filled arrowheads point to the Golgi complex of nonmuscle cells, and open arrowheads to stretches of staining in the core of fibers. The dark channels that can be seen at the surface of the fibers in a and ccorrespond to the position of blood vessels. Notice that the RG fiber shown in b has a pattern very similar to that in the soleus, both at the surface and in the core of the fiber. Fibers shown in c and d present a different pattern in which nuclei are not highlighted by the staining. Scale bar, 50 μm.