A series of sections of a soleus muscle specimen from the SP + C + Th group (non-exercised side). The sections were stained with H&E (A), and processed for SP (antibody sc-14104) (B) and NK-1R (C). Muscle fibers that largely are normal in appearance (asterisk) and muscle fibers that are more or less filled with white blood cells (triangles) (necrotic muscle fibers) are seen. Marked NK-1R and to some extent also SP-like immunoreactions are abservable in the white blood cells that have infiltrated into the necrotic muscle fibers. There are also NK-1R and SP-like immunoreactions in white blood cells located in the connective tissue spaces that separate the muscle fibers. Note that there is also some unspecific autofluoresence reactions in muscle fibers. In the inset in (A), the results of double-staining for NK-1R (above) and desmin (below) are demonstrated. One muscle fiber shows marked NK-1 R immunoreaction but no desmin immunolabelling (triangle), whist others only show unspecific background raction after NK-1 R staining but specific desmin immunolabelling (asterisks). The former fiber can based on desmin reaction pattern be interpreted to be a necrotic muscle fiber. Bars = 50 μm.