Neuronal Nitric Oxide Synthase Is Dislocated in Type I Fibers of Myalgic Muscle but Can Recover with Physical Exercise Training

Figure 1

Altered nNOS activity and protein expression. (a) Assessment of NOS activity in trapezius muscle from women with repetitive work tasks (MYA patients and CON) shows loss of activity in sarcolemma and gain of activity in sarcoplasm of large type I fibers compared to type II. Serial sections show NOS activity in black and MHC-I in red. # marks identical fibers on serial sections. Scale bar: 50 μm. (b) Immunohistochemical staining of nNOS and MHC-II from trapezius and vastus lateralis muscle. In trapezius muscle type I fibers show reduced sarcolemma-localized nNOS protein and greater sarcoplasmic nNOS protein (*) compared with type II fibers. Vastus lateralis did not show this type of alterations. nNOS in red, myosin heavy chain II in green, and a merged image with DAPI in blue. I and II mark identical type I and type II fibers, respectively. Scale bar: 50 μm.

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