Nitric oxide synthase I (NOS-I) is deficient in the sarcolemma of striated muscle fibers in patients with Duchenne muscular dystrophy, suggesting an association with dystrophin.
Previously, we have demonstrated the expression of the brain-type nitric oxide synthase (NOS-I) in the sarcolemmal region of somatic and visceral striated muscle fibers in a variety of mammalian species through the use of enzyme histochemical and immunochemical techniques. Here we report that NOS-I protein and its NADPH diaphorase (NADPHd) activity are co-localized in the sarcolemma of human skeletal muscles. NOS-I immunolabeling and NADPHd activity showed no significant variation between type I and II fibers. In muscle biopsy specimens from patients with Duchenne muscular dystrophy (DMD), both NOS-I protein and activity were absent or markedly reduced. We, therefore, propose that NOS-I is complexed with dystrophin and/or dystrophin-associated proteins, adding a novel member to the sarcolemmal dystrophin-glycoprotein complex (DGC). The nature of the NOS-I-DGC link, and its role in skeletal muscle physiology and pathophysiology remain to be elucidated.
Grozdanovic
Z
Z
Department of Anatomy, Konigin-Luise-Strasse, Berlin, Germany.
Gosztonyi
G
G
Gossrau
R
R
D002648:Child; D016189:Dystrophin / Q000378:metabolism*; D019085:Fluorescent Antibody Technique, Direct; D006801:Humans; D007150:Immunohistochemistry; D018485:Muscle Fibers, Skeletal / Q000201:enzymology* / Q000648:ultrastructure; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000473:pathology / Q000648:ultrastructure; D009136:Muscular Dystrophies / Q000201:enzymology* / Q000473:pathology; D009252:NADPH Dehydrogenase / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000172:deficiency*; D012508:Sarcolemma / Q000201:enzymology*
D016189:Dystrophin; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase