Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.5.1.19 (NOS)
7,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent data have shown that NOS-I is localized almost exclusively to the sarcolemma of fast-twitch fibers, where it probably interacts with the dystrophin-glycoprotein complex. The concentration of dystrophin-related protein at the neuromuscular junctions and the possible involvement of NO in synaptic suppression led us to investigate the presence of NOS-I at the adult motor endplates. Our data clearly show that NOS-I protein, detected by immunohistochemistry accumulates at the adult endplates. Furthermore, the absence of NOS-I protein at the denervated neuromuscular junctions suggest a neural origin of this enzyme. The putative roles of NO at the endplate are discussed.
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PMID:Accumulation of NO synthase (type-I) at the neuromuscular junctions in adult mice. 872 75

Previous studies have shown the association of NOS I with the sarcolemma in mammalian striated muscle fibers, implicating the dystrophin complex (DC) as a major anchor for the enzyme. The potential role of the sarcoglycan subcomplex, especially of alpha-sarcoglycan (adhalin), as part of the DC in holding of NOS I in the sarcolemmal position was examined by carrying out a comparative study on the distribution of NOS I, dystrophin, dystrophin-associated glycoproteins (DAG) and alpha-sarcoglycan in various skeletal muscles of non-mammals. Rat muscles were included since they reflect the situation in mammals. Catalytic NOS-associated diaphorase (NOSaD) activity as well as NOS I and DAG immunoreactivities were positive in the saracolemma region of skeletal muscle fibers of rats, chicken, and turtles. Adhalin immunoreactivity was present in the rat but absent in the chicken and turtle muscle surface membrane. These data suggest that alpha-sarcoglycan and therefore the entire sarcoglycan subcomplex may not be needed for localizing NOS I to the sarcolemma in these non-mammalian species. This may hold for skeletal muscle fibers in general.
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PMID:Adhalin (alpha-sarcoglycan) is not required for anchoring of nitric oxide synthase I (NOS I) to the sarcolemma in non-mammalian skeletal (striated) muscle fibers. 886 63

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.
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PMID: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. 905 90

Recently, it has been shown that in human striated muscle the signalling enzyme, brain-type nitric oxide synthase I (NOS I), is associated with the sarcolemma and complexes with dystrophin and/or members of the dystrophin complex. In order to find out whether there exists a regular association between NOS I and the complex, muscle biopsies from patients with various muscle disorders were analysed by enzyme histochemistry and immunohistochemistry. In patients suffering from Duchenne muscular dystrophy, and to a lesser extent in those with Becker-type dystrophy, NOS I and dystrophin complex components were absent or drastically reduced in the sarcolemma region. In other dystrophies, as well as in metabolic and inflammatory myopathies, NOS I and dystrophin complex constituents were expressed normally, while in the case of neurogenic diseases leading to denervation atrophy and especially congenital idiopathic clubfoot, the immunohistochemical patterns of the distribution of the dystrophin complex constituents were normal, but NOS I activity and protein were deficient or dramatically diminished. The results can be interpreted as indicating that, in general, NOS I targeting to the sarcolemma is dependent on particular members of the dystrophin complex, such as alpha-1 syntrophin, yet the expression and/or positioning of NOS I may be under the control of further factors, probably of neurogenic origin. NOS I-associated diaphorase may thus be a useful complementary tool in the diagnosis of muscle disorders.
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PMID:Absence of nitric oxide synthase I despite the presence of the dystrophin complex in human striated muscle. 914 66

To substantiate the role of nitric oxide synthase type-I (NOS-I) in neurogenic muscular disorders we investigated human biopsy samples of type-II fiber atrophy and amyotrophic lateral sclerosis (ALS) by NOS-I immunoreactivity (-IR), NOS-associated NADPH-dependent diaphorase activity (NOSaD) and Western blot analysis. In type-II atrophy, loss of NOSaD and reduced NOS-I-IR was apparent in atrophic myofibers. In atrophic fiber groups lacking NOSaD, both NOS-I and dystrophin-IR was decreased while sarcolemmal beta-dystroglycan- and adhalin-IR (markers of the sarcolemmal dystrophin-glycoprotein complex) was normal. In ALS, groups of scattered angulated atrophic fibers revealed partial loss of NOS-I-IR/NOSaD. Atrophied fibers of either type-I or type-II thus revealed differential sarcolemmal NOS/NOSaD pattern thereby reflecting myopathological alterations of the NO-system in human type-II atrophy and ALS.
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PMID:Partial loss of NADPH-diaphorase/nitric oxide synthase-complex in amyotrophic lateral sclerosis and human type-II myofiber atrophy. 930 Jun 47

Nitric oxide synthase I (NOS I) has been localized to the skeletal muscle sarcolemma in a variety of vertebrate species including man. It is particularly enriched at neuromuscular junctions. Recently, the N-methyl-D-aspartate (NMDA) receptor subunit 1 (NMDAR-1) has been detected in the postjunctional sarcolemma of rat diaphragm, providing a clue as to the possible source of Ca2+ ions that are necessary for NOS I activation. To address this possibility, we studied the distribution of NMDAR-1 and NOS I in mouse and rat skeletal muscles by immunohistochemistry and enzyme histochemistry. NMDAR-1 and NOS I were closely associated at neuromuscular junctions primarily of type II muscle fibers. NOS I was also present in the extrajunctional sarcolemma of this fiber type. Dystrophin, beta-dystroglycan, alpha-sarcoglycan, and spectrin were found normally expressed in both the junctional and extrajunctional sarcolemma of both fiber types. By contrast, in the muscle sarcolemma of MDX mice, dystrophin and dystrophin-associated proteins were reduced or absent. NOS I immunoreactivity was lost from the extrajunctional sarcolemma and barely detectable in the junctional sarcolemma. NOS I activity was clearly demonstrable in the junctional sarcolemma by NADPH diaphorase histochemistry, especially when the two-step method was used. NMDAR-1 was not altered. These data suggest that different mechanisms act to attach NOS I to the junctional versus extrajunctional sarcolemma. It may further be postulated that NMDA receptors are involved not only in the regulation but also sarcolemmal targeting of NOS I at neuromuscular junctions of type II fibers. The evidence that glutamate may function as a messenger molecule at vertebrate neuromuscular junction is discussed.
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PMID:Co-localization of nitric oxide synthase I (NOS I) and NMDA receptor subunit 1 (NMDAR-1) at the neuromuscular junction in rat and mouse skeletal muscle. 939 43

As intrafusal nuclear bag and chain fibers of muscle spindles take part in both sensory and motor functions, these stretch receptors may represent a useful model to answer the question whether nitric oxide (NO) signalling is involved in sensory and motor functions or motor events only, as has already been shown for ordinary extrafusal fibers. To answer these questions, we have applied immunohistochemical and enzyme histochemical methods to serial transverse sections of the rat gastrosoleus muscle for determining the presence or absence of NOS I, NOS-associated diaphorase (NOSaD), AChE and proteins related to the dystrophin complex. NOS I, NOSaD, and AChE were practically absent from the equatorial (central) region of intrafusal fibers, i.e. the site of termination of the primary and secondary afferents. These regions showed weak staining for dystrophin, beta-dystroglycan as well as alpha- and gamma-sarcoglycan. By contrast, all of these molecules were found enriched in the polar (peripheral) regions of the intrafusal fiber sarcolemma. NOS I, NOSaD, dystrophin, beta-dystroglycan and the two sarcoglycans showed a general presence in the sarcolemma, whereas AChE was limited to the endplate region and other circumscribed areas. From these observations we would like to conclude that NO does not appear to be significantly or even not involved in signal transfer to the sensory nerve endings in the intrafusal fibers.
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PMID:NO is not substantially involved in afferent signalling in rat muscle spindles. 942 3

The neuronal isoform of nitric oxide synthase (nNOS, termed also NOS-I) is expressed in normal adult skeletal muscle, suggesting important functions for NO in muscle biology. However, the expression and subcellular localization of NOS in muscle development and myoblast differentiation are largely unknown. In the present study, NOS was immunolocalized with isoform-specific antibodies in developing muscle and in differentiated myoblast cultures (mouse C2C12) together with histochemical NADPH-dependent diaphorase activity that is blocked by specific NOS inhibitors and therefore designated as NOS-associated diaphorase activity (NOSaD). Western blot analysis revealed immunoreactive bands for NOS-I-III in lysates from perinatal and adult muscle tissue and C2C12-myotubes that comigrated with prototypical proteins. In embryonic skeletal muscle, but not in adult myofibers, diffuse cytosolic staining and lack of sarcolemmal NOSaD activity and NOS-I immunoreaction were evident. In both myoblasts and fusioned myotubes, NOSaD and NOS isoforms I-III colocalize in the cytosol. Additionally, members of the sarcolemmal dystrophin-glycoprotein complex (i.e., dystrophin, adhalin, beta1-dystroglycan) immunolocalize in the cytosol of differentiating myoblasts, whereas anti-dystrophin and anti-beta1-dystroglycan clearly delineate the sarcolemma in myotubes. Thus, expression of NOS isoforms I-III and NOSaD is cytosolic in fusion-competent myoblasts during myotube formation in vitro. Interaction of NOSaD/NOS-I with the sarcolemmal dystrophin-complex known from mature myofibers is apparently lacking in prenatal muscle development and differentiating myoblasts. Localization of NOS isoforms thus characterized in myogenic cultures may help further to investigate regulated NO formation in muscle cells in vitro.
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PMID:Nitric oxide synthase (NOS) in mouse skeletal muscle development and differentiated myoblasts. 956 Apr 72

Previously, we and others have reported association of nitric oxide (NO)-generating nitric oxide synthase I (NOS I) with dystrophin in the subsarcolemmal cytoskeleton of striated muscle fibers. Since this structure shows a costameric organization the detailed distribution of NOS I and other molecules inside and outside the subsarcolemmal cytoskeleton was investigated. Using catalytic histochemistry and immunohistochemistry on rat skeletal muscle NOS I was colocalized in the costameres together with dystrophin, beta-dystroglycan, alpha-, beta- and gamma-sarcoglycan, beta 1-integrin, vinculin, paxillin and caveolin-3. Additionally, only NOS appeared in uncharacterized subsarcolemmal wave-like structures. These data show 1) a growing family of proteins assembled in the costameres including NOS I as described here for the first time, 2) expanded distribution patterns for NOS I, and 3) therefore, presumably uneven NO concentrations within the skeletal muscle fibers which may have implications for NO function.
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PMID:Nitric oxide synthase I (NOS I) is a costameric enzyme in rat skeletal muscle. 984 23

Duchenne muscular dystrophy is a devastating neuromuscular disease caused by lack of the protein, dystrophin, in skeletal muscle and heart, although the biochemical mechanism by which dystrophin loss causes muscle dysfunction is unknown. Here we show that the dystrophin-deficient mdx mouse and a mouse lacking both dystrophin and the dystrophin-related protein, utrophin (dko), have abnormal electrocardiograms (ECGs). In skeletal muscle, dystrophin is normally associated with neuronal nitric oxide synthase (nNOS) at the sarcolemma. Consequently, we have measured NOS isoform activities in hearts from control, mdx and dko mice. In control mouse hearts, eNOS and nNOS activities increased by 120% and 47%, respectively, between 2 and 6 months of age. In mdx mice, myocardial nNOS activity was decreased by 60%, 84% and 80% at 2, 6 and 12 months of age, respectively. Similarly, hearts from dko mice showed a 65% decrease in nNOS activity compared to controls at 2 months of age. Endothelial NOS (eNOS) activity was not affected by dystrophin loss, but inducible NOS (iNOS) activity was seven-fold higher than control in the mdx mouse heart by 12 months of age. We conclude that lack of dystrophin in the mdx mouse results in abnormal ECGs that are associated with decreased myocardial nNOS and increased iNOS activities.
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PMID:Decreased myocardial nNOS, increased iNOS and abnormal ECGs in mouse models of Duchenne muscular dystrophy. 1052 23


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