Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20020 (adenosine triphosphatase)
 3,299 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rat muscle spindles contain one nuclear bag2, one nuclear bag1, and two nuclear chain fibers. The three different types of intrafusal fiber in spindles may be a reflection of concomitant changes in proportions of slow primary, slow/fast secondary, and fast secondary myotubes during the period of spindle development. We examined whether experimentally altering the available muscle substrates would impact the intrafusal fiber type composition of spindles. De novo formation of spindles in muscles devoid of primary myotubes was induced by crushing the nerve to the medial gastrocnemius muscle in newborn rats and administering nerve growth factor for ten days afterwards. Encapsulated fibers of the reinnervated muscles examined one month after nerve crush had myofibrillar adenosine triphosphatase and myosin heavy chain profiles similar to normal bag2, bag1, or chain intrafusal fibers. However, spindles in reinnervated muscles contained fewer fibers than controls. Most experimental spindles contained chain and/or bag1 fibers, the two fiber types which ordinarily arise during secondary myogenesis. In contrast, bag2 fibers, fibers that normally form concomitant with primary myogenesis, were absent from nearly 90% of spindles in reinnervated muscles. The paucity of bag2 fibers may reflect the absence of primary myotubes, whereas the prevalence of chain and/or bag1 fibers may reflect that secondary myotubes or myofibers that descended from the secondary myotubes were the principal muscle substrates available for spindle formation in the nerve-crushed muscles.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influence of muscle cell substrates on differentiation of intrafusal fiber types in neonatal rats. 845 Sep 72

The role of nerve growth factor (NGF) and its receptors in the physiology of skeletal muscles has not been extensively studied in animal models. We describe the production of transgenic lines of mice expressing a neutralizing antibody against NGF (alphaD11) and the morphological and histochemical analysis of skeletal muscles from adult and aged anti-NGF mice. This study reveals that the chronic deprivation of NGF results in a decreased size of myofibers of dorsal and hindlimb muscles in adult but not in postnatal day (P)2 mice. In myofibers from adult anti-NGF mice, the presence of central nuclei, vacuolization of the cytoplasm, and inflammatory cell infiltration was observed. The immunohistochemical analysis of these muscular fibers revealed an upregulation of p75 expression, a decrease in adenosine triphosphatase (ATP)ase activity, and a subsarcolemmal Congo Red-positive staining. Immunostaining with an antibody against amyloid precursor protein showed an increased labeling of the cytoplasm of myofibers from adult and aged anti-NGF mice. These features are reminiscent of human myopathies, such as inclusion body myositis. We conclude that NGF deficits might be relevant for a class of human myopathies.
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PMID:Muscular dystrophy in adult and aged anti-NGF transgenic mice resembles an inclusion body myopathy. 1067 95