Extrajunctional resting Ca2+ influx is not increased in a severely dystrophic expiratory muscle (triangularis sterni) of the mdx mouse

C. George Carlson, Anton Gueorguiev, Diana M. Roshek, Rebecca Ashmore, Jacquelyne S. Chu, Judy E. Anderson

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

Freshly isolated adult mdx and nondystrophic (C57B110SnJ) muscle fibers were used to examine the potential role of resting Ca2+ influx in the pathogenesis of Duchenne and related dystrophies. Microfluorimetric determinations of resting divalent cation influx were obtained from undissociated intact muscle fibers in the triangularis sterni (TS), a thin expiratory muscle. Morphological evidence indicated severe dystrophic alterations in the mdx TS at 5 months, and a prononunced loss of fibers with connective tissue infiltration in older animals. To examine resting Ca 2+ influx, fibers were loaded with FURA PE3 and the rate of quenching of intracellular signal following the extracellular addition of Mn2+ was determined from extrajunctional regions. There was no significant difference in quench rate between nondystrophic and mdx TS fibers. These results indicate that severe dystrophic pathology in the absence of dystrophin is not due to generalized increases in resting Ca2+ influx.

Original languageEnglish
Pages (from-to)229-239
Number of pages11
JournalNeurobiology of Disease
Volume14
Issue number2
DOIs
StatePublished - Nov 2003

Keywords

  • Calcium
  • Calcium channels
  • Duchenne muscular dystrophy
  • Dystrophinopathies
  • Mdx mouse
  • Muscle necrosis

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