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Pflügers Archiv

, Volume 444, Issue 5, pp 634–643 | Cite as

Sarcoplasmic reticulum function in slow- and fast-twitch skeletal muscles from mdx mice

  • Alexandra Divet
  • Corinne Huchet-Cadiou
Original Article

Abstract.

The aim of the present study was to establish whether alterations in sarcoplasmic reticulum function are involved in the abnormal Ca2+ homeostasis of skeletal muscle in mice with muscular dystrophy (mdx). The properties of the sarcoplasmic reticulum and contractile proteins of fast- and slow-twitch muscles were therefore investigated in chemically skinned fibres isolated from the extensor digitorum longus (EDL) and soleus muscles of normal (C57BL/10) and mdx mice at 4 and 11 weeks of development. Sarcoplasmic reticulum Ca2+ uptake, estimated by the Ca2+ release following exposure to caffeine, was significantly slower in mdx mice, while the maximal Ca2+ quantity did not differ in either type of skeletal muscle at either stage of development. In 4-week-old mice spontaneous sarcoplasmic reticulum Ca2+ leakage was observed in EDL and soleus fibres and this was more pronounced in mdx mice. In addition, the maximal Ca2+-activated tension was smaller in mdx than in normal fibres, while the Ca2+ sensitivity of the contractile apparatus was not significantly different. These results indicate that mdx hindlimb muscles are affected differently by the disease process and suggest that a reduced ability of the Ca2+-ATPase to load Ca2+ and a leaky sarcoplasmic reticulum membrane may be involved in the altered intracellular Ca2+ homeostasis.

Sarcoplasmic reticulum Skeletal muscle Mdx mouse Skinned fibres Caffeine EDL Soleus 

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Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Alexandra Divet
    • 1
  • Corinne Huchet-Cadiou
    • 1
  1. 1.Laboratoire de Physiologie Générale, UMR CNRS 6018, Faculté des Sciences et des Techniques, Université de Nantes, 2 rue de la Houssinière, BP 92208, 44322 Nantes, Cedex 03, France

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