Contractile properties of skinned muscle fibres from young and adult normal and dystrophic (mdx) mice.

Abstract

1. Single muscle fibres were enzymatically isolated from the soleus and extensor digitorum longus (EDL) muscles of genetically dystrophic mdx and normal (C57BL/10) mice aged 3‐6 or 17‐23 weeks. 2. Fibres of both muscles were chemically skinned with the non‐ionic detergent Triton X‐100 (2% v/v). Ca(2+)‐ and Sr(2+)‐activated contractile responses were recorded and comparisons were made between several contractile parameters of various fibre types of normal and dystrophic mice of similar age. 3. There were no significant differences in the following contractile parameters of skinned fibres of normal and mdx mice of the same age: sensitivity to activating Ca2+ (pCa50) or Sr2+ (pSr50) and differe..