The dynamics of the nitric oxide release-transient from stretched muscle cells

Potent nitric oxide (NO) signals are described for many forms of cell-cell communication. Although NO plays a significant role in skeletal muscle metabolism and contractility and in precursor activation during muscle formation and stretching, there is no direct evidence of stretch-induced NO release from muscle. Differentiated muscle cell cultures from normal and dystrophic mdx mice were preloaded with the NO-specific dye DAF-2 (diaminofluorescein-2) before stretching. NO release was detected by video-microscopy. NO was released rapidly from wild-type (WT) cells after stretch and intensity declined rapidly to a plateau. Mdx cells showed much less NO release. Direct observations of the time-course of stretch-induced NO release in WT cells is congruent with the hypothesis of NO-mediated stretch activation of satellite cells in normal skeletal muscle. Distinct differences in the time-course between normal and dystrophic cells indicate visualization methods for NO release will be a sensitive measure of NOS-1 restoration following diverse treatment approaches to muscular dystrophy.