Abstract
In rats treated with high-dose corticosteroids, skeletal muscle that is denervated in vivo (steroid-denervated) develops electrical inexcitability similar to that seen in patients with acute quadriplegic myopathy. To determine whether changes in muscle gene transcription might underlie inexcitability of steroid-denervated muscle we performed RNase protection assays to quantitate adult (SkM1) and embryonic (SkM2) sodium channel isoforms and chloride channel (CLC-1) mRNA levels in control, denervated, steroid-innervated, and steroid-denervated skeletal muscle. While SkM1 mRNA levels were relatively unaffected by denervation or steroid treatment, SkM2 mRNA levels were increased by both. These effects were synergistic and high levels of SkM2 mRNA were expressed in denervated muscle exposed to corticosteroids. Skeletal muscle CLC-1 mRNA levels were decreased by denervation. To better understand the marked upregulation of SkM2 in steroid-denervated muscle we examined changes in myogenin and glucocorticoid receptor mRNA levels. However, changes in these mRNA levels cannot account for the upregulation of SkM2 in steroid-denervated muscle.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.