Issues & Opinions
Nav1.4 slow-inactivation: Is it a player in the warm-up phenomenon of myotonic disorders?
Article first published online: 4 FEB 2013
Copyright © 2012 Wiley Periodicals, Inc.
Muscle & Nerve
Volume 47, Issue 4, pages 483–487, April 2013
How to Cite
Lossin, C. (2013), Nav1.4 slow-inactivation: Is it a player in the warm-up phenomenon of myotonic disorders?. Muscle Nerve, 47: 483–487. doi: 10.1002/mus.23713
- Issue published online: 25 MAR 2013
- Article first published online: 4 FEB 2013
- Accepted manuscript online: 7 NOV 2012 04:54AM EST
- Manuscript Accepted: 25 OCT 2012
- myotonia congenita;
- warm-up phenomenon;
- sodium-channel slow-inactivation
Myotonia is a heritable disorder in which patients are unable to willfully relax their muscles. The physiological basis for myotonia lies in well-established deficiencies of skeletal muscle chloride and sodium conductances. What is unclear is how normal muscle function can temporarily return with repeated movement, the so-called “warm-up” phenomenon. Electrophysiological analyses of the skeletal muscle voltage-gated sodium channel Nav1.4 (gene name SCN4A), a key player in myotonia, have revealed several parallels between the Nav1.4 biophysical signature, specifically slow-inactivation, and myotonic warm-up, which suggest that Nav1.4 is critical not only in producing the myotonic reaction, but also in mediating the warm-up. Muscle Nerve, 2013