Tan, SV;
Z'Graggen, WJ;
Hanna, MG;
Bostock, H;
(2017)
In vivo assessment of muscle membrane properties in the sodium channel myotonias.
Muscle & Nerve
, 57
(4)
pp. 586-594.
10.1002/mus.25956.
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Abstract
INTRODUCTION: The gain-of-function mutations that underlie sodium channel myotonia(SCM) and paramyotonia congenita(PMC) produce differing clinical phenotypes. We used muscle velocity recovery cycles (MVRCs) to investigate membrane properties. METHODS: MVRCs and responses to trains of stimuli were compared in patients with SCM (n=9), PMC (N=8), and normal controls (n=26). RESULTS: The muscle relative refractory period was reduced in SCM, consistent with faster recovery of the mutant sodium channels from inactivation. Both SCM and PMC showed an increased early supernormality, and increased mean supernormality following multiple conditioning stimuli, consistent with slowed sodium channel inactivation. Trains of fast impulses caused a loss of amplitude in PMC, after which only half of the muscle fibres recovered, suggesting that the remainder stayed depolarized by persistent sodium currents. DISCUSSION: The differing effects of mutations on sodium channel function can be demonstrated in human subjects in vivo using this technique.
| Type: | Article |
|---|---|
| Title: | In vivo assessment of muscle membrane properties in the sodium channel myotonias |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/mus.25956 |
| Publisher version: | http://doi.org/10.1002/mus.25956 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Sodium channel; Myotonia; Paramyotonia congenita; Membrane potential; Velocity recovery cycle; channelopathy |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > UCL Queen Square Institute of Neurology > Department of Neuromuscular Diseases |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1573192 |
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