In vivo assessment of muscle membrane properties in the sodium channel myotonias.

Tan, S Veronica; Z'Graggen, Werner Josef; Hanna, Michael G; Bostock, Hugh (2018). In vivo assessment of muscle membrane properties in the sodium channel myotonias. Muscle & nerve, 57(4), pp. 586-594. John Wiley & Sons 10.1002/mus.25956

Text Tan_et_al-2017-Muscle_&_Nerve.pdf - Published Version Restricted to registered users only Available under License Publisher holds Copyright. Download (530kB) | Request a copy

INTRODUCTION

The gain-of-function mutations that underlie sodium channel myotonia (SCM) and paramyotonia congenital (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 fibers 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. Muscle Nerve, 2017.

Interest & Impact

Downloads

1 since deposited on 09 Jan 2018
0 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item