Abstract | INTRODUCTION: Experimental myotonia induced in rat muscle by ClC-1 chloride channel-inhibited has been shown to be related inversely to extracellular concentrations of Mg(2+) and Ca(2+) ([Mg(2+) ]o and [Ca(2+) ]o) within physiological ranges. Because this implicates a role for [Mg(2+)]o and [Ca(2+)]o in the variability of symptoms among myotonia congenita patients, we searched for similar effects of [Mg(2+)]o and [Ca(2+)]o on myotonia in human muscle. METHODS: Bundles of muscle fibers were isolated from abdominal rectus in patients undergoing abdominal surgery. Myotonia was induced by ClC-1 inhibition using 9-anthracene carboxylic acid (9-AC) and was assessed from integrals of force induced by 5-Hz stimulation for 2 seconds. RESULTS:
Myotonia disappeared gradually when [Mg(2+)]o or [Ca(2+)]o were elevated throughout their physiological ranges. These effects of [Mg(2+)]o and [Ca(2+)]o were additive and interchangeable. CONCLUSIONS: These findings suggest that variations in symptoms in myotonia congenita patients may arise from physiological variations in serum Mg(2+) and Ca(2+).
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Authors | Martin Skov, Frank Vincenzo De Paoli, Jesper Lausten, Ole Baekgaard Nielsen, Thomas Holm Pedersen |
Journal | Muscle & nerve
(Muscle Nerve)
Vol. 51
Issue 1
Pg. 65-71
(Jan 2015)
ISSN: 1097-4598 [Electronic] United States |
PMID | 24710922
(Publication Type: Journal Article)
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Copyright | © 2014 Wiley Periodicals, Inc. |
Chemical References |
- Anthracenes
- CLC-1 channel
- Chloride Channels
- 9-anthroic acid
- Magnesium
- Calcium
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Topics |
- Adult
- Aged
- Aged, 80 and over
- Anthracenes
(pharmacology)
- Area Under Curve
- Biophysics
- Calcium
(pharmacology)
- Chloride Channels
(antagonists & inhibitors, metabolism)
- Dose-Response Relationship, Drug
- Electric Stimulation
- Female
- Humans
- In Vitro Techniques
- Magnesium
(pharmacology)
- Male
- Middle Aged
- Muscle Contraction
(drug effects)
- Muscle Fibers, Skeletal
(drug effects, pathology)
- Myotonia
(chemically induced)
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