کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6041661 | 1189309 | 2013 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Extracellular magnesium and calcium reduce myotonia in ClC-1 inhibited rat muscle
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کلمات کلیدی
EDL9-ACExtracellular Ca2+ concentrationVRestNKR9-Anthracenecarboxylic acid - 9-آنتراسنکربوکیک اسیدAUC - AUC[Ca2+]o - [Ca2 +] oextensor digitorum longus - اکستانسور بلند شست انگشتانPhenotypic variation - تغییرات فنوتیپیMyotonia congenita - سندرم متابولیکarea under the curve - منطقه تحت منحنیresting membrane potential - پتانسیل غشای استراحتVth - پنجمExtracellular calcium - کلسیم خارج سلولی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علم عصب شناسی
علوم اعصاب تکاملی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Extracellular magnesium and calcium reduce myotonia in ClC-1 inhibited rat muscle Extracellular magnesium and calcium reduce myotonia in ClC-1 inhibited rat muscle](/preview/png/6041661.png)
چکیده انگلیسی
Loss-of-function mutations in the ClC-1 Clâ channel trigger skeletal muscle hyperexcitability in myotonia congenita. For reasons that remain unclear, the severity of the myotonic symptoms can vary markedly even among patients with identical ClC-1 mutations, and may become exacerbated during pregnancy and with diuretic treatment. Since both these conditions are associated with hypomagnesemia and hypocalcemia, we explored whether extracellular Mg2+ and Ca2+ ([Mg2+]o and [Ca2+]o) can affect myotonia. Experimental myotonia was induced in isolated rat muscles by ClC-1 inhibition and effects of [Mg2+]o or [Ca2+]o on myotonic contractions were determined. Both cations dampened myotonia within their physiological concentration ranges. Thus, myotonic contractile activity was 6-fold larger at 0.3 than at 1.2Â mM [Mg2+]o and 82-fold larger at 0.3 than at 1.27Â mM [Ca2+]o. In intracellular recordings of action potentials, the threshold for action potential excitation was raised by 4-6Â mV when [Mg2+]o was elevated from 0.6 to 3Â mM, compatible with an increase in the depolarization of the membrane potential necessary to activate the Na+ channels. Supporting this notion, mathematical simulations showed that myotonia went from appearing with normal Clâ channel function to disappearing in the absence of Clâ channel function when Na+ channel activation was depolarized by 6Â mV. In conclusion, variation in serum Mg2+ and Ca2+ may contribute to phenotypic variation in myotonia congenita patients.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Neuromuscular Disorders - Volume 23, Issue 6, June 2013, Pages 489-502
Journal: Neuromuscular Disorders - Volume 23, Issue 6, June 2013, Pages 489-502
نویسندگان
Martin Skov, Anders Riisager, James A. Fraser, Ole B. Nielsen, Thomas H. Pedersen,