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Altered gating and conductance of Na+channels in hyperkalemic periodic paralysis

✍ Scribed by F. Lehmann -Horn; P. A. Iaizzo; H. Hatt; Ch. Franke

Book ID
104744967
Publisher
Springer
Year
1991
Tongue
English
Weight
319 KB
Volume
418
Category
Article
ISSN
0031-6768

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✦ Synopsis

Electrophysiological studies on muscle fibres from patients with hyperkalemic periodic paralysis with myotonia have shown that the episodes of weakness are caused by a sustained depolarization of the sarcolemma to potentials between -40 and -60 mV. In muscle fibre segments from three such patients this sustained depolarization was caused by noninactivating Na+ channels with reduced single-channel conductance blocked by TTX and procainamide. As the chloride conductance was normal, myotonia may be best explained with the abnormal reopenings of the Na+ channels. The recently described genetic linkage between hyperkalemic periodic paralysis with myotonia and the gene coding for the TTX-sensitive Na+ channel suggests an altered primary structure of this channel causing its abnormal function.

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