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Possible role of apamin‐sensitive K + channels in myotonic dystrophy
Author(s) -
Behrens María Isabel,
Jalil Patricio,
Serani Alejandro,
Vergara Fernando,
Alvarez Osvaldo
Publication year - 1994
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880171104
Subject(s) - apamin , myotonia , myotonic dystrophy , myotonia congenita , medicine , endocrinology , chemistry , skeletal muscle , potassium channel
Myotonic muscular dystrophy is a genetic disease characterized mainly by muscle atrophy and myotonia, a repetitive electrical activity of muscle. In the present study, the possible role of apamin‐sensitive K + channels in the genesis of myotonia was investigated. Apamin is a peptide from bee venom that specifically blocks small conductance Ca 2+ ‐activated K + channels. The injection of a small amount of apamin (20–30 μl, 10 μmol/L) into the thenar muscle of myotonic dystrophy patients decreased the basal electrical activity during the electromyogram in the 6 patients studied. Myotonic discharges after muscle percussion were more difficult to trigger and of smaller intensity and duration. In 2 controls and in 2 patients with generalized myotonia, as well as in 1 patient with myotonia congenita (where the defect is in chloride channels), apamin had no effect. These results suggest that apamin‐sensitive K + channels participate in the mechanism that generates myotonia in myotonic dystrophy. © 1994 John Wiley & Sons, Inc.