K+ channel openers suppress myotonic activity of human skeletal muscle in vitro |
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Authors: | S Quasthoff A Spuler W Spittelmeister F Lehmann-Horn P Grafe |
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Affiliation: | Physiologisches Institut, Universit?t München, F.R.G. |
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Abstract: | Isolated fibre bundles from myotonic human skeletal muscle showed after-contractions and spontaneous mechanical activity. The K+ channel openers cromakalim (10-100 mumols/l) and EMD 52962 (1-10 mumols/l) completely suppressed these abnormalities in mechanical activity. Voltage-clamp experiments revealed that cromakalim (100 mumols/l) increased the membrane K+ conductance of isolated, non-myotonic human skeletal muscle fibres 4-fold; Cl- conductance was not altered. The data show that myotonia is suppressed by an increase in in membrane K+ conductance. |
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