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Properties of Ca 2+ ‐activated K + channels in erythrocytes from patients with myotonic muscular dystrophy
Author(s) -
Pellegrino Mario,
Pellegrini Monica,
Bigini Paolo,
Scimemi Annalisa
Publication year - 1998
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/(sici)1097-4598(199811)21:11<1465::aid-mus15>3.0.co;2-#
Subject(s) - myotonic dystrophy , patch clamp , chemistry , biophysics , calcium , intracellular , myotonia , conductance , muscular dystrophy , electrophysiology , medicine , biochemistry , biology , physics , organic chemistry , condensed matter physics
Using the single‐channel patch‐clamp technique, Ca 2+ ‐activated K + channels of erythrocytes from patients with myotonic muscular dystrophy (MyD) were studied. Elementary single‐channel properties—conductance, rectification, kinetics, voltage‐ and calcium‐dependence—measured in inside‐out patches of MyD erythrocytes, did not differ significantly from those of control cells. The activity of the channels, studied in patches attached to red cells from MyD patients, exhibited mean patch currents which were significantly higher than the controls. The increased mean patch current was due to a higher opening frequency, associated with a reduced mean channel closed time. These results indicate that Ca 2+ ‐activated K + channels of erythrocytes from patients either detect a higher intracellular calcium concentration and/or express an augmented calcium‐sensitivity. Since these channels are targets for phosphorylation, our findings make it possible to identify defective kinase mechanisms, in minimally disturbed cells of the patient, at a molecular level of resolution. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1465–1472, 1998