title: Potassium channel activity in sarcolemmal vesicles formed from skeletal muscle fibres of normal and dystrophic mice.
abstract: Sarcolemmal vesicles were produced from adult mouse extensor digitorum longus muscle (EDL) by treating swollen muscle fibres with collagenase. Vesicles formed from dystrophic (C57BL/6J dy/dy) and phenotypically normal animals were patch clamped and the single channel activity was recorded. Three types of K+ channel were observed in excised patches taken from normal and dystrophic muscle. A large conductance (300 pS) Ca2(+)-dependent K+ channel (KCa) was the most frequently observed of the K+ channels in both types of muscle preparation. In a number of patches taken from dystrophic muscle the open probability-voltage relationship for the KCa channel was markedly different from that in normal muscle, suggesting a possible reduction in Ca2+ sensitivity. An ATP-sensitive K+ channel (90 pS) was common to both normal and dystrophic muscle vesicles and was present in a large number of patches. An inwardly rectifying K+ channel (40 pS) was also observed in both types of sarcolemmal vesicles. The properties of all three K+ channels types were broadly consistent with other observations of skeletal muscle K+ channels, though all had higher conductances than had previously been noted in other species.
authors.affiliation: Department of Physiological Sciences, University of Manchester, U.K.
authors.forename: I C
authors.initials: IC
authors.lastname: Rowe
authors.forename: A C
authors.initials: AC
authors.lastname: Wareham
authors.forename: M A
authors.initials: MA
authors.lastname: Whittle
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004553:Electric Conductivity; D051379:Mice; D009132:Muscles / Q000378:metabolism*; D009137:Muscular Dystrophy, Animal / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism* / Q000502:physiology; D012016:Reference Values; D012508:Sarcolemma / Q000378:metabolism*
chemical_list: D015221:Potassium Channels; D000255:Adenosine Triphosphate; D002118:Calcium