Stretch-induced activation of Ca(2+)-activated K(+) channels in mouse skeletal muscle fibers.
High-conductance Ca(2+)-activated K(+) (K(Ca)) channels were studied in mouse skeletal muscle fibers using the patch-clamp technique. In inside-out patches, application of negative pressure to the patch induced a dose-dependent and reversible activation of K(Ca) channels. Stretch-induced increase in channel activity was found to be of the same magnitude in the presence and in the absence of Ca(2+) in the pipette. The dose-response relationships between K(Ca) channel activity and intracellular Ca(2+) and between K(Ca) channel activity and membrane potential revealed that voltage and Ca(2+) sensitivity were not altered by membrane stretch. In cell-attached patches, in the presence of high external Ca(2+) concentration, stretch-induced activation was also observed. We conclude that membrane stretch is a potential mode of regulation of skeletal muscle K(Ca) channel activity and could be involved in the regulation of muscle excitability during contraction-relaxation cycles.
Mallouk
N
N
Laboratoire de Physiologie des Eléments Excitables, Unité Mixte de Recherche, Centre National de la Recherche Scientifique 5578, Université C. Bernard Lyon I, 69622 Villeurbanne Cedex, France.
Allard
B
B
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*
D015221:Potassium Channels; D000255:Adenosine Triphosphate; D002118:Calcium