Calcium-independent activation of skinned cardiac muscle by secophalloidin.

  title={Calcium-independent activation of skinned cardiac muscle by secophalloidin.},
  author={Anna E. Bukatina and Lou J Theodore and Kenneth B. Campbell and Gary C. Sieck},
  journal={FEBS letters},
  volume={519 1-3},
Thin filament regulation of muscle contraction is believed to be mediated by both Ca2+ and strongly bound myosin cross-bridges. We found that secophalloidin (SPH, 5-8 mM) activates cross-bridge cycling without Ca2+ causing isometric force comparable to that induced by Ca2+. At saturated [SPH], Ca2+ further increased force by 20%. SPH-induced force was reversible upon washing with a relaxing solution. However, there was more than 30% irreversible loss in subsequent Ca2+-activated force. We… CONTINUE READING