Series elastic properties of skinned muscle fibres in contraction and rigor.
Isometric tension of skinned fibres from the frog semitendinosus muscle is sigmoidally related to Ca2+ concentration between pCa 7 and 6. Stiffness measurements showed that the Ca2+-activated tension may be due to recruitment of attached cross-bridges. In the absence of ATP (rigor solution) the skinned fibre develops a rigor tension which reaches about 80-110% of the maximum Ca2+-activated tension. However, stiffness measurements showed that in rigor many more cross-bridges are attached to actin at any one moment than in contraction. It was concluded that the force per cross-bridge is 37% smaller in rigor than in contraction.
D000199:Actins / Q000378:metabolism / Q000502:physiology; D000818:Animals; D001001:Anura; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D004548:Elasticity; D009119:Muscle Contraction; D009129:Muscle Tonus; D009132:Muscles / Q000378:metabolism / Q000502:physiology*; D011896:Rana temporaria
D000199:Actins; D002118:Calcium