Cross-bridge-dependent changes in the intracellular Ca2+ concentration in mammalian cardiac muscles.
A change in muscle length significantly alters the developed tension in mammalian cardiac muscle compared to that in skeletal muscle fibers. The intracellular mechanisms related to the length-dependent change in developed tension have been studied using Ca2+ indicators in intact preparations; a cross-bridge-dependent change in the affinity of troponin-C for Ca2+ is a possible mechanism. This hypothesis is further supported by the measurement of Ca2+ bound to troponin-C in skinned preparations. The molecular mechanism of the cross-bridge-dependent change in the affinity of troponin-C for Ca2+ is not fully understood although the studies which employ the substitution of troponin-C in skinned preparations, transgenic animals and in an animal model with heart disease have been performed. We reviewed the current studies by analyzing the intracellular mechanism responsible for the length-dependent change in tension development in mammalian cardiac muscle.
Kurihara
S
S
Department of Physiology, Jikei University School of Medicine, Tokyo, Japan.
Komukai
K
K
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006801:Humans; D018485:Muscle Fibers, Skeletal / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D014336:Troponin / Q000378:metabolism; D019209:Troponin C
D014336:Troponin; D019209:Troponin C; D002118:Calcium