Relaxation kinetics following sudden Ca(2+) reduction in single myofibrils from skeletal muscle.
Relaxation kinetics following sudden Ca(2+) reduction in single myofibrils from skeletal muscle.
复制标题
骨骼肌单个肌原纤维中 Ca(2) 突然减少后的松弛动力学。
DOI：
10.1016/s0006-3495(02)73974-x
复制
发表时间：
2002
影响因子：
3.4
通讯作者：
C. Poggesi
中科院分区：
文献类型：
--
作者：
C. Tesi;N. Piroddi;F. Colomo;C. Poggesi
为了研究跨桥解离和跨桥诱导的细丝激活在肌肉松弛时程中的作用，我们通过快速（约10 ms）从高到低[Ca 2 +]溶液切换来启动骨骼肌单肌原纤维的力松弛。从最大激活的全力衰减发生在两个阶段：一个缓慢的，然后是一个快速的。后者由肌节“给予”启动并由肌节间动力学支配（参见配套论文，Stehle，R.，M. Krueger和G.辉瑞制药2002.Biophys.J.83：2152-2161），而前者发生在近似等轴条件下，并且对机械扰动敏感。在放松开始之前降低Ca 2+激活力并不能增加缓慢等长相的速率，这表明产生循环力的跨桥在放松过程中并不能显著维持激活。这一结论得到加强的发现，等距松弛率从最大力到任何给定的Ca 2+激活力水平是类似的Ca 2+激活从休息到该给定的力。因此，在完全弛豫中，力衰减的缓慢速率很可能仅仅反映了跨桥离开力产生状态的速率。因为增加[Pi]加速松弛而增加[MgADP]减慢松弛，所以横桥从力产生状态到非力产生状态的向前和向后转变都有助于肌肉松弛。
To investigate the roles of cross-bridge dissociation and cross-bridge-induced thin filament activation in the time course of muscle relaxation, we initiated force relaxation in single myofibrils from skeletal muscles by rapidly (∼10ms) switching from high to low [Ca2+] solutions. Full force decay from maximal activation occurs in two phases: a slow one followed by a rapid one. The latter is initiated by sarcomere "give" and dominated by inter-sarcomere dynamics (see the companion paper, Stehle, R., M. Krueger, and G. Pfitzer. 2002.Biophys.J. 83:2152–2161), while the former occurs under nearly isometric conditions and is sensitive to mechanical perturbations. Decreasing the Ca2+-activated force preceding the start of relaxation does not increase the rate of the slow isometric phase, suggesting thatcyclingforce-generating cross-bridges do not significantly sustain activation during relaxation. This conclusion is strengthened by the finding that the rate of isometric relaxation from maximum force to any given Ca2+-activated force level is similar to that of Ca2+-activation from rest to that given force. It is likely, therefore, that the slow rate of force decay in full relaxation simply reflects the rate at which cross-bridges leave force-generating states. Because increasing [Pi] accelerates relaxation while increasing [MgADP] slows relaxation, both forward and backward transitions of cross-bridges from force-generating to non-force-generating states contribute to muscle relaxation.
登录
查看更多内容
去皮兔比目鱼肌纤维中力产生和磷酸盐释放的动力学。
DOI：
10.1152/ajpcell.1992.262.5.c1239
发表时间：
1992
期刊：
The American journal of physiology
影响因子：
--
作者：
Millar,NC;Homsher,E
通讯作者：
Homsher,E
线性松弛阶段斜坡缩短对完整骨骼肌纤维中 [Ca2]i 的影响。
DOI：
10.1152/ajpcell.1999.276.1.c152
发表时间：
1999
期刊：
The American journal of physiology
影响因子：
--
作者：
Jiang,Y;Julian,FJ
通讯作者：
Julian,FJ
Ca2 对骨骼肌磷酸盐释放动力学的影响。
DOI：
--
发表时间：
1992
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Walker,JW;Lu,Z;Moss,RL
通讯作者：
Moss,RL
钙和桥在确定青蛙肌肉纤维力量发展速率中的作用。
DOI：
10.1152/ajpcell.1997.272.5.c1664
发表时间：
1997
期刊：
The American journal of physiology
影响因子：
--
作者：
Wahr,PA;Rall,JA
通讯作者：
Rall,JA
磷酸盐和钙对甘油兔骨骼肌纤维产生力的影响。
DOI：
--
发表时间：
1990
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Millar,NC;Homsher,E
通讯作者：
Homsher,E