Regulation of the cross-bridge transition from a weakly to strongly bound state in skinned rabbit muscle fibers.
Regulation of the cross-bridge transition from a weakly to strongly bound state in skinned rabbit muscle fibers.
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去皮兔肌纤维中从弱结合状态到强结合状态的跨桥转变的调节。
DOI：
10.1152/ajpcell.1995.269.6.c1532
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Homsher,E
中科院分区：
文献类型：
--
作者：
Regnier,M;Morris,C;Homsher,E
在10 ℃下，通过测量快速释放-再拉伸循环（ktr）后的力发展速率、从笼状Pi光生Pi后的力下降速率（kPi）以及在存在和不存在强跨桥形成抑制剂的情况下的刚度，在带皮肌纤维中研究了从弱附着到受力状态的跨桥转变的调节。3-丁二酮单肟（BDM）。BDM和Pi都抑制了力而不是刚度。然而，减少钙离子抑制力和刚度在一个平行的方式。在3 mM BDM中，ktr和kPi均可逆性降低（降低30-35%），但两者均随Pi浓度增加而增加。降低Ca 2+浓度以匹配在3 mM BDM中观察到的力对kPi没有影响，但使ktr降低85%。这些结果是不一致的跨桥模型经历的过渡从弱约束力产生的状态在一个单一的步骤，但有两个步骤，其中之一是由pCa控制的模型是一致的。
The regulation of cross-bridge transition from weakly attached to force-bearing states was studied at 10 degrees C in skinned muscle fibers by measuring the rate of force development after a quick release-restretch cycle (ktr), the rate of force decline (kPi) after photogeneration of Pi from caged Pi, and stiffness in the presence and absence of an inhibitor of strong cross-bridge formation, 2,3-butanedione monoxime (BDM). Both BDM and Pi suppressed force more than stiffness. However, reduction of Ca2+ suppressed force and stiffness in a parallel fashion. Both ktr and kPi were reversibly reduced (by 30-35%) in 3 mM BDM, but both were increased by increasing Pi concentration. Reduction of Ca2+ concentration to match the force seen in 3 mM BDM had no effect on kPi but decreased ktr by 85%. These results are inconsistent with cross-bridge models undergoing the transition from a weakly bound to a force-generating state in a single step but are consistent with a model having two steps, one of which is controlled by pCa.