来自昆虫纤维状肌肉的关于基本收缩过程的证据。
Evidence from insect fibrillar muscle about the elementary contractile process.
作者信息
Pringle J W
出版信息
J Gen Physiol. 1967 Jul;50(6):Suppl:139-56. doi: 10.1085/jgp.50.6.139.
Bundles of myofibrils prepared from the dorsal longitudinal flight muscles of giant water bugs show oscillatory contractile activity in solutions of low ionic strength containing ATP and 10(-8)-10(-7)M Ca(2+). This is due to delay between changes of length and changes of tension under activating conditions. The peculiarities of insect fibrillar muscle which give rise to this behavior are (1) the high elasticity of relaxed myofibrils, (2) a smaller degree of Ca(2+) activation of ATPase activity in unstretched myofibrils and extracted actomyosin, and (3) a direct effect of stretch on ATPase activity. It is shown that the cross-bridges of striated muscle are probably formed from the heads of three myosin molecules and that in insect fibrillar muscle the cycles of mechanochemical energy conversion in the cross-bridges can be synchronized by imposed changes of length. This material is more suitable than vertebrate striated muscle for a study of the nature of the elementary contractile process.
从大田鳖背纵飞行肌制备的肌原纤维束，在含有ATP和10⁻⁸ - 10⁻⁷M Ca²⁺的低离子强度溶液中表现出振荡收缩活性。这是由于在激活条件下长度变化和张力变化之间存在延迟。导致这种行为的昆虫纤维状肌肉的特性有：（1）松弛肌原纤维的高弹性；（2）未拉伸肌原纤维和提取的肌动球蛋白中Ca²⁺对ATP酶活性的激活程度较小；（3）拉伸对ATP酶活性的直接影响。结果表明，横纹肌的横桥可能由三个肌球蛋白分子的头部形成，并且在昆虫纤维状肌肉中，横桥中的机械化学能量转换循环可以通过施加的长度变化来同步。这种材料比脊椎动物横纹肌更适合用于研究基本收缩过程的本质。
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