Time-resolved X-ray diffraction from frog skeletal muscle during shortening against an inertial load and a quick release.
Time-resolved X-ray diffraction from frog skeletal muscle during shortening against an inertial load and a quick release.
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青蛙骨骼肌在惯性负载缩短和快速释放过程中的时间分辨 X 射线衍射。
DOI：
10.2183/pjab.56.235
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
H. Sugi
中科院分区：
文献类型：
--
作者：
Y. Amemiya;T. Tameyasu;Hidehiro Tanaka;H. Hashizume;H. Sugi
脊椎动物骨骼肌中的赤道X射线衍射图案来自于粗细细丝的双六边形阵列。当肌肉等距收缩时，1，0赤道反射（I1，o）的强度减小，而1，1反射（I1，1）的强度增加，每个增加2倍。1 ~-4~这被解释为是由于横桥从粗细丝附近向细细丝的径向移动。2 ~，虽然最近对等长收缩和等长收缩的肌肉进行了时间分辨的X射线衍射研究，以提供关于横桥的动力学特性的信息，但还没有在力和肌肉长度都随时间变化的条件下进行实验。本文研究了青蛙骨骼肌在惯性负荷下缩短和快速释放过程中的时间分辨X射线衍射。所有的实验都是用牛蛙的缝匠肌进行的。将肌肉垂直安装在具有两个Mylar窗口和多电极组件的实验室中;将骨盆端夹在室中或连接到应变仪上以记录等长力，同时将胫骨端连接到具有两个等长臂（7 cm）的杠杆上，用感测杠杆角度的差动Transformer记录肌肉长度的变化。通过He-Ne激光的衍射图案将初始肌节长度调节至2.2-2.4 μ m。用充氧林格溶液（2-4°C）连续地对肌肉进行穿孔，并且通过以超过10秒的间隔施加持续时间为2毫秒的超大电流脉冲来产生抽搐。用位置传感器记录抽搐过程中的低角赤道X射线衍射图（样品到焦点的距离，36 mm）。
The equatorial X-ray diffraction pattern in vertebrate skeletall muscle arises from the double hexagonal array of the thick and thin filaments. When a muscle contracts isometrically, the intensity of 1,0 equatorial reflection (I1,o) decreases while that of 1,1 reflection (I1,1) increases, each by a factor of two.1~-4~ This has been interpreted as being due to the radial movement of the cross-bridges from the vicinity of the thick filaments towards the thin filaments.2~,4~ Although the time-resolved X-ray diffraction studies have recently been performedd on isometrically and isotonically contracting muscles to give information about the kinetic properties of the cross-bridges~-8 ~ no experiments have been performed in conditions in which both the force and the muscle length change with time. The present paper deals with the time-resolved X-ray diffraction of frog skeletal muscle during shortening against an inertial load and a quick release. All experiments were made with the sartorius muscles of the bullfrog Rana catesbeiana. The muscle was mounted vertically in an experimental chamber with two Mylar windows and a multi-electrode assembly; the pelvic end was clamped to the chamber or attached to a strain gauge to record isometric force, while the tibial end was connected to an alminium lever with two arms of equal length (7 cm), the change in muscle length being recorded with a differential transformer sensing the lever angle. The initial sarcomere length was adjusted to 2.2-2.4 pm by the diffraction pattern of He-Ne laser light. The muscle was continuously perf used with oxygenated Ringer solution (2-4°C), and twitches were produced by applying supramaximal current pulses of 2 msec duration at intervals of more than 10 sec. The low angle equatorial X-ray diffraction pattern (specimen to focus distance, 36 mm) during twitches were recorded with a position sensi-