THE FORCE-VELOCITY RELATION OF THE RABBIT INFERIOR OBLIQUE MUSCLE INFLUENCE OF TEMPERATURE
THE FORCE-VELOCITY RELATION OF THE RABBIT INFERIOR OBLIQUE MUSCLE INFLUENCE OF TEMPERATURE
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DOI：
10.1007/bf00378532
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发表时间：
1994-04-01
影响因子：
4.5
通讯作者：
MARECHAL, G
中科院分区：
文献类型：
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作者：
ASMUSSEN, G;BECKERSBLEUKX, G;MARECHAL, G
在20~35℃温度范围内，用直接刺激的方法研究了兔下斜肌(IO)的收缩特性，并用等速释放来确定力/速度关系。将肌肉从35℃降温到20℃，温度系数(Q(10))为0.4的单次抽动的收缩和半松弛时间增加，但对抽动张力没有显著影响。强直性张力随温度升高而增大(Q(10)=1.32)。冷却使IO的最大缩短速度降低，Q(10)为1.6，最大机械功率降低，Q(10)为2.3。在35℃时，肌肉的最大缩短速度(19+/-2肌长/S，平均+/-扫描电子显微镜)对应于肌节的最大缩短速度为57+/-6微米/S。这一值与较小啮齿动物(小鼠和大鼠)眼外肌的数据相似。与哺乳动物四肢肌肉相比，哺乳动物EOM的等长和力-速度特性似乎与动物的大小几乎无关。因此，IO是一种快抽动肌肉，其最大缩短速度高于快抽动骨骼肌，但使用的强直性机械功率低于慢抽动肌肉：这些特性的结合使其非常适合于高速移动低质量的眼球。
The contractile properties of the rabbit inferior oblique muscle (IO) were studied in vitro with direct stimulation at temperatures between 20 and 35 degrees C. Isovelocity releases were used to determine the force/ velocity relation. Cooling the muscle from 35 degrees C to 20 degrees C increased contraction and half-relaxation times of single twitches with a temperature coefficient (Q(10)) of 0.4, but did not affect significantly the twitch tension. The tetanic tension increases with increasing temperature (Q(10) = 1.32). Cooling decreased the maximum shortening velocity of the IO with a Q(10) of 1.6 and the maximum mechanical power with a Q(10) of 2.3. At 35 degrees C, the maximum speed of shortening of the muscle (19 +/- 2 muscle lengths/s, mean+/-SEM) corresponded to a maximum shortening velocity of the sarcomeres of 57 +/- 6 mu m/s. This value is similar to data obtained for extraocular muscles (EOM) of smaller rodents (mice and rats). In comparison with mammalian limb muscles the isometric and force-velocity properties of mammalian EOM appear to be virtually independent of the size of the animal. Thus, IO is a fast-twitch muscle endowed with a maximum velocity of shortening higher than that of fast-twitch skeletal muscle, but using a tetanic mechanical power lower than that produced by slow-twitch muscle: the combination of these properties makes it ideally suited to move an ocular globe of low mass at high velocity.