Jayne B C, Lauder G V
Department of Biological Sciences, University of Cincinnati, OH 45221-0006.
J Comp Physiol A. 1994 Jul;175(1):123-31. doi: 10.1007/BF00217443.
We quantified the intensity and duration of electromyograms (emgs) from the red and white axial muscles in five bluegill sunfish (Lepomis macrochirus) which performed three categories of behavior including steady swimming and burst and glide swimming at moderate and rapid speeds. Steady swimming (at 2 lengths/s) involved exclusively red muscle activity (mean posterior emg duration = 95 ms), whereas unsteady swimming utilized red and white fibers with two features of fiber type recruitment previously undescribed for any ectothermic vertebrate locomotor muscle. First, for moderate speed swimming, the timing of red and white activity differed significantly with the average onset time of white lagging behind that of red by approximately 40 ms. The durations of these white emgs were shorter than those of the red emgs (posterior mean = 82 ms) because offset times were effectively synchronous. Second, compared to steady and moderate speed unsteady swimming, the intensity of red activity during rapid unsteady swimming decreased while the intensity of white muscle activity (mean white emg duration = 33 ms) increased. Decreased red activity associated with increased white activity differs from the general pattern of vertebrate muscle recruitment in which faster fiber types are recruited in addition to, but not to the exclusion of, slower fiber types.
我们对五条蓝鳃太阳鱼（Lepomis macrochirus）红色和白色轴肌的肌电图（emg）强度和持续时间进行了量化，这些鱼进行了三类行为，包括以中等和快速速度进行稳定游泳、爆发式游泳和滑行游泳。稳定游泳（速度为2体长/秒）仅涉及红色肌肉活动（平均后部肌电图持续时间 = 95毫秒），而不稳定游泳则利用红色和白色纤维，具有两种纤维类型募集特征，这是此前任何变温脊椎动物运动肌肉都未描述过的。首先，对于中等速度游泳，红色和白色活动的时间存在显著差异，白色活动的平均起始时间比红色落后约40毫秒。这些白色肌电图的持续时间比红色肌电图短（后部平均值 = 82毫秒），因为结束时间实际上是同步的。其次，与稳定和中等速度的不稳定游泳相比，快速不稳定游泳期间红色活动强度降低，而白色肌肉活动强度（平均白色肌电图持续时间 = 33毫秒）增加。红色活动减少与白色活动增加不同于脊椎动物肌肉募集的一般模式，在该模式中，除了较慢纤维类型外还会募集较快纤维类型，但不会排除较慢纤维类型。
