Speed-dependent intrinsic caudal fin muscle recruitment during steady swimming in bluegill sunfish, Lepomis macrochirus
Speed-dependent intrinsic caudal fin muscle recruitment during steady swimming in bluegill sunfish, Lepomis macrochirus
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DOI：
10.1242/jeb.012096
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发表时间：
2008-02-15
影响因子：
2.8
通讯作者：
Lauder, George V.
中科院分区：
文献类型：
--
作者：
Flammang, Brooke E.;Lauder, George V.
在大多数硬骨鱼中，大约有50块肌肉控制着尾鳍的形状，尽管肌层肌的功能已经得到了广泛的研究，但对控制和塑造尾巴的内在肌肉组织的研究却很少。在这项研究中，我们测量了内在尾部肌肉的电活动，以确定这些肌肉在稳定的直线运动中是否活跃，并将内在肌肉的招募模式与先前的肌间肌纤维数据进行比较。对5只蓝鳃太阳鱼（Lepomis macrochirus）进行麻醉，并将电极线手术置入共24块内在尾端肌肉中，每次最多13块，活动与尾端脚肌束纤维的同步记录相关联。恢复后，鱼以0.5、1.2和2.0 L / s的速度稳定游动（-1），同时以250帧/ s的速度从侧面、后部和腹部拍摄。速度之间的比较证实了肌肉的恢复随速度的变化有显著的差异。在0.5 L s（-1）时，尾鳍通常不用于推进，游泳主要通过身体波动来完成。在这个速度下，内在的尾肌活动是间歇性和可变的。在1.2和2.0 L s（-1）时，骶上肌和骶下肌分别作用于最背鳍和最腹鳍，以扩大尾鳍的表面积。桡间肌在脊索下纵肌激活后，将单个鳍从背侧向腹侧内收。桡间肌对侧肌肉活动发生在尾鳍穿过平均运动方向和鳍高度最大时，而同侧肋肌活动发生在鳍高度最低时，在速度为1.2和2.0 L s（-1）时，靠近鳍最大漂移点。破裂强度随着游泳速度的增加而增加，这表明尾鳍对施加的水动力载荷的加强。内在尾部肌肉的活动模式表明，这些位于尾部的鱼类最后方的肌肉是在游泳速度增加时首先被调动起来的，而缓慢波动的游泳是由位于尾部尾部和尾部的肌肉纤维提供动力的。
There are approximately 50 muscles that control tail fin shape in most teleost fishes, and although myotomal muscle function has been extensively studied, little work has been done on the intrinsic musculature that controls and shapes the tail. In this study we measured electrical activity in intrinsic tail musculature to determine if these muscles are active during steady rectilinear locomotion, and to compare intrinsic muscle recruitment patterns to previous data on myotomal muscle fibers. Five bluegill sunfish (Lepomis macrochirus) were anaesthetized and electrode wires surgically placed into a total of 24 intrinsic caudal muscles, up to 13 at a time, and activity was correlated with synchronous recordings from myotomal fibers in the caudal peduncle. After recovery, fish swam steadily at speeds of 0.5, 1.2 and 2.0 L s(-1), while filmed from lateral, posterior and ventral views simultaneously at 250 frames s(-1). Comparison among speeds confirmed that muscle recruitment varies significantly with speed. At 0.5 L s(-1), the caudal fin was generally not used for propulsion, and swimming was accomplished primarily through body undulations. Intrinsic caudal muscle activity at this speed was intermittent and variable. At 1.2 and 2.0 L s(-1), the supracarinalis and infracarinalis muscles acted on the dorsal- and ventral-most fin rays, respectively, to expand the surface area of the caudal fin. The interradialis muscles adducted individual fin rays, dorsally to ventrally, following activation of the hypochordal longitudinalis. Contralateral muscle activity of interradialis muscles occurred as the caudal fin crossed the mean direction of travel and fin height was greatest, whereas ipsilateral activity of carinalis muscles occurred near points of maximum excursion of the fin, at speeds of 1.2 and 2.0 L s(-1), after fin height was lowest. Burst intensity increased with swimming speed, suggesting stiffening of the tail fin against imposed hydrodynamic loads. Activity patterns of intrinsic caudal muscles suggest that these most posterior muscles in fishes, located within the tail, are among the very first recruited as swimming speed increases, and that slow undulatory swimming is powered by muscle fibers located posteriorly in the caudal peduncle and tail.