Du Trina Y, Standen Emily M
Department of Biology, McGill University, Redpath Museum, 859 Sherbrooke Street West, Montreal, QC, Canada H3A 0C4.
Department of Biology, University of Ottawa, Gendron Hall, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5
J Exp Biol. 2017 Oct 1;220(Pt 19):3406-3410. doi: 10.1242/jeb.162909. Epub 2017 Aug 7.
Muscle fiber types in the pectoral fins of fishes have rarely been examined, despite their morphological and functional diversity. Here, we describe the distribution of fast and slow muscle fibers in the pectoral fins of , an amphibious, basal actinopterygian. Each of the four muscle groups examined using mATPase staining showed distinct fiber-type regionalization. Comparison between fish raised in aquatic and terrestrial environments revealed terrestrially reared fish possess 28% more fast muscle compared with aquatically reared fish. The pattern of proximal-distal variation in the abductors differed, with a relative decrease in fast muscle fibers near the pectoral girdle in aquatic fish compared with an increase in terrestrial fish. Terrestrially reared fish also possess a greater proportion of very small diameter fibers, suggesting that they undergo more growth via hyperplasia. These observations may be a further example of adaptive plasticity in , allowing for greater bursts of power during terrestrial locomotion.
尽管鱼类胸鳍中的肌纤维类型在形态和功能上具有多样性，但很少有人对其进行研究。在这里，我们描述了一种两栖的、基干辐鳍鱼类胸鳍中快肌纤维和慢肌纤维的分布情况。使用mATPase染色法对四个肌肉群进行检查，结果显示每个肌肉群都有明显的纤维类型区域化。对在水生和陆生环境中饲养的鱼进行比较发现，与水生饲养的鱼相比，陆生饲养的鱼的快肌多28%。外展肌近端到远端的变化模式有所不同，与陆生鱼增加相比，水生鱼靠近胸带处的快肌纤维相对减少。陆生饲养的鱼还拥有更大比例的非常小直径的纤维，这表明它们通过细胞增生经历了更多的生长。这些观察结果可能是该鱼类适应性可塑性的又一个例子，使其在陆地运动期间能够产生更大的爆发力。
