Gauthier G F, Padykula H A
J Cell Biol. 1966 Feb;28(2):333-54. doi: 10.1083/jcb.28.2.333.
A comparative investigation of the mammalian diaphragm has revealed a correlation between certain cytological aspects of red and white muscle fibers and functional activity. This skeletal muscle presents the advantage of a similar and constant function among the mammals, but its functional activity varies in a quantitative manner. Both the rate of breathing (and hence the rate of contraction of the diaphragm) and metabolic activity are known to be inversely related to body size; and this study has demonstrated a relationship between cytological characteristics of the diaphragm and body size of the animal. Small fibers rich in mitochondria (red fibers) are characteristic of small mammals, which have high metabolic activity and fast breathing rates; and large fibers with relatively low mitochondrial content predominate in large mammals, which have lower metabolic activity and slower breathing rates. In mammals with body size intermediate between these two groups (including the laboratory rat), the diaphragm consists of varying mixtures of fiber types. In general, the mitochondrial content of diaphragm fibers is inversely related to body size. It appears, then, that the red fiber reflects a high degree of metabolic activity or a relatively high rate of contraction within the range exhibited by this muscle.
对哺乳动物膈肌的一项比较研究揭示了红肌纤维和白肌纤维的某些细胞学特征与功能活动之间的相关性。这种骨骼肌在哺乳动物中具有相似且恒定功能的优势，但其功能活动在数量上有所不同。已知呼吸频率（进而膈肌的收缩频率）和代谢活动都与体型呈负相关；并且这项研究已经证明了膈肌的细胞学特征与动物体型之间的关系。富含线粒体的小纤维（红纤维）是小型哺乳动物的特征，它们具有高代谢活动和快速呼吸频率；而线粒体含量相对较低的大纤维在大型哺乳动物中占主导地位，它们具有较低的代谢活动和较慢的呼吸频率。在体型介于这两组之间的哺乳动物（包括实验大鼠）中，膈肌由不同类型纤维的混合组成。一般来说，膈肌纤维的线粒体含量与体型呈负相关。那么，似乎红纤维反映了该肌肉所表现出的范围内的高度代谢活动或相对较高的收缩率。
