English A W, Letbetter W D
Anat Rec. 1982 Oct;204(2):123-30. doi: 10.1002/ar.1092040205.
The lateral gastrocnemius muscle of cats can be divided into four discrete subvolumes or compartments which are supplied by the primary branches of its muscle nerve. The histochemical profile of each compartment was determined from the reaction for myosin ATPase after acid preincubation. Fibers were classified as fast-twitch glycolytic (FG), fast-twitch oxidative-glycolytic (FOG), or slow-twitch oxidative (SO). Each compartment in each cat examined was found to contain a relatively uniform distribution of different types of fibers. The most proximal LG compartment contains mainly type FG fibers, with relatively few type SO fibers; the most distal compartment, while still predominated by type FG fibers, contains a significantly larger proportion of type SO fibers. The histochemical profile of the intermediate compartments indicates that they contain fibers which lie intermediate in composition between these two. These results are consistent with the notion that LG compartments consist of aggregations of motor units, arranged such that muscle fibers comprising a single motor unit are contained within a single compartment.
猫的外侧腓肠肌可分为四个独立的亚体积或肌室，由其肌神经的主要分支供血。通过酸预孵育后肌球蛋白ATP酶反应确定每个肌室的组织化学特征。纤维被分类为快肌糖酵解型（FG）、快肌氧化糖酵解型（FOG）或慢肌氧化型（SO）。在每只被检查的猫中，每个肌室都发现含有相对均匀分布的不同类型纤维。最靠近近端的外侧腓肠肌肌室主要包含FG型纤维，SO型纤维相对较少；最远端的肌室虽然仍以FG型纤维为主，但含有比例显著更高的SO型纤维。中间肌室的组织化学特征表明，它们所含纤维的组成介于这两者之间。这些结果与以下观点一致，即外侧腓肠肌肌室由运动单位聚集而成，其排列方式使得构成单个运动单位的肌纤维包含在单个肌室内。
