Rivero J L, Talmadge R J, Edgerton V R
Department of Comparative and Pathological Anatomy, Faculty of Veterinary Science, University of Cordoba, Spain.
Histochem Cell Biol. 1999 Apr;111(4):277-87. doi: 10.1007/s004180050358.
Myofibrillar ATPase (mATPase), succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) activities and cross-sectional area (CSA) were measured in fibres of rat medial gastrocnemius muscle using quantitative histochemistry. The same fibres were typed immunohistochemically using monoclonal antibodies specific to selected myosin heavy chain (MHC) isoforms. The values of mATPase, SDH, GPD and CSA formed a continuum, but significant differences in mean values were observed among fibre types of presumed homogeneous MHC content. Type I fibres had the lowest mATPase activity, followed in rank order by type IIA < type IID/X < type IIB. Type IIA fibres had the highest SDH activity, followed in rank order by type IID/X > type I > type IIB. The mean GPD activity was consistently ranked according to fibre type such that type IIB > type IID/X > type IIA > type I. Type IIA fibres were the smallest, type IIB fibres were the largest and types I and IID/X were of intermediate size. Significant interrelationships between mATPase, SDH, GPD and CSA values were found on a fibre-to-fibre basis. Consequently, discrimination of fibres according to their MHC content was possible on the basis of their mATPase, SDH, GPD and CSA profiles. These intrafibre interrelationships suggest that the MHC isoform is associated with phenotypic differences in contractile, metabolic and size properties of muscle fibre types.
采用定量组织化学方法，测定了大鼠腓肠肌内侧肌纤维中的肌原纤维ATP酶（mATPase）、琥珀酸脱氢酶（SDH）和α-甘油磷酸脱氢酶（GPD）活性以及横截面积（CSA）。使用针对选定肌球蛋白重链（MHC）亚型的单克隆抗体，对相同的肌纤维进行免疫组织化学分型。mATPase、SDH、GPD和CSA的值形成一个连续体，但在假定MHC含量均匀的纤维类型之间，观察到平均值存在显著差异。I型纤维的mATPase活性最低，其次依次为IIA型<II D/X型<IIB型。IIA型纤维的SDH活性最高，其次依次为II D/X型>I型>IIB型。平均GPD活性始终按照纤维类型排序，即IIB型>II D/X型>IIA型>I型。IIA型纤维最小，IIB型纤维最大，I型和II D/X型纤维大小居中。在纤维水平上发现了mATPase、SDH、GPD和CSA值之间存在显著的相互关系。因此，根据其mATPase、SDH、GPD和CSA谱，可以根据肌纤维的MHC含量对其进行区分。这些纤维内的相互关系表明，MHC亚型与肌纤维类型的收缩、代谢和大小特性的表型差异有关。
