신경 교차연결 후 흰쥐 골격근섬유의 마이오신 동질형의 변화

Abstract

Skeletal muscle fibers of the mammals could be classified according to the activity of the enzyme in the mitochondria, i. e. , nicotinamide dinucleotide-tetrazolium reductase (NADH-TR), succinate dehydrogenase (SDH) and myofibrillar ATPase activity of myosin and contraction velocity. Muscle fiber types could be changed by exercise and nerve stimuli and also diseases could evoke many changes. The myosin isozymes in adult skeletal muscle can be classified into two major types, fast and slow Isozymes. These fast and slow isozymes differ in both their heavy and light chain subunits. Myosin isolated fast-contracting muscle contains three different kinds of light chain (LClf, LC2f, LC3f) and it contains two kinds of light chain (LCls, LC2s) in slow-contracting muscle on SDS/polyacrylamide gels. These various isoforms of the myosin heavy chains and light chains are known to be closely related to the histochemical reaction of the myosin ATPase. The purpose of this study was to define the isomyosins in the fast extensor digitorum longus (EDL) muscle and the slow soleus muscle of the rat hindlimb in an analysis of the normal state and after cross innervation. For this purpose, we performed SDS gel electrophoresis of myosin isozymes with respect to the whole muscle and individual muscle fibers. In cross Innervation group, rapld contraction muscle type of myosin Isoform was identified in slow contraction muscle, while slow contraction muscle type of myofibrillar protein isofsym was identified in rapid contraction muscle. The newly formed muscle fiber after the cross innervation contains different myofibrillar protein isoforms from the same muscle fiber type in normal control group. From the above results, It was identified that muscle changes after the cross innervation occured at the molecular level of myosin isoform. And the changes of muscle fiber types in slow contraction muscle to that in rapid contraction muscle fiber types were evident in morphological and myofibrillar protein level.