动、静力因素对动物运动终板形态结构变化的影响

HISTOLOGICAL CHANGES OF THE MOTOR END—PLATES OF MICE UNDER INFLUENCE OF DYNAMIC AND STATIC FACTORS

运动终板是神经冲动对肌肉发挥作用的转化装置(transformator)。神经兴奋通过终板部的物理、化学变化使肌肉的化学能转变成机械能(动能)。因此,在肌肉运动过程中,神经肌突触部起着重要的转化作用。本文将从加强肌肉的动、静力因素训练过程中考察对神经肌突触——运动终板的影响,以期在神经末梢的机能形态学方面进行探讨。

Fifteen mice,were divided into 3 groups,each was trained to adopt a particular functional state of muscular activity for a long term.The histological changes of their motor end-plates were examined by means of the Bielschowsky-Gros and the Ranvier’s gold chloride techniques.The results were summarized as follows:1.It was found that,by increasing the dynamic or static functional activity of mus-cles of the mice,the motor end-plates were enlarged in size and their nuclei were in-creased in number,as compared with those of the control group.2.The size of the nuclei of the end-plates of both experimental groups was not equally affected,e.g.,the nuclei in the static group were larger,while those in the dyna-mic group were comparatively smaller.3.Under the influence of the dynamic or static muscular exercise,the end-plates increased in their sizes,more so in the static than in the dynamic group,while the control group remained to be the smallest.The diameter had a tendency to increase along the long axis in the dynamic group,and along the transverse axis in the static group;hence the end plate appeared to be oblong in the former and oval in the latter group.4.After a long term of muscular exercise,whether dynamic or static in nature,the nerve fibers supplying the end-plates increased in thickness and degree of complexity of ramification.There were some unidentified cells with annular nucleus in the vicinity of the end-plate.5.Mechanism of the changes of the motor end-plates was discussed in the light of functional morphology.