骨骼肌两型肌纤维的α运动神经元的形态和分布  

The appearance and idstribution of ɑ-motor neuron of muscle fiber Ⅰ and Ⅱ type

作　　者：周播江[1] 史楠[1] 陆奎顺[1] 范学斌[1] 黄永坚[1] 

机构地区：[1]遵义医学院人体解剖教研室,贵州遵义563003

出　　处：《遵义医学院学报》2009年第2期99-102,共4页Journal of Zunyi Medical University

摘　　要：目的通过观察趾长伸肌运动神经元(EDL-Mn)和比目鱼肌运动神经元(SOL-Mn)的形态特点及其在脊髓的分布特征,探讨骨骼肌两型肌纤维的α运动神经元的形态特征及其与两型肌纤维功能之间的关系。方法应用改良的肌球蛋白ATP酶组织化学染色法观察5只健康6～8周龄Wistar大鼠的趾长伸肌和比目鱼肌的肌纤维类型的构成特点;应用神经束路逆行示踪法追踪20只健康6～8周龄Wistar大鼠的趾长伸肌和比目鱼肌的运动神经元。结果趾长伸肌Ⅱ型纤维占83%～92%,比目鱼肌I型纤维占87%～97%。支配趾长伸肌的神经元较大,以大多角形为主,主要分布在脊髓L4、L5节段的前角前群(核)外侧。支配比目鱼肌的神经元以圆形为主,主要分布在脊髓L4、L5和L6节段的前角前群(核)内侧。结论支配趾长伸肌的运动神经元与支配比目鱼肌的运动神经元在数量和分布定位上存在差异,虽不能充分说明支配I型纤维和Ⅱ型纤维的运动神经元一定存在同样差异。但其面积方面的差异说明了支配Ⅱ型(快肌)纤维的神经元大于支配Ⅰ型(慢肌)纤维的神经元。Objective To compare the differences of motor neurons dominated two muscle fiber types , we investigated the appearance and distribution of motor neurons which dominate extensor digitorum longus （EDL） and soleus （SOL） in spinal cord. Methods The distribution feature of muscle fiber types of EDL and SOL was observed by Myosin ATPase staining method and the appearance and distribution of motoneurons （Mn） dominated EDL and SOL was investigated by retrograde fluorescence and HRP tracing. Results The muscle fiber Ⅱ type of EDL was from eighty-three peroent to ninety-two percent, The muscle fiber Ⅰ type of SOL was from eighty-seven to ninety seven peroent. EDL-Mns were mainly bigger polygon and were distributed in lateral anterior nucleus of lateral motoneuron columns in spinal segment L4 and L5, SOL- Mns were mainly smaller round and were distributed in medial anterior nucleus of lateral motoneuron columns in spinal segment L4, L5 and L6. Conclusions There were some differences in numbers, distribution and areas between EDL-Mns and SOL-Mns. Though their differences in numbers and distribution can not thoroughly prove that there must be the same differences between the motoneurons of muscle fiber Ⅰ and Ⅱ type, their discrepancy of areas demonstrated that the motoneurons of the muscle fiber Ⅱ （fast-twitch muscle） type is bigger than the motoneurons of the muscle fiber Ⅰ （slowtwitch muscle） type.

关 键 词：趾长伸肌 比目鱼肌 肌纤维型 运动神经元 

分 类 号：R322.81[医药卫生—人体解剖和组织胚胎学]