DIFFERENTIATION OF MUSCLE-FIBER TYPES IN ANEUROGENIC BRACHIAL MUSCLES OF THE CHICK-EMBRYO
DIFFERENTIATION OF MUSCLE-FIBER TYPES IN ANEUROGENIC BRACHIAL MUSCLES OF THE CHICK-EMBRYO
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DOI：
10.1002/jez.1402240108
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发表时间：
1982-01-01
影响因子：
--
通讯作者：
BRIERLEY, J
中科院分区：
文献类型：
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作者：
BUTLER, J;COSMOS, E;BRIERLEY, J
用刚孵出的雏鸡进行的交叉神经移植研究表明，外周运动神经元控制着禽类肌肉的表型特征。研究了神经在肌纤维类型的初始表达过程中是否起类似的作用。特定纤维类型的分化发生在胚胎发生的第一周，与肌肉块内神经的渗透一致。周围神经可能与纤维类型的初始分化有关。通过缺失神经管臂段使鸡胚前肢芽无神经原性。为了确保臂肌发育的完全无神经环境，在腹侧根纤维出口前的第[d] 2天进行手术。从第25期（4.5 d）到第45期（19 d）的实验胚胎和对照胚胎进行组织化学分析，通过ag -胆碱酯酶反应检测神经，通过肌球蛋白atp酶反应，在碱和酸预孵育后确定肌肉的纤维类型组成。比较无神经源性肌和对照肌的总容积。在整个分析期间，个体无神经源性和神经支配（对照）肌肉的特征肌球蛋白atp酶谱是相同的。显然，这些酶谱是内源性表达的，在胚胎发生早期不受神经元控制。在没有神经的情况下，从肌生成细胞迁移到前肢芽，通过初级肌肉块的分裂形成单个臂肌的整个过程都按计划进行。由于无神经源性肌肉的生长受损，在胚胎发生期间，周围运动神经最初是肌肉正常生长和最终存活所必需的。它们不参与单个臂肌的初始形成或初始分化。
Cross-reinnervation studies performed ex ovo with newly hatched chicks demonstrate that peripheral motor neruons control the phenotypic characteristics of avian muscles. Whether nerves play a similar role during the initial expression of muscle fiber types was studied. Differentiation of specific fiber types occurs during the 1st wk of embryogenesis, coincidently with the penetration of nerves within muscle masses. Peripheral nerves may be associated with the initial differentiation of fiber types. Anterior limb buds of the chick embryo were rendered aneurogenic by deletion of the brachial segment of the neural tube. To ensure a completely aneurogenic environment for developing brachial muscles, surgery was performed at day [d] 2 in ovo before the exit of ventral root fibers. Experimental and control embryos from stage (st) 25 (4.5 d) through st 45 (19 d) were analyzed histochemically by a Ag-cholinesterase reaction to detect nerves and by the myosin ATPase reaction, following alkali and acid preincubation, to determine the fiber type compositon of the muscles. The total volume of aneurogenic and control muscles was compared. The characteristic myosin ATPase profiles of individual aneurogenic and innervated (control) muscles were identical throughout the entire period analyzed. Evidently, these enzymic proifles are endogenously expressed and are not under neuronal control during early embryogenesis. The entire sequence of events from the migration of myogenic cells to the anterior limb bud through the division of the primary muscle masses to form individual brachial muscles proceeded on schedule in the absence of nerves. Since the growth of aneurogenic muscles was impaired, during embryogenesis, peripheral motor nerves are initially necessary for the proper growth of muscles and, ultimately, for their survival. They are not involved with the initial formation or initial differentiation of individual brachial muscles.