Activity-unrelated neural control of myogenic factors in a slow muscle
Activity-unrelated neural control of myogenic factors in a slow muscle
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DOI：
10.1002/mus.20433
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发表时间：
2006-01-01
期刊：
影响因子：
3.4
通讯作者：
Edgerton, VR
中科院分区：
文献类型：
--
作者：
Hyatt, JPK;Roy, RR;Edgerton, VR
骨骼肌的特性受神经和非神经因素的调节，其中神经因素既可通过活动依赖性机制调节，也可通过活动非依赖性机制调节。鉴于快速肌肉的日常激活比慢速肌肉少得多，我们假设大鼠比目鱼肌（慢速肌肉）的生肌特性将更多地依赖于活动依赖性因素而不是活动独立性因素。肌肉质量，MyoD，肌细胞生成素的mRNA和蛋白水平，卫星细胞增殖和分化率（溴脱氧尿苷掺入）进行了检查，在3，14和28天后，无论是脊髓隔离（S1，神经肌肉连接完整，最低限度的激活）或去神经支配（无神经影响）。在每个时间点，S1和去神经组的比目鱼肌萎缩是相似的，尽管肌细胞生成素的全肌肉表达的增加，在较小程度上，MyoD在S1中比去神经比目鱼肌低（P < 0.05）。与失神经比目鱼肌相比，S1肌卫星细胞的增殖和分化以及结缔组织细胞的有丝分裂活性明显降低（P < 0.05）。在某些情况下，直到后来的时间点才观察到这些变化，即，14或28天这些结果表明，运动神经元，神经支配的慢比目鱼肌有一个显着的调制的影响，通过机制，是独立的激活对肌肉的一些特性。然而，这些独立于活动的调制影响，是在慢比目鱼肌比以前观察到的快速肌肉。
The properties of skeletal muscles are modulated by neural and nonneural factors, and the neural factors can be modulated by activity-independent as well as activity-dependent mechanisms. Given that daily activation of fast muscles is considerably less than of slow muscles, we hypothesized that the myogenic properties of the rat soleus (a slow muscle) would be more dependent on activity-dependent than activity-independent factors. Muscle mass, MyoD, and myogenin mRNA and protein levels, and satellite cell proliferation and differentiation rates (bromodeoxyuridine incorporation) were examined at 3, 14, and 28 days after either spinal cord isolation (Sl, neuromuscular connectivity intact with minimal activation) or denervation (no neural influence). Soleus atrophy was similar in the Sl and denervated groups at each time point, although increases in whole-muscle expression of myogenin and, to a lesser degree, MyoD were lower (P < 0.05) in Sl than denervated soleus muscles. Proliferation and differentiation of satellite cells, as well as mitotic activity of connective tissue cells, were lower (P < 0.05) in Sl than denervated soleus muscles. In some instances, these changes were not observed until the later time points, i.e., 14 or 28 days. These results demonstrate that the motoneurons that innervate the slow soleus muscle have a significant modulatory influence on some muscle properties via mechanisms that are independent of activation. These activity-independent modulatory influences, however, are less in the slow soleus than previously observed in fast muscles.