Further evidence of incomplete neural control of muscle properties in cat tibialis anterior motor units.
Further evidence of incomplete neural control of muscle properties in cat tibialis anterior motor units.
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猫胫骨前运动单位肌肉特性的不完全神经控制的进一步证据。
DOI：
10.1152/ajpcell.1995.268.2.c527
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Edgerton,VR
中科院分区：
文献类型：
--
作者：
Unguez,GA;Roy,RR;Pierotti,DJ;Bodine-Fowler,S;Edgerton,VR
为探讨运动神经元在维持其支配的肌纤维表型中的作用，在猫胫骨前肌中切断并缝合支配前室的神经支，观察了肌球蛋白重链(MHC)的表达、琥珀酸脱氢酶(SDH)活性和横截面积(CSA)。获得了每个MHC谱、每个对照肌肉和每个自支配肌肉的SDH活性和运动单位和非运动单位纤维的CSA的平均值、范围和变异系数。采用标准的腹根细丝测试技术，从自体神经支配的肌肉中分离出8个运动单位，进行生理学测试，并与来自对照肌肉的4个运动单位进行比较。来自自神经支配肌肉的运动单位可以被归类为与对照胫前肌相同的生理类型。属于一个单位的肌肉纤维通过重复刺激来耗尽糖原，并在高碘酸希夫染色的冰冻切片中进行鉴定。而对照单位的肌肉纤维表达相似的MHC，而来自自我神经肌肉的每个运动单位包含一种纤维类型的混合物。然而，在每个运动单位中，具有相同MHC轮廓的纤维占主导地位。自神经支配后，单位内不同MHC类型的纤维与对照肌肉中发现的纤维之间的平均SDH活性的相对差异是相似的，即FAST-2<；FAST-1<；或=Slow MHC纤维。
To examine the influence of a motoneuron in maintaining the phenotype of the muscle fibers it innervates, myosin heavy chain (MHC) expression, succinate dehydrogenase (SDH) activity, and cross-sectional area (CSA) of a sample of fibers belonging to a motor unit were studied in the cat tibialis anterior 6 mo after the nerve branches innervating the anterior compartment were cut and sutured near the point of entry into the muscle. The mean, range, and coefficient of variation for the SDH activity and the CSA for both motor unit and non-motor unit fibers for each MHC profile and from each control and each self-reinnervated muscle studied was obtained. Eight motor units were isolated from self-reinnervated muscles using standard ventral root filament testing techniques, tested physiologically, and compared with four motor units from control muscles. Motor units from self-reinnervated muscles could be classified into the same physiological types as those found in control tibialis anterior muscles. The muscle fibers belonging to a unit were depleted of glycogen via repetitive stimulation and identified in periodic acid-Schiff-stained frozen sections. Whereas muscle fibers in control units expressed similar MHCs, each motor unit from self-reinnervated muscles contained a mixture of fiber types. In each motor unit, however, there was a predominance of fibers with the same MHC profile. The relative differences in the mean SDH activities found among fibers of different MHC profiles within a unit after self-reinnervation and those found among fibers in control muscles were similar, i.e., fast-2 < fast-1 < or = slow MHC fibers.(ABSTRACT TRUNCATED AT 250 WORDS)