MAMMALIAN MYOGENESIS SUBSEQUENT TO FETAL DENERVATION

在体内肌肉发生与发育和 胎儿神经系统的成熟。因为哺乳动物的胎儿还没有 很容易被操纵，我们对神经肌肉的许多了解 发展中的关系是从发展的研究中获得的 小鸡。最近的研究表明，哺乳动物的神经-肌肉关系 胎儿可能与雏鸡的胎儿不同。一种允许激光的新技术 切除胎儿腰骶区，小鼠脊髓， 在不影响胎儿存活和进一步成熟的情况下， 以确定胎儿去神经对肌管形成的影响， 哺乳动物肌管存活和肌管多样性的产生 肌肉。将用电子显微镜进行评估，定量 形态计量学、凝胶电泳法和免疫细胞化学。这些研究 将提供有关基因决定的基因改变的信息 由环境因素(即发育)引起的肌肉发生的模式 运动神经元)。对轴突切断术的影响知之甚少，在 胎儿期的不同，对哺乳动物运动神经元存活的影响。技术 允许横断脊神经的腹根或横断 坐骨神经将可以确定哺乳动物的轴突是否可以 是否(以及在什么条件下)可以神经支配轴突切断后存活 横纹肌。如果轴突切断的运动神经元存活，延迟的影响 神经支配和/或胎儿一过性失神经对肌肉发育的影响 被评估。如果它们不能存活，大小和位置的变化 运动神经元池至部分失神经的成人肌肉 在胎儿发育过程中将被确定。将与以下人员一起进行评估 电子显微镜、生理学和对小鼠脊髓的检查 肌肉注射HRP。拟议的研究与以下方面有关 人的发展。

In vivo myogenesis occurs simultaneously with the development and maturation of the fetal nervous system. Because the mammalian fetus has not been easily manipulated, much of what we know about nerve-muscle relationships during development has been gained from studies of developing chick. Recent studies suggest that nerve-muscle relationships in mammalian fetuses may differ from those in chick. A new technique which permits laser ablation of the lumbosacral region of the fetal, murine spinal cord, without interfering with fetal viability and further maturation, will allow us to determine the effect of fetal denervation on myotube formation, myotube survival and on the generation of myotube diversity in mammalian muscles. Evaluations will be made with electron microscopy, quantitative morphometry, gel electrophoresis and immunocytochemistry. These studies will provide information concerning alterations in genetically determined patterns of myogenesis by an environmental factor (i.e., the developing motoneuron). Little is known about the effects of axotomy, performed at various fetal stages, on the survival of mammalian motoneurons. Techniques which permit transection of the ventral roots of spinal nerves or of the sciatic nerve will allow determination of whether mammalian axons can survive axotomy and whether (and under what conditions) they can innervate striated muscle. If axotomized motoneurons survive, the effect of delayed innervation and/or transient fetal denervation on muscle development will be assessed. If they fail to survive, alterations in the size and location of motoneuron pools to adult muscles subjected to partial denervation during fetal development will be determined. Evaluations will be made with electron microscopy, physiology and by examining the spinal cords of mice whose muscles were injected with HRP. The proposed studies are relevant to human development.