DEVELOPMENTAL REGULATION OF NEURON NUMBER

神经元数量的发育调节

• 批准号: 3449680
• 负责人: DAVID G SPERRY
• 金额: $ 5.73万
• 依托单位: UNIVERSITY OF DELAWARE
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-07-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3449680
• 关键词: cell death; cell morphology; cell population study; electron microscopy; fresh water environment; histology; immature animal; limbs; membrane activity; motor neurons; muscle cells; myofibrils; neural information processing

How the size of adult neuron populations is regulated is not understood although the information is relevant to explaining how differences and/or similarities in neuron population sizes are effected through development. One possibility is that neuron populations are matched to their postsynaptic targets through competition for connections, and that neuronal cell death eliminates those neurons that are unsuccessful. For anuran amphibians in particular, it is unclear that this is true for the neuron populations innervating the limbs since limb size and motoneuron population size (i.e., neuron number) appear to be poorly correlated in cases where surgery altered normal development. The proposed research will examine the regulation of motoneuron numbers in the lumbar lateral motor column in three groups of the anuran amphibian, Xenopus laevis: normally-developing, propylthiouracil-treated and triploids. Two likely motoneuron number regulators (muscle fiber number and hindlimb muscle volume) and the size of the motoneuron population (cell number and mean cell size) will be measured in individuals from six developmental stages. The correlations between motoneuron population size and these two aspects of the limb have never been determined, and the variations in cell size and cell number that apparently occur between these three types of X. laevis can be used to test the idea that a size match explains motoneuron number regulation. These experiments avoid particular problems associated with surgery. If these aspects of the hindlimb do regulate neuron population size, then neuron populations of abnormal size can readily be related to developmental events that change these features of limbs. If these aspects of hindlimb size are not regulating motoneuron numbers, then other aspects of the hindlimb need to be identified and their roles tested, or other modes of neuron number regulation need to be investigated. Identifying any developmental regulators of neuron numbers will allow a better understanding of the significance that cell death has in producing appropriately size neuron populations throughout the nervous system.

成年神经元数量的大小是如何调节的还不清楚 尽管该信息与解释差异和/或 神经元群体大小的相似性是通过发育来实现的。 一种可能性是，神经元的数量与它们的 突触后靶点通过竞争连接，神经元 细胞死亡会消除那些不成功的神经元。 对于无尾目 特别是两栖动物，目前还不清楚这是否适用于神经元 由于肢体大小和运动神经元数量， 尺寸（即，神经元数量）似乎相关性较差的情况下， 手术改变了正常发育。 拟议的研究将审查 腰椎外侧运动柱运动神经元数量的调节 三组无尾两栖动物，非洲爪蟾：正常发育， 丙硫氧嘧啶处理和三倍体。 两个可能的运动神经元数 调节因子（肌纤维数量和后肢肌肉体积）和大小 将测量运动神经元群体（细胞数量和平均细胞大小 在六个发育阶段的个体中。 之间的相关性 运动神经元群体的大小和肢体的这两个方面从来没有 已经确定，以及细胞大小和细胞数量的变化， 显然发生在这三种X之间。左心耳可用于测试 大小匹配解释运动神经元数量调节的想法。 这些 实验避免了与手术相关的特殊问题。 如果这些 后肢的某些方面确实调节神经元群体的大小， 异常规模的种群很容易与发育事件相关 来改变肢体的这些特征。 如果后肢大小的这些方面 不调节运动神经元的数量，那么后肢的其他方面需要 或其他模式的神经元数量 监管需要研究。 识别任何发展 神经元数量的调节器将使我们更好地理解 细胞死亡在产生适当大小神经元方面具有重要意义 在整个神经系统中。