DEVELOPMENTAL CONTROL OF THE DIAPHRAGM AND UPPER AIRWAYS

最近的理论认为，有几个原因，突然婴儿 死亡综合征（SIDS）。 一种可能的病因是严重的混合性和 睡眠中的阻塞性呼吸暂停 有人提出，这一特殊的 脑干神经元发育迟缓导致的功能障碍 控制上呼吸道相对于这些神经元的开放性 控制隔膜。 为了验证这个假设，必须有一个 控制神经元正常发育的基础数据 上呼吸道和膈肌。 这份提案将比较 舌下神经运动神经元的发育过程 舌颏舌肌与脊髓运动神经元的肌肉， 使横膈膜受神经支配。 第一个项目将研究膈神经的正常发育 运动神经元，支配膈肌，并比较这些结果的数据 从成年人。 第二个项目将生成颏舌的数据 在成人的运动神经元进行比较，与相同的神经元在各种 发育阶段 第三个项目将描述 颏舌肌运动神经元的发育， 膈运动神经元 这些对舌下神经运动神经元的研究 产生的重要信息的神经控制的发展 上呼吸道，但可能，此外，反映了更多的全球性的状态， 其他脑干神经元的发育， 节律或睡眠状态。 这两个运动神经元群的解剖和生理变化 将在出生后早期的三个不同阶段进行比较。 运动神经元的各种电生理特性将被 通过细胞内记录确定，以及它们的细胞 形态学将从细胞内 用辣根过氧化物酶（HRP）染色。 生理 研究运动神经元的特性以评估其成熟度 包括静息膜电位的值， 动作电位过冲，后超极化持续时间， 输入电阻、基强度、轴突的传导速度和轴突的传导速度 存在复发性抑制和/或电偶联。 以类似的 时尚，解剖成熟度将通过偏心率进行评估， 胞体、膜表面积、树突数 投射到不同的突触区域， 树突分支、树突棘和轴突侧支的数量。

Recent theories propose that there are several causes of Sudden Infant Death Syndrome (SIDS). One probable etiology is severe mixed and obstructive apnea during sleep. It has been proposed that this particular dysfunction results from a delayed development of the brainstem neurons controlling the patency of the upper airways relative to those neurons controlling the diaphragm. To test this hypothesis, there must be a fundamental data base on the normal development of the neurons controlling the upper airways and diaphgragm. This proposal will compare the time course of development of hypoglossal motoneurons innervating the genioglossus muscle of the tongue with that of the spinal motoneurons that innervate the diaphragm. The first project will investigate the normal development of phrenic motoneurons which innervate the diaphragm and compare these results to data from the adult. The second project will generate data on the genioglossal motoneuron in the adult for comparison with the same neurons at various developmental stages. The third project will describe the time course of development in the genioglossal motoneurons for comparisons with that of the phrenic motoneurons. These studies of hypoglossal motoneurons will yield important information on the development of neural control of the upper airways but may, in addition, reflect the more global state of development of other brainstem neurons which may generate respiratory rhythm or sleep states. The changes in anatomy and physiology of these two motoneuron populations will be compared at three different stages of early postnatal life. Various electrophysiological properties of the motoneurons will be determined by intracellular recording, and fine details of their cellular morphology will be revealed from histological analyses after intracellular staining with the enzyme, horseradish peroxidase (HRP). The physiologic properties of the motoneuron to be investigated to assess their maturity include the value of the resting membrane potential, amplitude of the overshoot of the action potential, duration of the after hyperpolarization, input resistance, rheobase, the conduction velocity of its axon and the presence of recurrent inhibition and/or electrical coupling. In a similar fashion, anatomical maturity will be evaluated by the eccentricity of the cell body, amount of membrane surface area, the number of dendrites projecting into various synaptic fields, complexity of the pattern of dendritic branching, number of dendritic spines and axonal collaterals.