POSTNATAL DEVELOPMENT OF RESPIRATORY ACTIVITES

呼吸神经元的发育和成熟 运动神经元的放电特性将在两天内进行检查 两个月大的猪。将追求三个具体目标：(A) 确定吸气次数与年龄相关的差异 带有轴突的神经元终止于膈运动神经元池和 对肺传入信息的反应；(B)研究与年龄有关的 神经元对低氧反应的变化及神经元鉴定 可介导膈运动神经元的缺氧反应； (C)比较膈神经、喉返神经传出放电 和舌下运动神经元在调制过程中的差异 中枢模式发生器，对肺传入的反应 低氧时的输入和反应。实验将是 在萨凡麻醉的仔猪身上进行；麻醉深度将 通过记录EEG、EKG和动脉血压进行监测。 吸气神经元将被细胞外记录并做出反应 到肺传入的输入将使用No 通货膨胀测试。在迷走神经切断的仔猪中，神经元对 低氧将根据功率谱的变化进行分类。 对于所有神经元，单个神经元记录的验证将是 使用尖峰间隔分布确定的，并且 存在与膈运动神经元的兴奋性连接将 使用尖峰触发的平均值来确定。调制方式 常见的中枢模式发生器的神经放电将是 使用功率和相干频谱分析进行评估。年龄- 相关结果将通过以下统计比较来确定 不同日龄的仔猪。这项研究将提供新的 关于延髓吸气发育的信息 神经元以及膈神经、喉返神经和舌下神经 运动神经元。这一信息在临床上很重要，因为 对新生儿呼吸障碍，即婴儿呼吸窘迫综合征、呼吸暂停的研究， 在对传入输入的反应中隐含的不成熟 突触连接是致病因素。

The development and maturation of respiratory neuron and motoneuron discharge properties will be examined in two day to two month old swine. Three specific aims will be pursued: (a) to determine age-related differences in numbers of inspiratory neurons with axons terminating in phrenic motoneuron pool and in responses to pulmonary afferent inputs; (b) to study age-related changes of neuronal responses to hypoxia and to identify neurons which could mediate hypoxic responses of phrenic motoneurons; (c) to compare efferent discharges of phrenic, recurrent laryngeal and hypoglossal motoneurons for differences in modulation by central pattern generators, responses to pulmonary afferent inputs, and responses during hypoxia. Experiments will be performed in Saffan anesthetized piglets; depth of anesthesia will be monitored by recording EEG, EKG and arterial blood pressure. Inspiratory neurons will be recorded extracellularly and responses to pulmonary afferent inputs will be determined using the No Inflation Test. In vagotomized piglets, neuronal responses to hypoxia will be classified according to changes in power spectra. For all neurons verification of single neuron recordings will be determined using interspike interval distributions, and the presence of excitatory connections with phrenic motoneurons will be determined using spike-triggered averaging. Modulation of nerve discharges by common central pattern generators will be evaluated using power and coherence spectral analyses. Age- dependent results will be determined by statistical comparisons of piglets at different ages. This research will provide new information regarding the development of medullary inspiratory neurons as well as phrenic, recurrent laryngeal and hypoglossal motoneurons. This information is clinically important since studies of neonatal breathing disturbances, i.e., SIDS, apnea, have implicated immaturities in responses to afferent inputs and in synaptic connections as etiological factors.