CONTROL OF FETAL AND NEONATAL BREATHING

我们希望1）定义子宫内的觉醒，以评估其影响 胎儿行为状态对呼吸的影响; 2）发现为什么反应 新生儿缺氧包括短暂的过度通气， 换气不足 在项目#1中，我们将使用眼动，睁开眼睛，头部 单突触和多突触反射的运动和大小来确定胎儿 清醒 一旦完成，二氧化碳的作用，皮肤刺激， 冷刺激、给药和其他程序（中脑 横断）对胎儿呼吸的影响将结合 行为状态的变化。 我们想知道这些不同的刺激 因为胎儿行为状态的改变而改变呼吸。 为 例如，我们想知道胎儿是否会增加通气， 在他清醒之前或只有在他清醒时才对二氧化碳有反应。 理解 在子宫内引起觉醒的因素可能有助于我们进一步了解 为什么胎儿会在分娩时醒来 测量将包括 皮层电图（ECoG），眼电图（EOG），气管压力， 肌电图血压和心率。 直接观察 使用光纤装置（Olympus，型号BF 3C 4）制造胎儿。 在项目#2中，急性和慢性实验将在小猫和 知道新生羔羊呼吸控制回路处于什么水平缺氧 产生呼吸抑制。 是在外围还是中央 化学感受器水平，在呼吸肌，或者是一个问题， 胸壁和腹部的机械连接 测量将 包括来自颈动脉和膈神经、脑动脉 肋间肌电图，食管压力，通气，肺泡和动脉 气. 在传统的羊肉制备中，行为状态的测量 将包括颈部肌肉的ECoG、EOG和EMG。 如果我们发现了原因 缺氧在生命早期抑制通气，我们可以理解为什么呼吸 在子宫内是周期性的，为什么新生儿呼吸暂停如此频繁 期

We want 1) to define wakefulness in utero in order to assess the influence of fetal behavioral state on breathing; and 2) to discover why the response to hypoxia in neonates consists of transient hyperventilation followed by hypoventilation. In project #1, we will use eye movements, open eyes, head movement and size of mono- and polysynaptic reflexes to define fetal wakefulness. Once this is done, the effect of CO2, cutaneous stimulation, cold stimulation, administration of drugs and other procedures (mid-brain transection) on fetal breathing will be assessed in conjunction with changes in behavioral state. We want to know whether these various stimuli change breathing because of a change in fetal behavioral state. For example, we want to know whether the fetus increases ventilation in response to CO2 before or only when he is awake. Understanding of the factors which induce wakefulness in utero may help us to further understand why the fetus wakes up at the time of delivery. Measurements will consist of electrocorticogram (ECoG), electrooculogram (EOG), tracheal pressure, diaphragmatic EMG, blood pressure and heart rate. Direct observation of the fetus will be made using a fiberoptic device (Olympus, Model BF 3C4). In project #2, acute and chronic experiments will be done in kittens and newborn lambs to know at what level of respiratory control loop hypoxia produces inhibition of breathing. Is it at the peripheral or central chemoreceptor level, at the respiratory muscles or is it a problem of mechanical coupling of the chest wall and abdomen? Measurements will include recording from carotid and phrenic nerve, diaphragmatic and intercostal EMG, esophageal pressure, ventilation, alveolar and arterial gases. In the classic lamb preparation, measurements of behavioral state will include ECoG, EOG, and EMG of the neck muscles. If we discover why hypoxia depresses ventilation early in life, we may understand why breathin is periodic in utero and why apnea is so frequent during the neonatal period.