CONTROL OF FETAL AND NEONATAL BREATHING

我们想要1)定义子宫内的清醒状态，以评估其影响 胎儿的行为状态对呼吸的影响；以及2)找出为什么 新生儿对缺氧的反应包括一过性过度换气 通风不足。在项目1中，我们将使用眼球运动、睁开眼睛、头部 单突触和多突触反射的运动和大小以确定胎儿 保持清醒。一旦做到这一点，二氧化碳、皮肤刺激、 冷刺激、用药和其他程序(中脑 横切术)对胎儿呼吸的影响将与 行为状态的改变。我们想知道这些不同的刺激是否 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增加了体内的通风 在他醒着之前或只在他醒着的时候对二氧化碳的反应。对这一概念的理解 在子宫中引起觉醒的因素可能有助于我们进一步了解 为什么胎儿在分娩时醒来。测量结果将包括 皮层脑电(ECoG)、眼电(EOG)、气管压力、 横隔肌肌电、血压和心率。直接观察 胎儿将使用光纤设备(奥林巴斯，BF3C4型)制造。 在项目2中，急性和慢性实验将在小猫和 新生羔羊要知道呼吸控制环处于什么水平的缺氧 会抑制呼吸。是在外围还是在中央 呼吸肌的化学感受器水平，或者这是一个问题 胸壁和腹部的机械连接？测量结果将 包括从颈动脉和膈神经、横隔膜和 肋间肌电、食道压力、通气量、肺泡和动脉 毒气。在经典的羊肉准备中，行为状态的测量 将包括颈部肌肉的ECoG、EOG和EMG。如果我们找出原因 低氧会在生命早期抑制呼吸，我们可能会理解为什么呼吸 在宫内是周期性的，为什么在新生儿期间呼吸暂停如此频繁 句号。

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.