DISCHARGE PATTERNS OF CAROTID BODY CHEMORECEPTORS

颈动脉体化学感受器的放电模式将是 研究了 选择禽类动物模型，因为禽类颈动脉 身体化学感受器在结构上几乎相同， 对哺乳动物的颈动脉体起作用， 提供了强大的实验优势， 用于控制动脉血气的UDV通气。 实验提出了联合收割机（UDV）、在线血气分析 测量，单单位神经记录技术，和 计算机化在线数据采集，以测试生理 颈动脉体化学感受器的反应， 这在哺乳动物模型中是不可能的 颈动脉体化学感受器是多模式的， 动脉PO2、PCO2和其他刺激。 该项目将 确定单一受体对动脉pH的反应， 血压. 该项目还将分析时间 单个化学感受器动作电位的发生 暴露于不同的静态刺激水平会导致不同的 感受器放电模式 模式差异可能是 携带差异刺激的神经编码机制 将信息发送到中央呼吸控制器，并且可以 代表了转导机制的根本差异， 氧气和二氧化碳。 与潮气量相关的动脉PCO_2动态振荡 假设呼吸引起前馈控制信号 通过颈动脉体在运动中进行辅助控制。 本项目将使用UDV诱导的动脉斜坡振荡 PCO2、PO2检测颈动脉体的频率敏感性 化学感受器（它会放大前馈信号， 锻炼）。 UDV诱导的动脉PO2正弦振荡， PCO2将用于测试受体的频率响应 （确定受体对呼吸系统变化的反应） 速率），它将测试振荡之间的相位差 PO2或PCO2受体反应（影响 到达中央控制器的化学感受器放电）。 正常的动态和静态颈动脉体的许多方面 化学感受器敏感性仍不确定。 重要的是要 研究这些正常的生理反应， 颈动脉体化学感受器在控制 健康和疾病中的肺通气。

The discharge patterns of carotid body chemoreceptors will be studied. An avian animal model was chosen because avian carotid body chemoreceptors are nearly identical in structure and function to mammalian carotid bodies, and because the avian lung offers the powerful experimental advantage of unidirectional ventilation (UDV) for controlling arterial blood gases. Experiments are proposed that combine (UDV), on-line blood gas measurement, single unit neural recording techniques, and computerized on-line data acquisition to test the physiological responses of carotid body chemoreceptors in ways difficult or impossible with a mammalian model. Carotid body chemoreceptors are multimodal, responding to arterial PO2, PCO2, and other stimuli. This project will determine the response of single receptors to arterial pH and blood pressure. This project will also analyze the temporal occurrence of action potentials from single chemoreceptors exposed to different static levels of stimuli cause different receptor discharge patterns. Pattern differences could be a neural encoding mechanism for carrying differential stimulus information to the central respiratory controller, and may represent fundamental differences in transduction mechanisms for O2 and CO2. Dynamic oscillations of arterial PCO2 associated with tidal breathing are hypothesized to cause a feed-forward control signal via the carotid bodies for ventilatory control during exercise. This project will use UDV-induced ramp oscillations of arterial PCO2, and PO2 to test the rate sensitivity of carotid body chemoreceptors (which would amplify the feed-forward signal in exercise). UDV-induced sinusoidal oscillations of arterial PO2 and PCO2 will be used to test the frequency response of the receptors (determining the receptor response to changes in respiratory rate), and it will test for phase differences between oscillating PO2 or PCO2 receptor response (which affects the efficacy of chemoreceptor discharge arriving at the central controller). Many aspects of the normal dynamic and static carotid body chemoreceptor sensitivity remain uncertain. It is important to study these normal physiological responses so that we can define the roles of carotid body chemoreceptors in the control of pulmonary ventilation in health and disease.