DISCHARGE PATTERNS OF CAROTID BODY CHEMORECEPTORS

将研究颈动脉体化学感受器的放电模式。 一个 选择鸟类动物模型是因为它们的颈动脉体接近 在结构和功能上与哺乳动物相同， 禽肺提供了强大的实验优势， 用于控制动脉血气的UDV通气。 实验 提出联合收割机UDV、在线血气测量、单台 神经记录技术，反射反射反应的测量， 和计算机化的在线数据采集，以测试生理 颈动脉体的反应，以困难或不可能的方式与一个 哺乳动物模型 颈动脉体化学感受器是多模式的，对动脉PO2有反应， PCO2和其他刺激。 该项目将决定 动脉PO2、PCO2、pH和血压的单一受体。 这 项目还将分析动作电位的时间发生， 化学感受器暴露于不同的动脉血氧分压和二氧化碳分压水平 （用UDV控制）来检验两种刺激引起的假设 不同的受体放电模式。 模式差异可能是 用于携带差分刺激信息的神经编码机制 可能是由于不同的转导机制， 氧气和二氧化碳。 与潮气呼吸相关的动脉PCO2的动态振荡是 被认为提供相位的、中枢门控的兴奋刺激，并且 可能是与代谢率相关的前馈控制信号。 这 项目将使用精确的UDV诱导动脉PCO2振荡来测试 速率敏感性的颈动脉男孩化学感受器（这将放大他们的 振荡信号）和它们的频率响应。 反射的重要性 由颈动脉体化学感受器介导的动脉PCO2振荡将 也可以量化。 正常动态和静态颈动脉体化学感受器的许多方面 敏感性仍然不确定。 研究这些正常的 生理反应，以确定颈动脉体的作用， 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 their carotid bodies are nearly identical in structure and function to those of mammals, 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, measurements of reflex ventilatory responses, and computerized on-line data acquisition to test the physiological responses of carotid bodies 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 PO2, PCO2, pH, and blood pressure. This project will also analyze the temporal occurrence of action potential from chemoreceptors exposed to different static level of arterial PO2 and PCO2 (controlled with UDV) to test the hypothesis that the two stimuli cause different receptor discharge patterns. Pattern differences could be a neural encoding mechanism for carrying differential stimulus information centrally, and might be due to difference in transduction mechanisms for oxygen and carbon dioxide. Dynamic oscillations of arterial PCO2 associated with tidal breathing are thought to provide a phasic, centrally gated ventilatory stimulus, and perhaps a feed-forward control signal related to metabolic rate. This project will use precise UDV induced arterial PCO2 oscillations to test the rate sensitivity of carotid boy chemoreceptors (which would amplify their oscillatory signal) and their frequency response. The reflex importance of arterial PCO2 oscillations mediated by carotid body chemoreceptors will also be quantitated. Many aspects of the normal dynamic and static carotid body chemoreceptor sensitivity remain uncertain. It is important to study these normal physiological responses to define the role of the carotid body in the control of pulmonary ventilation in health and disease.