STATIC AND DYNAMIC CAROTID CHEMORECEPTOR RESPONSES

静态和动态颈动脉化学感受器反应

• 批准号: 3448742
• 负责人: STEVEN C HEMPLEMAN
• 金额: $ 5.07万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1985
• 资助国家: 美国
• 起止时间: 1985-01-01 至 1987-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3448742
• 关键词: acidity /alkalinity; action potentials; carbon dioxide tension; chemoreceptors; electrophysiology; exercise; hypoxia; neural transmission; respiratory gas level; single cell analysis; stimulus /response

Although avian and mammalian carotid body chemoreceptors are known to be structurally similar, and to serve similar functions in the control of ventilation, the stimulus-response characteristics of single unit avian carotid chemoreceptors are poorly documented. The proposed study will establish functional similarities and differences using single unit neural recording techniques. Static and dynamic responses of avian carotid chemoreceptors to their adequate stimuli will be defined, and their responses to substances known to affect mammalian carotid bodies--eg. oligomycin, KCN, and norepinephrine--characterized. The pattern of avian carotid body discharge will be quantitated with interspike interval histograms. The independent and interactive effects of steady levels of pH, PCO2, and PO2 on avian carotid chemoreceptors will be determined from single unit stimulus-response curves. Receptor responses to hypocapnic-hypoxic stimuli will be of special interest because the superior hypoxic tolerance of birds compared to mammals may be partly due to a stronger hypoxic drive in birds. Arterial PCO2 oscillations linked to tidal breathing affect carotid chemoreceptor discharge patterns in mammals. Since arterial PCO2 oscillations are predicted to be even larger in birds, correlations will be made between avian carotid chemoreceptor discharge pattern, and the arterial PCO2 oscillations measured wiith an intravascular pH electrode. The hypothesis that dynamic responses of carotid chemoreceptors may help couple ventilation to metabolism by detecting exercise-induced changes in arterial PCO2 oscillations will be tested. Dynamic receptor responses will be quantitated while forcing arterial PCO2 oscillations of varying shape and frequency, using artificial, unidirectional pulmonary ventilation. Unidirectional ventilation of the avian lung offers a powerful tool for controlling arterial gas tensions, allowing a systems analysis approach to the study of receptor frequency response. Sinusoidal PCO2 oscillations will be used to determine the frequency response of avian carotid chemoreceptors, and ramp oscillations with varying up and down slopes, but constant period and amplitude, will be used to determine the effect of rate of PCO2 change on receptor discharge. Similar experiments would be much more difficult in mammals. The results of this study will broaden our knowledge of avian carotid body chemoreceptor responses, and serve to guide further studies of carotid bodies in general.

尽管已知禽和哺乳动物颈动脉体化学感受器 结构相似，并在控制中发挥相似的功能 通风，单个单位禽的刺激反应特性 颈动脉化学感受器的文献很少。 拟议的研究将 使用单个单元神经建立功能相似性和差异 记录技术。 禽颈静脉的静态和动态响应 将定义化学感受器的足够刺激，并将其定义 对已知会影响哺乳动物颈动脉体的物质的反应 - eg。 寡霉素，KCN和去甲肾上腺素 - 特征。 鸟类的模式 颈动脉身体排放将用串联间隔进行定量 直方图。 稳定水平的pH，PCO2和 将从单个单元确定禽颈化学感受器上的PO2 刺激反应曲线。 受体对低胃催眠刺激的反应 将特别感兴趣，因为鸟类的优势低氧耐受性 与哺乳动物相比，可能部分是由于较强的低氧驱动 鸟类。 与潮汐呼吸有关的动脉PCO2振荡影响颈动脉 哺乳动物的化学感受器放电模式。 自动脉PCO2以来 预计鸟类的振荡在鸟类中会更大，相关性将是 在禽颈化学感受器放电模式和 动脉PCO2振荡测量了血管内pH电极。 颈动脉化学感受器的动态反应可能有助于 通过检测运动诱导的变化，将通风与新陈代谢相对 将测试动脉PCO2振荡。 动态受体反应将 在强迫不同形状的动脉PCO2振荡时进行定量 和频率，使用人工，单向肺通风。 禽肺的单向通风为 控制动脉气体张力，允许系统分析方法 受体频率反应的研究。 正弦PCO2振荡 将用于确定禽颈的频率响应 化学感受器和坡道振荡，上下斜坡变化，但 恒定周期和振幅将用于确定速率的影响 PCO2在受体放电上的变化。 类似的实验会很大 哺乳动物更困难。 这项研究的结果将扩大我们的 了解禽颈体化学感受器的反应，并有助于指导 总体上对颈动脉体的进一步研究。