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首页> 外文期刊>American Journal of Physiology >Time-dependent modulation of carotid body afferent activity during and after intermittent hypoxia.
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Time-dependent modulation of carotid body afferent activity during and after intermittent hypoxia.

机译：间歇性缺氧期间和之后，颈动脉身体传入活动的时间依赖性调制。

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摘要

The ventilatory response to several minutes of hypoxia consists of various time-dependent phenomena, some of which occur during hypoxia (e.g., short-term depression), whereas others appear on return to normoxia (e.g., posthypoxic frequency decline). Additional phenomena can be elicited by acute, intermittent hypoxia (e.g., progressive augmentation, long-term facilitation). Current data suggest that these phenomena originate centrally. We tested the hypothesis that carotid body afferent activity undergoes time-dependent modulation, consistent with a direct role in these ventilatory phenomena. Using an in vitro rat carotid body preparation, we found that 1) afferent activity declined during the first 5 min of severe (40 Torr Po(2)), moderate (60 Torr Po(2)), or mild (80 Torr Po(2)) hypoxia; 2) after return to normoxia (100 Torr Po(2)) and after several minutes of moderate or severe hypoxia, afferent activity was transiently reduced compared with prehypoxic levels; and 3) with successive 5-min bouts of mild, moderate, or severe hypoxia, afferent activity during bouts increased progressively. We call these phenomena sensory hypoxic decline, sensory posthypoxic decline, and sensory progressive augmentation, respectively. These phenomena were stimulus specific: similar phenomena were not seen with 5-min bouts of normoxic hypercapnia (100 Torr Po(2) and 50-60 Torr Pco(2)) or hypoxic hypocapnia (60 Torr Po(2) and 30 Torr Pco(2)). However, bouts of either normoxic hypercapnia or hypocapnic hypoxia resulted in sensory long-term facilitation. We suggest time-dependent carotid body activity acts in parallel with central mechanisms to shape the dynamics of ventilatory responses to respiratory chemostimuli.
机译：几分钟缺氧的通气反应由多种时间相关的现象组成，其中一些发生在缺氧期间（例如，短期抑郁），而另一些则恢复正常时出现（例如，低氧后频率下降）。急性，间歇性缺氧可引起其他现象（例如，进行性增强，长期促进）。当前数据表明，这些现象是集中发生的。我们检验了以下假设：颈动脉的身体传入活动经历时间依赖性调制，这与这些通气现象的直接作用一致。使用体外大鼠颈动脉体制剂，我们发现1）在严重（40 Torr Po（2）），中度（60 Torr Po（2））或轻度（80 Torr Po（ 2））缺氧; 2）恢复正常氧量（100 Torr Po（2））后，经过几分钟的中度或严重缺氧，与缺氧前水平相比，传入活动暂时减少; 3）连续5分钟的轻度，中度或重度低氧发作，发作期间的传入活动逐渐增加。我们将这些现象分别称为感觉缺氧性下降，感觉缺氧性下降和感觉进行性增强。这些现象是特定于刺激的：在常氧性高碳酸血症（100 Torr Po（2）和50-60 Torr Pco（2））或低氧性低碳酸血症（60 Torr Po（2）和30 Torr Pco （2））。然而，常氧性高碳酸血症或低碳酸血症性缺氧的发作导致感觉长期促进。我们建议时间依赖性颈动脉活动与中央机制平行，以塑造对呼吸化学趋化的通气反应的动力学。

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