Ventilatory responses to chemoreceptor stimulation after hypoxic acclimatization in awake goats.
Ventilatory responses to chemoreceptor stimulation after hypoxic acclimatization in awake goats.
复制标题
清醒山羊缺氧适应后对化学感受器刺激的通气反应。
DOI：
10.1152/jappl.1990.69.4.1236
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Bisgard,GE
中科院分区：
文献类型：
--
作者：
Engwall,MJ;Bisgard,GE
我们的目的是检验这一假设，即暴露于长期缺氧的结果改变反应的化学感受器刺激。相对于其他物种，醒着的山羊对缺氧的适应发生得很快。我们测试的敏感性的中央和外周化学感受器化学刺激之前和之后4小时的等二氧化碳或poikilocapnic缺氧（动脉PO2 40托）。我们证实，动脉PCO2进行性下降，达到一个稳定的值后4小时的缺氧暴露（poikilocapnic组）。在等二氧化碳组中，吸入每分钟通气量在相同的时间过程中增加。因此，两组均发生了适应。在山羊中，等二氧化碳缺氧并没有导致过度通气恢复到常氧，而poikilocapnic缺氧引起过度通气，表明不同的机制驯化和持续过度通气恢复到常氧。山羊暴露于等二氧化碳缺氧表现出增加的斜率的CO2反应曲线。山羊暴露于poikilocapnic缺氧没有增加斜率，但表现出平行的CO2反应曲线的平移。在长时间缺氧后，两组均未表现出对团注NaCN注射或多巴胺输注的反应的显著变化。然而，两组在随后急性暴露于等二氧化碳缺氧的缓解反应中表现出相似的显著增加。缺氧诱导敏感性的增加，这是不依赖于缺氧暴露的方式（isocapnic与poikilocapnic），加强了颈动脉化学感受器在诱导适应缺氧的关键作用。
Our objective was to test the hypothesis that exposure to prolonged hypoxia results in altered responsiveness to chemoreceptor stimulation. Acclimatization to hypoxia occurs rapidly in the awake goat relative to other species. We tested the sensitivity of the central and peripheral chemoreceptors to chemical stimuli before and after 4 h of either isocapnic or poikilocapnic hypoxia (arterial PO2 40 Torr). We confirmed that arterial PCO2 decreased progressively, reaching a stable value after 4 h of hypoxic exposure (poikilocapnic group). In the isocapnic group, inspired minute ventilation increased over the same time course. Thus, acclimatization occurred in both groups. In goats, isocapnic hypoxia did not result in hyperventilation on return to normoxia, whereas poikilocapnic hypoxia did cause hyperventilation, indicating a different mechanism for acclimatization and the persistent hyperventilation on return to normoxia. Goats exposed to isocapnic hypoxia exhibited an increased slope of the CO2 response curve. Goats exposed to poikilocapnic hypoxia had no increase in slope but did exhibit a parallel leftward shift of the CO2 response curve. Neither group exhibited a significant change in response to bolus NaCN injections or dopamine infusions after prolonged hypoxia. However, both groups demonstrated a similar significant increase in the ventilatory response to subsequent acute exposure to isocapnic hypoxia. The increase in hypoxic ventilatory sensitivity, which was not dependent on the modality of hypoxic exposure (isocapnic vs. poikilocapnic), reinforces the key role of the carotid chemoreceptors in ventilatory acclimatization to hypoxia.