Katayama Keisho, Sato Kohei, Matsuo Hiroshi, Hotta Norio, Sun Zhihu, Ishida Koji, Iwasaki Ken-ichi, Miyamura Miharu
Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya 464-8601, Japan.
Respir Physiol Neurobiol. 2005 Mar;146(1):55-65. doi: 10.1016/j.resp.2004.11.007.
The purpose of this study was to clarify the changes in hypercapnic and hypoxic ventilatory responses (HCVR and HVR) after intermittent hypoxia and following the cessation of hypoxic exposure. Twenty-nine males were assigned to one of four groups, i.e., a hypoxic (EX1-H, n=7) or a control (EX1-C, n=7) group in Experiment 1, and a hypoxic (EX2-H, n=8) or a control (EX2-C, n=7) group in Experiment 2. In each experiment, the hypoxic tent system was utilized for intermittent hypoxia, and the oxygen levels in the tent were maintained at 12.3+/-0.2%. In Experiment 1, the EX1-H group spent 3 h/day in the hypoxic tent for 1 week. HCVR and HVR were determined before and after 1 week of intermittent hypoxia, and again 1 and 2 week after the cessation of hypoxic exposure. In Experiment 2, the subjects in the EX2-H group performed 3 h/day for 2 weeks in intermittent hypoxia. HCVR and HVR tests were carried out before and after intermittent hypoxia, and were repeated again after 2 weeks of the cessation of hypoxic exposure. The slope of the HCVR in the EX1-H group did not show a significant increase after 1 week of intermittent hypoxia, while HCVR in the EX2-H group increased significantly after 2 weeks of intermittent hypoxia. The HCVR intercept was unchanged following 1 or 2 weeks of intermittent hypoxia. There was a significant increase in the slope of the HVR after 1 and 2 weeks of intermittent hypoxia. The increased HCVR and HVR returned to pre-hypoxic levels after 2 weeks of the cessation of hypoxia. These results suggest that 3 h/day for 2 weeks of intermittent hypoxia leads to an increase in central hypercapnic ventilatory chemosensitivity, which is not accompanied by a re-setting of the central chemoreceptors, and that the increased hypercapnic and hypoxic chemosensitivities are restored within 2 weeks after the cessation of hypoxia.
本研究的目的是阐明间歇性低氧及低氧暴露停止后高碳酸血症和低氧通气反应（HCVR和HVR）的变化。29名男性被分为四组之一，即实验1中的低氧组（EX1-H，n = 7）或对照组（EX1-C，n = 7），以及实验2中的低氧组（EX2-H，n = 8）或对照组（EX2-C，n = 7）。在每个实验中，使用低氧帐篷系统进行间歇性低氧，帐篷内的氧气水平维持在12.3±0.2%。在实验1中，EX1-H组每天在低氧帐篷中停留3小时，持续1周。在间歇性低氧1周前后以及低氧暴露停止后1周和2周时测定HCVR和HVR。在实验2中，EX2-H组的受试者进行每天3小时、持续2周的间歇性低氧。在间歇性低氧前后进行HCVR和HVR测试，并在低氧暴露停止2周后再次重复测试。EX1-H组的HCVR斜率在间歇性低氧1周后未显示出显著增加，而EX2-H组的HCVR在间歇性低氧2周后显著增加。间歇性低氧1周或2周后，HCVR截距未发生变化。间歇性低氧1周和2周后，HVR斜率显著增加。低氧暴露停止2周后，增加的HCVR和HVR恢复到低氧前水平。这些结果表明，每天3小时、持续2周的间歇性低氧会导致中枢性高碳酸血症通气化学敏感性增加，且不伴有中枢化学感受器的重置，并且高碳酸血症和低氧化学敏感性增加在低氧暴露停止后2周内恢复。
