Bascom D A, Clement I D, Cunningham D A, Painter R, Robbins P A
University Laboratory of Physiology, Oxford, U.K.
Respir Physiol. 1990 Nov;82(2):161-76. doi: 10.1016/0034-5687(90)90032-t.
One hypothesis concerning the origin of hypoxic ventilatory decline is that hypoxia acts centrally to depress peripheral chemoreflex loop activity. To investigate possible changes in peripheral chemoreflex loop activity during sustained, isocapnic hypoxia, the ventilatory responses to four one minute pulses of either extra hypoxia (45 Torr) or carbon dioxide (8 Torr above resting levels) were measured in man at minutes 2, 7, 12, and 17 of a 23 min isocapnic, hypoxic period (50 Torr). For hypoxia, the first pulse response (130%) was significantly greater (P less than 0.05) than the fourth response (74%). For CO2, pulse responses 2 and 3 (101 and 103%, respectively) were significantly greater (P less than 0.05) than the fourth response (91%). A central depression of peripheral chemoreflex loop activity should affect peripheral sensitivities to CO2 and hypoxia equally. Our results suggest that the peripheral sensitivity to hypoxia declined more than that to CO2, implying a peripheral chemoreceptor origin for hypoxic ventilatory decline.
关于低氧通气反应降低起源的一种假说是，低氧在中枢发挥作用，抑制外周化学反射环活动。为了研究持续性等碳酸血症性低氧期间外周化学反射环活动的可能变化，在23分钟等碳酸血症性低氧期（50托）的第2、7、12和17分钟，测量了人体对额外低氧（45托）或二氧化碳（比静息水平高8托）的四个1分钟脉冲的通气反应。对于低氧，第一个脉冲反应（130%）显著大于（P<0.05）第四个反应（74%）。对于二氧化碳，第2和第3个脉冲反应（分别为101%和103%）显著大于（P<0.05）第四个反应（91%）。外周化学反射环活动的中枢抑制应同样影响外周对二氧化碳和低氧的敏感性。我们的结果表明，外周对低氧的敏感性下降幅度大于对二氧化碳的敏感性，这意味着低氧通气反应降低起源于外周化学感受器。
