Olson E B, Bohne C J, Dwinell M R, Podolsky A, Vidruk E H, Fuller D D, Powell F L, Mitchel G S
The John Rankin Laboratory of Pulmonary Medicine, Department of Preventive Medicine, University of Wisconsin School of Medicine, Madison, 53705-2368, USA.
J Appl Physiol (1985). 2001 Aug;91(2):709-16. doi: 10.1152/jappl.2001.91.2.709.
We tested the hypothesis that unanesthetized rats exhibit ventilatory long-term facilitation (LTF) after intermittent, but not continuous, hypoxia. Minute ventilation (VE) and carbon dioxide production (VCO(2)) were measured in unanesthetized, unrestrained male Sprague-Dawley rats via barometric plethysmography before, during, and after exposure to continuous or intermittent hypoxia. Hypoxia was either isocapnic [inspired O(2) fraction (FI(O(2))) = 0.08--0.09 and inspired CO(2) fraction (FI(CO(2))) = 0.04] or poikilocapnic (FI(O(2)) = 0.11 and FI(CO(2)) = 0.00). Sixty minutes after intermittent hypoxia, VE or VE/VCO(2) was significantly greater than baseline in both isocapnic and poikilocapnic conditions. In contrast, 60 min after continuous hypoxia, VE and VE/VCO(2) were not significantly different from baseline values. These data demonstrate ventilatory LTF after intermittent hypoxia in unanesthetized rats. Ventilatory LTF appeared similar in its magnitude (after accounting for CO(2) feedback), time course, and dependence on intermittent hypoxia to phrenic LTF previously observed in anesthetized, vagotomized, paralyzed rats.
未麻醉的大鼠在间歇性而非持续性低氧后会出现通气长期易化（LTF）。通过气压体积描记法，在未麻醉、不受束缚的雄性Sprague-Dawley大鼠暴露于持续性或间歇性低氧之前、期间和之后，测量其分钟通气量（VE）和二氧化碳产生量（VCO₂）。低氧情况分为等碳酸血症[吸入氧分数（FI(O₂)）= 0.08 - 0.09且吸入二氧化碳分数（FI(CO₂)）= 0.04]或变碳酸血症（FI(O₂)= 0.11且FI(CO₂)= 0.00）。间歇性低氧60分钟后，在等碳酸血症和变碳酸血症两种情况下，VE或VE/VCO₂均显著高于基线。相比之下，持续性低氧60分钟后，VE和VE/VCO₂与基线值无显著差异。这些数据表明未麻醉大鼠在间歇性低氧后出现通气LTF。通气LTF在幅度（在考虑二氧化碳反馈后）、时间进程以及对间歇性低氧的依赖性方面，似乎与先前在麻醉、迷走神经切断、麻痹的大鼠中观察到的膈神经LTF相似。
