Peever J H, Stephenson R
University of Toronto, Department of Physiology, Ont., Canada.
Respir Physiol. 1997 Sep;109(3):241-8. doi: 10.1016/s0034-5687(97)00056-x.
We investigated whether resting ventilation and the hypercapnic ventilatory response vary with time of day in awake adult rats. Respiratory frequency (fR), tidal volume (VT), inspired ventilation (VI), inspiratory interval (tI), carbon dioxide production (VCO2) and abdominal temperature (Tb) were measured before and during a hypercapnic stimulus (3.5% CO2 in air) at 10:00 and 22:00 h. VCO2, Tb and mean inspiratory air flow (VT/tI) were significantly higher at 22:00 h in air. VI/VCO2 was similar at 10:00 and 22:00 h. VI was significantly elevated by hypercapnia and the response at 22:00 h was 2.3 times greater than that at 10:00 h. VT/tI was unchanged at 10:00 h but significantly increased by hypercapnia at 22:00 h. VCO2 was significantly depressed at 10:00 h but not at 22:00 h. Tb was unaffected by hypercapnia. We conclude that the metabolic and ventilatory responses to hypercapnia are dependent on the time of day.
我们研究了清醒成年大鼠静息通气和高碳酸通气反应是否随一天中的时间而变化。在上午10:00和晚上22:00对高碳酸刺激（空气中3.5%二氧化碳）之前及期间测量呼吸频率（fR）、潮气量（VT）、吸入通气量（VI）、吸气间隔（tI）、二氧化碳产生量（VCO2）和腹部温度（Tb）。空气中，22:00时VCO2、Tb和平均吸气气流（VT/tI）显著更高。上午10:00和晚上22:00时VI/VCO2相似。高碳酸血症使VI显著升高，22:00时的反应比10:00时大2.3倍。上午10:00时VT/tI不变，但在22:00时高碳酸血症使其显著增加。上午10:00时VCO2显著降低，但晚上22:00时未降低。Tb不受高碳酸血症影响。我们得出结论，对高碳酸血症的代谢和通气反应取决于一天中的时间。
