Frappell P B, Baudinette R V, MacFarlane P M, Wiggins P R, Shimmin G
Department of Zoology, La Trobe University, Melbourne, Victoria 3086, Australia.
Physiol Biochem Zool. 2002 Jan-Feb;75(1):77-82. doi: 10.1086/324769.
Metabolic and ventilatory variables were measured in a large semifossorial marsupial, the hairy-nosed wombat (Lasiorhinus latifrons, 21.9 kg). In normoxia, the rate of oxygen consumption was 63% of that predicted for a similar-sized marsupial, and the level of ventilation (V(E)) was such that the convective requirement (V(E)/VO2) was similar to other mammals. Exposure to hypercapnia (5% CO(2)) evoked a hyperventilatory response (3.55 x normoxia) that was no different to that observed for epigeal (surface-dwelling) marsupials; the increase in V(E) was primarily achieved with an increase in tidal volume. Exposure to hypoxia (15% to 8% O(2)) resulted in a hyperventilation (principally through an increase in frequency), although the response was blunted (in 8% O(2), 1.85 x normoxia) and only at the severest levels did hypometabolism contribute. The attenuated response to hypoxia in the wombat is presumably a reflection of a semifossorial lifestyle and a tolerance to this respiratory stimulant.
在一种大型半穴居有袋动物——毛鼻袋熊（Lasiorhinus latifrons，体重21.9千克）身上测量了代谢和通气变量。在常氧条件下，耗氧率为体型相似的有袋动物预测值的63%，通气水平（V(E)）使得对流需求（V(E)/VO2）与其他哺乳动物相似。暴露于高碳酸血症（5% CO(2)）会引发过度通气反应（常氧条件下的3.55倍），这与地面栖息的有袋动物所观察到的反应并无差异；V(E)的增加主要是通过潮气量的增加来实现的。暴露于低氧环境（15%至8% O(2)）会导致过度通气（主要是通过频率增加），尽管反应有所减弱（在8% O(2)时为常氧条件下的1.85倍），并且只有在最严重的水平下低代谢才起作用。袋熊对低氧的反应减弱大概反映了其半穴居的生活方式以及对这种呼吸刺激物的耐受性。
