Garland R J, Kinkead R, Milsom W K
Department of Zoology, University of British Columbia, Vancouver, Canada.
Respir Physiol. 1994 May;96(2-3):199-211. doi: 10.1016/0034-5687(94)90127-9.
A strong correlation between the arterial oxygen partial pressure (PaO2) values for the threshold of the hypoxic ventilatory response (HVR) and the shoulder of the oxyhemoglobin equilibrium curve (OEC) is retained in heterothermic rodents as body temperature changes despite changes in hemoglobin-oxygen affinity. It has been suggested that this may reflect either temperature-induced changes in the response characteristics of arterial chemoreceptors or an ability to sense changes in arterial O2 content (CaO2). This study examined the extent to which changing CaO2 independent of PaO2 with carbon monoxide could contribute to the HVR in heterothermic (golden-mantled ground squirrels) and non-heterothermic rodents (rats). The HVR of isocapnic, anaesthetized rodents was assessed during both hypoxic hypoxia, which alters PaO2 and CaO2 simultaneously, and carbon monoxide hypoxia, which alters CaO2 independent of PaO2. While both species exhibited ventilatory responses to hypoxic hypoxia and carbon monoxide hypoxia, the HVR of the squirrel was consistently stronger than that of the rat. Reductions in CaO2 independent of PaO2 could still produce 60% of the full HVR seen with hypoxic hypoxia in both species. Simultaneous changes in PaO2, however, were necessary to produce the full response. While it seems likely that the results can be explained by the changes in tissue PO2 which would occur at receptor sites under the various conditions, such an explanation is not totally supported by other studies.
在变温啮齿动物中，尽管血红蛋白与氧气的亲和力发生变化，但随着体温改变，低氧通气反应（HVR）阈值的动脉血氧分压（PaO2）值与氧合血红蛋白平衡曲线（OEC）的拐点之间仍保持着强烈的相关性。有人认为，这可能反映了动脉化学感受器反应特性的温度诱导变化，或者是感知动脉血氧含量（CaO2）变化的能力。本研究考察了用一氧化碳独立于PaO2改变CaO2时，对变温（金黄地鼠）和非变温啮齿动物（大鼠）的HVR有多大影响。在低氧性低氧（同时改变PaO2和CaO2）和一氧化碳性低氧（独立于PaO2改变CaO2）过程中，评估了等碳酸、麻醉状态下啮齿动物的HVR。虽然两个物种对低氧性低氧和一氧化碳性低氧均表现出通气反应，但松鼠的HVR始终比大鼠的更强。独立于PaO2降低CaO2仍可产生两个物种在低氧性低氧时所见完整HVR的60%。然而，PaO2的同时变化对于产生完整反应是必要的。虽然结果似乎可以用在各种条件下受体部位组织PO2的变化来解释，但其他研究并不完全支持这种解释。
