Leiter J C, Tenney S M
Respir Physiol. 1986 Sep;65(3):365-78. doi: 10.1016/0034-5687(86)90020-4.
We have examined the effect of steady-state hyperoxia on the ventilation of sea level (SL) cats and cats acclimatized to simulated high altitude (HA) at 5500 m for three weeks. Three groups of cats were studied. In group I, the ventilatory responses to 10%, 21% and 100% O2 were studied at SL, and after acclimatization to HA, the ventilatory responses to 10% and 100% O2 were measured. In group II the ventilatory responses and femoral artery and superior sagittal sinus blood gases were measured in two sets of cats, one at SL and one at HA, during exposure to the gases outlined in group I. In group III, we examined the effect of chronic vagotomy on the ventilatory responses to the gas mixtures outlined in group I. Breathing 100% O2 at SL had no significant effect on ventilation, tidal volume, respiratory frequency, or cerebral blood flow (inferred from the cerebral veno-arterial CO2 difference). Ventilation was constant in the HA acclimatized cats while breathing 10% and 100% O2, but the ventilatory pattern changed dramatically during hyperoxia: respiratory frequency increased and tidal volume fell. Breathing 100% O2 was associated with changes in CBF, and venous PCO2 that might be expected to stimulate ventilation, but the change in ventilatory pattern suggests to us that hyperoxic disinhibition of central respiratory processes (which were modified by HA acclimatization) is the mechanism whereby ventilation is sustained during hyperoxia at HA. After vagotomy at HA, ventilation remained constant while breathing 100% O2, but the changes in respiratory pattern were no longer apparent. Therefore, vagal afferents seems to have a role in determining the pattern, but not necessarily the absolute level, of ventilation during hyperoxia. Cats vagotomized at SL prior to HA exposure did not show any evidence of HA ventilatory acclimatization; thus, the vagi may also play a heretofore unrecognized role in the process of acclimatization.
我们研究了稳态高氧对海平面（SL）猫以及在5500米模拟高海拔（HA）环境中适应三周的猫的通气的影响。研究了三组猫。在第一组中，在海平面研究了对10%、21%和100%氧气的通气反应，在适应高海拔后，测量了对10%和100%氧气的通气反应。在第二组中，在两组猫中测量通气反应以及股动脉和上矢状窦血气，一组在海平面，一组在高海拔，期间暴露于第一组所述的气体中。在第三组中，我们研究了慢性迷走神经切断术对第一组所述气体混合物通气反应的影响。在海平面呼吸100%氧气对通气、潮气量、呼吸频率或脑血流量（根据脑静脉-动脉二氧化碳差值推断）没有显著影响。适应高海拔的猫在呼吸10%和100%氧气时通气保持恒定，但在高氧期间通气模式发生了显著变化：呼吸频率增加而潮气量下降。呼吸100%氧气与脑血流量和静脉血二氧化碳分压的变化有关，这些变化可能预期会刺激通气，但通气模式的变化向我们表明，高氧对中枢呼吸过程的去抑制作用（该过程因高海拔适应而改变）是高海拔高氧期间维持通气的机制。在高海拔进行迷走神经切断术后，呼吸100%氧气时通气保持恒定，但呼吸模式的变化不再明显。因此，迷走传入神经似乎在高氧期间决定通气模式方面发挥作用，但不一定决定通气的绝对水平。在暴露于高海拔之前在海平面进行迷走神经切断术的猫没有显示出任何高海拔通气适应的证据；因此，迷走神经在适应过程中可能也发挥了迄今未被认识到的作用。
